["53.\tPollen grains, dust, mites, dander are allergens. \t62.\tRefer answer no. 61.\t \t\tBody produces IgE antibodies on exposure to \t63.\tA: Antigen binding site \t\tD: Light chain allergens and release of chemicals like histamine \t\tE: Heavy chain and serotonin from the mast cells. \t\tF: Disulfide bonds \t64.\tPrimary lymphoid organs: Here immature 54. Active immunity Passive immunity lymphocytes differentiate into antigen-sensitive \u2022 Person is exposed \u2022 Readymade antibodies lymphocytes. to antigens in the are given directly form of living or to protect against \t\tSecondary lymphoid organs: These organs are dead microbes or antigens the sites for interaction of lymphocytes with the some other proteins, antigen, which then proliferate to become effector his body produces cells. antibodies against antigens. \t65.\tThe two types of immunity are innate and passive immunity. \u2022 It is slow and takes \u2022 The response is fast. time to respond. \t\tInnate immunity is a non-specific type of defence that provides barriers to the entry of pathogens \u2022 Example: Vaccines \u2022 Example: Tetanus in our body. Example: skin, Polymorpho-nuclear leukocytes (PMNL), interferons, acid in stomach such as BCG and injection or antitoxin etc. DPT against snake venom \t\tWhen ready-made antibodies are directly given to protect the body against foreign agents, it \t55.\tSuch response is called allergy. Body produces is called passive immunity. In new born some IgE antibodies on exposure to allergens and antibodies are already present which are received release of chemicals like histamine and serotonin from mother through placenta. This is also a type from the mast cells. of passive immunity. \t 56.\t(a)\t Antibody is IgE, chemicals are histamines and \t66.\tFirst milk secreted by mother after the birth of serotonins child. It contains antibodies IgA which provides passive immunity to the new born. \t \t(b)\t Drug: Antihistamine, adrenalin and steroids. \t67.\tTetanus is caused due to deadly bacteria which \t57.\t(a)\t Allergy is the exaggerated response of the requires quick action, any delay otherwise will immune system to certain antigens present prove fatal. Therefore, tetanus antitoxins are in the environment. administered directly via vaccine which provides instant response against tetanus toxin. \t \t(b)\t Body produces IgE antibodies on exposure to allergens and release of chemicals like \t68.\t(a) Mucus coating of the epithelium lining the histamine and serotonin from the mast cells. respiratory, gastrointestinal and urinogenital tracts \t58.\tThe antibodies are produced in the body when vaccinated which would neutralize the pathogenic \t \t(b)\t Tears, acid in stomach agents during actual infection. The vaccines also generate memory \u2013 'B and T- cells' that recognize \t \t (c)\t Cytokine barriers the pathogen quickly on subsequent exposure and destroy them by producing large amount of \t \t(d)\t PMNL antibodies. \t69.\tActive immunity: In this host is exposed to \t59.\tTetanus antitoxin is given against deadly microbe antigens, which may be in the form of living or causing tetanus where body requires quick dead microbes or other proteins and antibodies response. are produced in the host body in response of this. \t60.\t(a)\t Thymus is a primary lymphoid organ and it \t70.\t(a)\t Refer answer no. 58. provides micro-environment for the develop- \t \t(b)\t Refer answer no. 59. ment and maturation of T-lymphocytes. \t71.\t(a)\t An antibody molecule \t \t(b)\t T-lymphocytes, they give cell mediated re- \t \t(b)\t A\u2013Antigen binding site sponse in the body against a pathogen. \t \t \t B\u2013Light chain \t 61.\t (i)\t Humoral immune response: In this type of acquired immunity, antibodies produced by \t \t (c)\t B-lymphocytes (B-cells). B-lymphocytes are found in blood thus called so. \t 72.\t(a)\t Bone marrow\t \t \t(b)\t T\t he lymphocytes produced in bone marrow \t \t(ii)\t Cell mediated immune response: T-lympho- cytes are responsible for this type of acquired migrate to secondary lymphoid organs like immunity. spleen, lymph nodes, etc. There they interact with antigen and become effector cells. \t \t \t The T-cells help B cells produce antibodies. 200 Biology\u201312","73.\tRefer answer no. 66. \t84.\tSource is Cannabis sativa. It affects cardiovascular \t74.\tThe lymphocytes produced in bone marrow system of the human body. migrate to secondary lymphoid organ like spleen \t85.\tSmack is obtained from Papaver somniferum. and there they interact with antigen and become It binds to specific opioid receptors present in effector cells. It acts as a filter of the blood by our central nervous system and gastrointestinal trapping blood-borne microorganisms. Spleen tract. also has a large reservoir of erythrocytes. \t86.\tA.\t Opium \t75.\tVaccines are in the form of living or dead microbes \t\tB.\t Affects cardiovascular system of the body or their proteins which when introduced in body \t\tC.\t Cocaine activates active immune system of the body. Body \t\tD.\tIt is a potent stimulant of CNS and produces starts producing antibodies and protecting from further infections. sense of euphoria and increased energy, it also causes hallucinations. \t76.\tInnate immunity is present at the time of birth in humans. It is accomplished by providing different \t87.\tSymptoms of allergic reactions include sneezing, types of barriers. watery eyes, running nose and difficulty in breathing. \t \t (i)\t Physical barriers: These barriers do not allow pathogens and foreign agents to enter the \t\tImmune system overreacts by producing body, e.g., skin and mucous membranes of antibodies called Immunoglobulin E (IgE). These digestive, respiratory and urinogenital tract antibodies travel to cells that release chemicals, do not allow microbes to enter the body. causing an allergic reaction. \t \t(ii)\t Physiological barriers: acid in the stomach, \t 88.\t(a)\t (i) Cannabis sativa sweat, tears of eyes and saliva prevent \t \t (ii)\t Cannabinoids are obtained from the microbial growth. inflorescence of the plant. \t77.\tCytokine barriers: Virus injected cells secrete protein called interferons which protect non- \t \t(iii)\t These drugs affect cardiovascular infected cells from further injection. system of the body. They affect brain areas that influence pleasure, memory, \t 78.\t(a)\t Retrovirus. These are named so because they thinking, concentration, movement and have RNA as genetic material and have coordination. reverse transcriptase enzyme which makes DNA from RNA in cell. OR \t \t(b)\t Infected blood transfusion, sharing syringes \t \t(b)\t There is lymphoid tissue also located within or needles. the lining of the major tracts respiratory, digestive and urogenital tracts called mucosal- \t79.\tMacrophages and Helper T-cells act as HIV associated lymphoid tissue (MALT). It factory. The virus enters macrophages or helper constitutes about 50 per cent of the lymphoid T-cells where RNA of the virus replicates to tissue of our body. form viral DNA with the help of the enzyme reverse transcriptase. The viral DNA then gets \t 89.\t (i)\t Cannabinoids affect cardiovascular systems. incorporated into host cell\u2019s DNA and directs \t \t(ii)\t It affects the brain by interacting with infected cells to produce new virus particles. cannabinoid receptors. \t80.\tTumor cells are dangerous as these cells actively divide and grow, they also starve the normal cells \t \t(iii)\tIt causes addiction, may later affect overall by competing for vital nutrients. health & relations of a person in society. \t81.\tNormal cells do not show cancerous growth as \t90.\t(a)\t Provide preformed antibodies \/ anti-toxins for they have the property of contact inhibition quick response in case of infection by deadly microbes (tetanus) or snake bite \t 82.\t(a)\t The contact inhibition prevents normal cells to change into cancerous cells. \t \t(b)\t Reduces symptoms of allergy \t \t(b)\t Every cell has several genes called cellular \t \t \t (c)\t Provides passive immunity \/ antibodies \/ Ig A oncogenes (c-onc) or proto oncogenes in normal to new born cells which are not activated. Under certain conditions these genes gets activated and \t \t(d)\t Protection of non-infected cells from further transform normal cells into cancerous cells. viral infection \t83.\tWithdrawal syndrome is the state experienced by \t91.\tHIV enters macrophages, reverse transcription drug abusers when their regular dose of alcohol occurs and new viruses are formed. These cells or drug is suddenly discontinued. It is often are then called as HIV factory. These viruses then characterized by anxiety, shakiness, nausea and attack helper T-lymphocytes. sweating. \t 92.\t(a)\t Source of the drug is Papaver sominiferum or Poppy plant, the drug is obtained from its latex or acetylation of morphine. Human Health and Diseases \u2009201","(b)\t Heroin acts as a depressant and slows down It is transmitted by bite of female mosquito body functions. vectors. \t95.\tRefer answer no. 46. 3 Marks Questions \t 96.\t(a)\t Gametocyte is the infective stage of \t 93.\tSalmonella typhi causes typhoid. Diagnostic Plasmodium. symptoms are constipation, stomach pain, \t \t(b)\t Fever occurs due to release of haemozoin toxin headache, weakness, loss of appetite, high fever. when RBC ruptures \t\tThe disease is transmitted through contaminated \t \t (c)\t Gametocytes enter the female mosquito food and water. \u2193 \t94.\tTwo diseases caused by round worms are Formation of gametes in the mosquito\u2019s intestine Ascariasis and elephantiasis. \u2193 \t\tAscariasis is caused by Ascaris. Infection occurs Fertilisation through contaminated water, vegetables and fruits. \u2193 Sporozoites released from the intestine \t\tElephantiasis is caused by filarial worms Wuchereria bancrofti and W malayi. It is \u2193 transmitted via female mosquitoes. Sporozoites enter the mosquito's salivary glands \t\tElephantiasis is also called as filariasis and is \u2193 caused by Wuchereria bancrofti or filarial worm. Sporozoites get injected when the mosquito bites an human being \t97.\tDifferent stages in life cycle of malarial parasite in human body can be explained by the following life cycle of malarial parasite. When the mosquito bites another human, sporozoites are injected with bite Mature infective stages (sporozoites) Sporozoites Parasites escape from intestine and (sporozoites) migrate to the mosquito reach the liver salivary glands through blood Liver Salivary glands The parasite reproduces Fertilisation and Mosquito host asexually in liver cells, development take bursting the cell and place in the mosquito's releasing into the blood. intestine Human host Female mosquito Gametocytes Parasites reproduce asexually takes up gametocytes Female in red blood cells, bursting the with blood meal red blood cells and causing cycles of fever and other Male symptoms. Released parasites infect new red blood cells. Sexual stages (gametocytes) develop within red blood cells \t98.\t(a)\t The rupture of RBCs results in releasing toxic \t \t \t \t(ii)\t Gametocytes are produced in RBCs of substance haemozoin, which is responsible for human beings. chill and high fever recurring after 3-4 days. \t99.\t(a)\t Wuchereria bancrofti and W. malayi. \t \t (b)\t (i)\t Sprozoites are produced in intestine of \t \t(b)\t Filarial worms block the lymphatic vessels mosquito. of lower limbs, genital organs & cause gross 202 Biology\u201312","deformities in these parts. This disease is \t108.\t Cannabis sativa or hemp plant. called elephantiasis. \t\tCannabinoids interact with cannabinoid receptors \t \t (c)\t By the bite of a female Culex mosquito. present in brain and affects cardio vascular \t100.\t(a)\t \u2018A\u2019- is responsible for transfer of sporozoite of system.. \t109.\t(a)\t Yes, because drugs have many harmful Plasmodium when it bites a person to take blood meal. effects and I do not want my friend to become addicted. \t \t(b)\t \u2018C\u2019 - Fertilization of gametes inside the \t \t(b)\t (i) Drug : Cocaine intestine of the mosquito \t \t \t Source : Erythroxylum coca \t \t \t Danger: Affects central nervous system \t \t (c)\t \u2018B\u2019 - Salivary gland of the female Anopheles mosquito, sporozoites of Plasmodium and interferes with transport of neurotransmitter dopamine \t101.\t Sporozoites of Plasmodium get into human blood \t \t (ii)\t Drug : Opioids, heroin or smack through the saliva when female Anopheles bites \t \t \t Source : Papaver somniferum or poppy \u2192 Sporozoites reproduce asexually in liver cells plant \u2192 Enter RBC \u2192 Reproduce asexually, destroy \t \t \t Danger : It slows down body functions. RBC and infect more blood cells \u2192 Later they \t \t(iii)\t Drug : Cannabinoids become male and female gametophytes in \t \t \t S\t ource : Cannabis sativa different RBC\u2019s \u2192 If a mosquito bites again the \t \t \t Danger : Affects cardiovascular system gametophytes enter mosquito's intestine where \t \t (c)\t I can suggest my principal to organize poster they fertilize \u2192 Sporozoites are formed and enter making competitions, expert talk, street plays salivary glands of mosquito. etc., to make youth aware of drug abuse. \t110.\t (a)\t Yes, as a friend I should understand and \t102.\t Plasmodium falciparum. Stage is sporozoite. For support him as my friend feels lonely. life cycle-refer answer no. 96.\t \t \t(b)\t T\t eenage group is curious, adventurous, looks for excitement and experimentation. \t103.\t B-lymphocytes and T-lymphocytes. \t \t (c)\t (i) A\u0007 void undue peer pressure in education \t\tB-cells produce pathogen specific antibodies and & provide counseling \t \t (ii)\t Seeking help from parents & peers or is responsible for humoral immunity whereas taking professional and medical advice. T-cells help the B-cells to produce antibodies and \t111.\t Activities organized by students can be any of the is responsible for cell mediated immunity. following: \t\tPoster making, slogan writing, essay writing, \t104.\t(a)\t Sneezing with running nose, watery eyes and processions, display of banners, highlighting difficulty in breathing its illeffects during assembly, power-point presentation on harmful effects of tobacco. \t \t(b)\t Allergens cause body to release IgE type of \t\tActivities organized by school can be any of the antibodies. following: Seminars, workshops, talks-by doctors, counselors, psychologists, government officials, \t \t (c)\t Antihistamine, adrenalin and steroids vigilant supervision, and value education \t105.\t (a)\t Tetanus antitoxins through class teachers. \t \t(b)\t The injection contains preformed antibodies \t\tThis will help in bringing about awareness to prevent diseases associated with smoking and which act on the pathogen immediately to provide alternatives to help the smokers to quit provide protection. smoking. \t112.\t(a)\t Yes, I would report to authorities because \t \t (c)\t Injection is tetanus and it provides passive cannabinoids are classified under drugs and immunity. use of drugs is illegal. \t \t(b)\t Cannabinoids are obtained from Cannibis \t106.\t Virus enters in macrophages \u2192 RNA genome sativa. replicates to form viral DNA with help of reverse \t \t (c)\t The cannabinoids bind to cannabinoid transcriptase \u2192 Viral DNA gets incorporated into receptors in brain and affect cardio-vascular host cells\u2019 DNA to produce virus particles \u2192 HIV system. enters into helper T lymphocytes and produces \t113.\t Female mosquito picks up Plasmodium when progeny virus \u2192 New viruses are released in the they are in gametocyte stage. blood and attack other helper T lymphocytes \u2192 \t\tWhen a female Anopheles mosquito bites This leads to progressive decrease in the number an infected person, these gametocytes enter of helper T lymphocytes and the persons suffers from loss of immunity. \t107.\t(a)\t These tests are conducted to detect use of banned drugs and to ensure the fair game. \t \t(b)\t Authorities look for cannabinoids, cocaine, coca alkaloid, coke, crack, hashish, charas, ganja, hemp plant extract \t \t (c)\t Cannabis, Atropa, Erythroxylum, Datura \b (Any two) Human Health and Diseases \u2009203","the mosquito\u2019s body and undergo further \t116.\t(a)\t (i) Sporozoite\t (ii)\t Gametocyte development. The parasites multiply within \t \t(b)\t Sexual reproduction in mosquito gut, asexual them to form sporozoites that are stored in their reproduction in liver cells and RBC of human. salivary glands. When these mosquitoes bite a human, the sporozoites are introduced into his\/ \t \t (c)\t Haemozoin is the toxin which causes her body. appearance of symptoms of malaria in \t114.\t Plasmodium gain entry into human body at humans. The bursting of RBCs and release sporozoite stage. These sporozoites initially multiply within the liver cells and then attack the of toxin in blood after each cycle of asexual red blood cells (RBCs) resulting in their rupture. Rupturing of RBC release a toxin haemozoin reproduction in blood cell causes periodic which causes chills. Some of them attain sexual stage and become gametocytes in RBCs which reappearance of symptoms. are then passed to mosquito upon biting. \t117.\t(a)\t Sporozoite when enters into human body enters liver cell and multiplies asexually. \t115.\t(a)\t (i) Elephantiasis : Wuchereria bancrofti \t \t (ii)\t Ringworm: Microsporum, Trichophyton and After few cycles it enters into RBC. Upon Epidermophyton rupturing of RBC, it releases the toxin \t \t(iii)\t Amoebiasis: Entamoeba histolytica haemozoin due to which the symptoms appear \t \t(b)\t Public hygiene can help to control the water after many days. and food borne diseases such as typhoid, ascariasis and amoebiasis and in certain \t \t(b)\t Plasmodium falciparum. cases air borne diseases too. \t118.\t Pathogen: Ascaris lumbricoides \t\tOrgan affected : Intestinal passage is blocked. \t\tSymptoms: \t \t (i)\t Internal bleeding \t \t (ii)\t Muscular pain \t (\tiii)\tFever \t \t \t Mode of transmission: Through conta-minated water, food and vegetables. \t119.\t(a)\t Sporozoite stage, when an infected mosquito bites a human body. \t \t(b)\t When the mosquito bites human, sporozoites are injected with bite Parasites (sporozoites reach the liver through blood) The parasite reproduces asexually in liver cells, bursting the cell and releasing into the blood. Parasites reproduce asexually in red blood cells, bursting the red blood cells and causing cycles of fever and other symptoms. Released parasites infect new red blood cells. \t \t (c)\t Refer answer no. 114. \t122.\t(a)\t Colostrums provides passive imm-unity, \t120.\t Refer answer no. 46. direct antibodies are transferred from mother \t121.\t Functional difference between B-cells and to new born via colostrums and vaccines T-Cells\t B-cells T-Cells are in the form of living or dead microbes They provide humor- They provide cell medi- or their proteins which when introduced in al response ated response body activates active immune system of the They produce an- T-cells themselves do body. Body starts producing antibodies and tibodies when they not secrete antibodies protecting from further infections. encounter with any but help B cells produce \t \t(b)\t (i) IgA\t (ii)\t IgE antigen them. \t123.\t Bone marrow and thymus are called lymphoid organs because here immature lymphocytes 204 Biology\u201312","differentiate into antigen sensitive lymphocytes. \t \t(ii)\t Such drugs increase muscle strength B-cells mature in bone marrow and T-cells \t \t(iii)\tIf such tests are not conducted, it may be mature in thymus. unfair for those who do not consume such \t124.\t (a)\t A is antigen binding site. drugs.\t \t \t(b)\t This molecule is made up of two heavy chains \t131.\t (i)\t Avoid undue peer pressure \t \t(ii)\t Education and two light chains. \t \t(iii)\tCounselling \t \t(iv)\t Seeking help from parents and pears \t125.\t a-Antigen binding site, b- Light peptide chain, \t \t(v)\t Looking for danger signs c- Heavy peptide chain \t \t(vi)\t Seeking professional and medical help. \t \t(a)\t Antibody is an immunoglobulin \t132.\t(a)\t In our body, cell growth and differentiation \t \t(b)\t B-Cells is highly controlled and regulated. In cancer \t \t (c)\t Humoral immune response \t126.\t(a)\t (i) Snake bite cells, there is breakdown of these regulatory \t \t(ii)\t If a person is infected with deadly microbes mechanisms. Normal cells show a property such as tetanus causing bacteria. This is passive immunization. called contact inhibition by virtue of which \t \t \tSuch immunization is given when quick contact with other cells inhibits their response is required to protect the body from deadly antigens. uncontrolled growth. \t \t(b)\t Active immunization, the body responds and \t \t(b)\t \u03b1 Interferon is biological response medfliers, produces antigen specific antibodies when which activates the immune system and helps weakened antigens are introduced in body. in destroying tumour. \t127.\t HIV attacks macrophage when it gains entry into human body. 133.\t (a)\t (i) Morphine \t \t (ii)\t Lysergic acid diethyl amides (LSD). \t\tVirus enters macrophage \u2192 It uses reverse transcriptase enzyme to produce viral DNA in \t \t(b)\t Cocaine has a potent simulating action on the cell \u2192 The viral DNA gets incorporated into central nervous system which produces a sense host genome and replicates to produce viral DNA \u2192 New virus are produced within cells, thus of euphoria and increased energy. Excessive macrophage acts as virus factory. Virus enters helper T-lymphocytes and produces its progeny dosage of cocaine causes hallucinations. after destroying the lymphocyte \u2192 The cycle continues and T-lymphocytes number decreases \t134.\t \u2022\t Amoebiasis (Amoebic dysentery), Entamoeba which causes immune deficiency in the body. histolytica, constipation \/ abdominal pain \/ \t128.\t(a)\t Coat \u2018A\u2019 is made up of protein. cramps \/ stools with excess mucus \/ blood clots \t \t(b)\t The enzyme \u2018B\u2019 is reverse transcriptase, \u2018C\u2019 is (Any three symptoms), Housefly\b viral DNA. \t \t (c)\t The host cell \u2018D\u2019 is macrophage. \t \t \u2022\t Ascariasis, Ascaris, internal bleeding\/ \t \t(d)\t The new viruses \u2018E\u2019 subsequently attack muscular pain \/ fever \/ anaemia \/ blockage macrophages and helper T-lymphocytes. of intestinal passage (Any three symptoms), \t129.\t(a)\t These viruses have oncogenic genes Housefly\b \t \t(b)\t The proto-oncogenes become oncogenic \t \t \u2022\t Typhoid, Salmonella typhi, high fever \/ and become malignant. These cells grow weakness \/ stomach pain \/ constipation\/ very rapidly, invading and damaging the surrounding normal tissues. As these cells headache \/ loss of appetite (Any three actively divide and grow, they also starve the normal cells by competing for vital nutrients. symptoms), Housefly Cells sloughed from such tumors reach distant sites through blood, and wherever \t\t (Any one of the above three) they get lodged in the body, they start a new tumor there. \t\t OR \t130.\t Yes, the dope test should be conducted because \t \t(a)\t Adolescents are easily affected by ( vulnerable many sports persons take drugs such as steroids, to) peer pressure \/adventure \/curiosity \/ diuretics etc. to: excitement \/ experimentation \/ media (Any \t \t (i)\t Enhance their performance in sports & promote aggressiveness two) \t \t(b)\t Addiction-Psychological attachment to certain effects such as Euphoria \/ temporary feeling of well-being \t \t \tDependence-Tendency of the body to show withdrawal syndrome \/ symptoms if regular doses of drug \/ alcohol is abruptly discontinued\t \t135.\t (a)\t Preventive measures are. \t \t \u2013\t Ensuring use of disposable needles & \t\t syringes \t \t \u2013\t Use of condoms. Human Health and Diseases \u2009205","\u2013\t Use of HIV-free santinised blood \t \t \t\tOrgan donation is a noble cause and we should during blood transfusions. register ourself for donating organs after our \t \t \u2013\t Controlling drug abuse death which will be useless for us but can give \t \t \u2013\t Regular checkups \t \t(b)\t AIDS is caused due to HIV retrovirus. It life to others. Organs which can be donated are attacks helper T-cells & macrophages & cornea, which can give light to the life of a blind destroys immune system of a person. \t \t \t Common symptoms are person. Heart, lung, kidney can be transplanted \t \t \t \u2013 Weakness, fever, diarrhoea, \t \t \t unexplained weight loss.\t which will provide life to someone who is 5 Marks Questions suffering. \t136.\t (a)\t Vaccine is inactivated or weakened pathogen \t139.\t \u2022\t Infection is caused by sporozoites of that is inoculated into the body of the child. Plasmodium which enters the human body Vaccines activates our immune system through bite of female Anopheles mosquito. and generate memory B-cells & T-cells that recognize the pathogen quickly, on \t \t \u2022\t Sporozoites enter liver and multiply. Then subsequent exposure body produces specific they multiply within the liver cells and antibodies against the pathogen. then attack the red blood cells which causes rupture of blood cells. Toxin haemozoin is \t \t(b)\t Active Immunity and passive immunity: Refer released after rupturing of RBC. This toxin is answer no. 54. responsible for recurring chill and high fever. \t137.\t(a)\t First infection of chicken pox gives primary \t \t \u2022\t When a female Anopheles mosquito bites response and body produces antibodies an infected person, these parasites enter against chicken pox virus. Some memory the mosquito\u2019s body and undergo further cells are stored in body. Upon subsequent development. encounter with the same virus, body gives stronger secondary response due to the \t \t \u2022\t The parasites multiply within them to form memory cells formed during the first sporozoites that are stored in their salivary encounter. This type of immunity is called glands. When these mosquitoes bite a human, active immunity. the sporozoites are introduced into human body and the cycle continues. \t \t(b)\t Proteins secreted by viral infected cells which protect non infected cells from viral infection. \t\t \t For diagram refer answer no. 97. When a - interferon is given to cancer patient, 140.\t(a)\t Contact inhibition is the property of normal it activates immune system and destroys tumour. cells in which contact with other cells inhibits their further growth. Metastasis is the \t138.\t Blood group matching and tissue type matching property in which tumor cells reach distant should be done prior to the organ transplant. Our sites in the body via blood. body identifies the \u2018non-self\u2019 graft as antigen and triggers the cell mediated immune response. This \t \t(b)\t Proto oncogenes or Cellular oncogenes. then rejects the graft. \t \t \tThese genes when activated under certain condition could lead to oncogenic transformation of the cells. \t \t (c)\t Biopsy\/radiography\/CT\/MRI \t \t(d)\t 2-interferon activates immune system and destroys the tumour.\b Assertion & Reason Type Questions \t\tFor question numbers 1\u20138: Two statements \t\tReason: Different immunoglobulins molecules are given-one labelled Assertion and the other have different antigen binding properties. labelled Reason. Select the correct answer to these questions from the code (a), (b), (c) and\t \t 2.\tAssertion: Inflammatory response is produced (d) as given below. in the body after some infections. \t (a)\tBoth assertion and reason are true and reason is \t \tReason: This is one type of defence mechanism. the correct explanation of assertion. \t 3.\tAssertion: Immunity means all capacity \t (b)\tBoth assertion and reason are true but reason it of human body to resist almost all types of not the correct explanation of assertion. organisms or toxins that tend to damage the \t (c)\tAssertion is true but reason is false. \t (d)\tBoth assertion and reason are false. tissues and organs. \t 1.\tAssertion: Immunoglobulin functions as \t\tReason: Spleen is the only organ involved in antibody. immunity. \t 4.\tAssertion: A cholera patient is given glucose, electrolytes and water. 206 Biology\u201312","Reason: These plasmolyse the disease causing \t\tReason: A healthy person acquires the infection germs. by inhaling the droplets\/aerosols released by an infected person. \t 5.\tAssertion: Smack is a by-product of heroin synthesis. \t 8.\tAssertion: Proto-oncogenes are cellular genes required for normal growth. \t\tReason: Heroin is an opium alkaloid. \t 6.\tAssertion: Smoking causes oxygen deficiency in \t\tReason: Under normal conditions they could lead to the oncogenic transformation of the cell. the body. \t\tReason: Carbon monoxide when inhaled while \t 1.\t(b)\t Answers 5.\t (d) \t 6.\t(a)\t smoking, combines with haemoglobin to form 2.\t (a)\t 3.\t (c)\t 4.\t (c)\t chemically stable compound. 7.\t (b)\t 8.\t (c) \t 7.\tAssertion: Streptococcus pneumoniae and Haemophilus influenzae are responsible for causing infectious disease in human beings. Case Based Questions \t \t (b)\t Active immunity- Vaccination against corona virus. \t 1.\tRead the following and answer any four questions from(i) to (v) given below: \t \t (c)\t Active immunity- Administration of antidiphtheria serum in patient. \t\tTanya was 4 years old when she get infected with chicken pox. It took her around 2 weeks to \t \t (d)\t Passive immunity- Foetus having recover completely. Now Tanya is 5 years old so mother's milk. her mother got her vaccinated few days back for DPT (5th dose) as per immunisation program. \t \t(v)\t Assertion: A person recovered from measles Recently she was playing with her friend in develops an active immunity against this the garden when her friend accidently fell on infection. iron pipe and badly bruised her elbow. She was taken to the hospital where doctor gave her ATS \t \t \t Reason: In active immunity, person's own injection and painkillers. Based on the these cells develop antibodies in response to information, answer the following questions. infection. \t \t (i)\t Select the correct statement. \t \t(a)\t Both assertion and reason are true and reason \t \t (a)\t Tanya has developed natural active is the correct explanation of assertion. immunity against chicken pox. \t \t(b)\t Both assertion and reason are true but reason is not the correct explanation of assertion. \t \t (b)\t Tanya has developed artificial active immunity against DPT. \t \t (c)\t Assertion is true but reason is false. \t \t (c)\t Tanya\u2019s friend has developed artificial \t \t(d)\t Both assertion and reason are false. passive immunity against tetanus. \t 2.\tRead the following and answer any four \t \t (d)\t All of these questions from(i) to (v) given below: \t \t(ii)\t Which of the following do you think is an \t\tIn a study to test a new vaccine against a viral example of natural passive immunity? disease, mouse model testing is done. In this process, mice are vaccinated and their blood \t \t (a)\t Administration of AGS (anti gas gangrene samples were tested. Mice developed mild disease serum) in a person. symptom. After few days those mice were again infected with the virus. This time they \t \t (b)\t Transfer of IgA antibodies from mother do not show any disease symptoms. Their blood to baby through mother\u2019s milk. samples were tested. Two graphs show antibody concentration for the first and second infection \t \t (c)\t A person recovered from viral infection. in mice blood. \t \t (d)\t A child vaccinated for polio. \t (\tiii)\tWhich of the following is true for active immunity? \t \t (a)\t It provides immediate relief. \t \t (b)\t It is temporary, not long lasting. \t \t (c)\t It has no side effects. \t \t (d)\t None of these \t \t(iv)\t Select the incorrect match. \t \t (a)\t Passive immunity- IgG antibodies crossing placental barrier to reach foetus. Human Health and Diseases \u2009207","Based on the above information, answer the persistent diarrhoea. He developed constant following questions. low grade fever and used to catch opportunistic \t \t (i)\t R and S in the given graphs indicate \t \t (a)\t IgM and IgA respectively. infection. When he consulted a doctor, he got \t \t (b)\t IgM and IgG respectively. \t \t (c)\t IgG and IgM respectively. himself tested for HIV in his blood and finally \t \t (d)\t IgG and IgE respectively. \t \t(ii)\t Which form of pathogen is used in vaccination? diagnosed with AIDS. \t \t(a)\t Inactivated and weakened pathogenic \t\tBased on the above information, answer the antigens. following questions. \t \t(b)\t Preformed antibodies \t \t (i)\t Select the incorrect statement. \t \t (c)\t Hyperactive and strong pathogen \t \t(d)\t Activated and strong pathogenic antigens \t \t (a)\t December 10 is recalled as World AIDS \t (\tiii)\tWhich of the following is incorrect for R? Day. \t \t (a)\t It is found in blood, lymph and intestine. \t \t (b)\t It is unable to cross the placental barrier. \t \t (b)\t AIDS is a disorder of cell mediated \t \t (c)\t It is a monomer. immune (CMI) system of the body. \t \t (d)\t It is the most abundant class of Ig. \t \t(iv)\t How does vaccination work? \t \t (c)\t A I D S i s c a u s e d b y H u m a n \t \t (a)\t The dead pathogen stays in the body Immunodeficiency virus. and constantly stimulates the immune \t \t (d)\t AIDS infections were detected in India for system. the first time in prostitutes of Chennai, \t \t (b)\t The immune system produces antibodies Tamil Nadu in 1986. which stay in the blood. \t \t(ii)\t How do you think Danish got AIDS infection? \t \t (c)\t Memory lymphocytes remain in the body to fight off any future infection with the \t \t (a)\t Sexual intercourse with an infected same pathogen. partner \t \t (d)\t All of these. \t \t (b)\t Sharing towel with infected friend \t \t(v)\t Assertion: Mice do not show any disease \t \t (c)\t Use of contaminated needles and syringes symptoms during second exposure to the to inject drugs pathogenic virus. \t \t (d)\t Through transfusion of HIV infected blood \t \t \tReason: The antibody production is accelerated and more intense during \t (\tiii)\tHow can AIDS can be diagnosed? secondary immune response. \t \t (a)\t Widal test\t (b)\t ELISA test \t \t (a)\t Both assertion and reason are true and reason is the correct explanation of \t \t (c)\t Ames test\t (d)\t Pap\u2019s test assertion. \t \t(iv)\t How can AIDS be prevented? \t \t (b)\t Both assertion and reason are true but \t \t (a)\t Having protected sex by use of condoms reason is not the correct explanation of \t \t (b)\t Blood tests of blood donor before assertion. transfusion to check for the presence of \t \t (c)\t Assertion is true but reason is false. AIDS virus. \t \t (d)\t Both assertion and reason are false. \t 3.\tRead the following and answer any four \t \t (c)\t Use of disposable needles and syringes for injecting medicines and vaccination questions from (i) to (v) given below: \t\tA group of teenagers was involved in drug abuse. \t \t (d)\t All of these They used syringes and needles to inject drugs. \t \t(v)\t Select the correct statement for AIDS virus. They indulged in this bad habit when they became adults. Administration of drug through \t \t (a)\t It is rhomboid in shape with a diameter needles became daily routine for them. Danish of 10-15 cm. was the most active drug abuser amongst them and used to take drugs in high profile parties. In a \t \t (b)\t It genome consists of ds DNA. span of time he started losing weight and suffered \t \t (c)\t It contains reverse transcriptase enzyme. \t \t (d)\t Its envelope consists of lipid bilayer and three protein coats. A\t ns.\t 1.\t (i)\t (d)\t (ii)\t (b) \t \t \t(iii)\t (c)\t (iv)\t (c) \t \t \t (v)\t (a) \t \t 2.\t (i)\t (c)\t (ii)\t (a) \t \t \t(iii)\t (b)\t (iv)\t (d) \t \t \t (v)\t (a) \t \t 3.\t (i)\t (a)\t (ii)\t (c) \t \t \t(iii)\t (b)\t (iv)\t (d) \t \t \t (v)\t (c) \b qqq 208 Biology\u201312","8 Microbes in Human Welfare Topics Covered 8.2\t Microbes in Industrial Products \t8.1\t Microbes in Household Products\t 8.4\t Microbes in production of Biogas \t8.3\t Microbes in Sewage Treatment\t 8.6\t Microbes as Bio-Fertilisers 8\t .5\t Microbes as Bio-Control Agents\t C hapter map MICROBES IN HUMAN WELFARE Domestic Sewage Treatment Biogas Bio-Fertiliser Bio-control Agents 1.\tPrimary \u2022 Methanogens \u2022 Bacteria \u2022 Ladybirds beetles 2.\tSecondary \u2022 Fungi \u2022 Dragonflies \t \u2022 Flocs \u2022 Cyanobacteria \u2022 Trichoderma \t \u2022 BOD \u2022 Baculovirus \t \u2022 Inoculum \u2022 Nucleopolyhedro virus \u2022 Beverages : Distillation, without Distillation Useful Microbes \u2022 Antibiotics: Penicillium notatum \u2022 Symbiotic bacteria-Rhizobium \u2022 Organic Acids and Alcohol: Aspergillus niger \u2022 Non-symbiotic bacteria-Azospirillum \u2022 Enzymes : Lipase, Protease, Pectinase \u2022 Glomus Fungi \u2022 Bioactive Molecules: Cyclosporin A, Statins \u2022 Cyanobacteria 1. Lactobacillus 2. Saccharomyces 3. Propioni-bacterium \u2022 LAB \u2003 cerevisiae Sharmanii Topic 1. Microbes in Household Products Various microbes or their products are used in \u2022\t Other microbes help in the fermentation of fish, households in our daily life. soyabean, bamboo shoots and palm sap to make toddy. Examples are: \u2022\t Lactobacillus converts lactose of milk to lactic acid \u2022\t Propionibacterium sharmanii is used to make Swiss which imparts sour taste to curd. It also increases cheese. This bacteria is responsible for large holes in cheese. These holes are formed due to formation vdiistaeamsien-caBu1s2ining curd and controls the growth of of carbon dioxide during ripening of cheese. bacteria in our stomach. \u2022\t A fungi Penicillium roqueforti is used to make \u2022\t Saccharomyces cerevisiae also known as baker\u2019s Roquefort cheese which has characteristic flavour yeast ferments the dough of bread. The puffing up and coloured stripes in cheese. of dough is due to the production of carbon dioxide. \u2022\t Some bacteria are responsible for fermentation of batter for idli and dosa. Topic 2. Microbes in Industrial Products Microbes used in industry are used to obtain various Fermented Beverages products on large scale. These microbes are cultured \u2022\t Saccharomyces cerevisiae also called brewer\u2019s yeast in large containers called fermenters. is used to make fermented beverages like wine, beer, 209","brandy, whiskey, rum. Beer and wine are produced Uses of Antibiotics and its Disadvantages without distillation and whiskey, brandy and rum are produced by distillation. Antibiotics are used to kill large pathogenic group and fight against various diseases. In limited quantity \u2022\t S. cerevisiae is also used to make ethanol from antibiotics cause no damage like allergy to host. malted cereals and fruit juices. Antibiotics are so efficient that pathogen is killed before it mutates and becomes resistant to it, but if \u2022\t Penicillium notatum is used to make antibiotic used unnecessarily, bacteria may become resistant to called penicillin. antibiotics. Antibiotics are ineffective in case of viral infections. \u2022\t Antibiotics are commonly used to treat diseases such as plague, whooping cough (kali khansi), diphtheria Classes of Antibiotics (gal ghotu) and leprosy (kusht rog). Antibiotics are basically classified into five classes: \u2022\t Aspergillus niger is used to produce citric acid. \u2022\t b-Lactam: They inhibit the cell wall formation, e.g. \u2022\t Acetobacter aceti is used to produce acetic acid. Penicillin. \u2022\t Clostridium butylicum is used to produce butyric \u2022\t Aminoglycosides: Aminoglycosides are derived acid. from different species of\u00a0Streptomyces. These antibiotics stop bacteria to make proteins. These are \u2022\t Lactobacillus is used to produce lactic acid. injected in the body, e.g. Gentamicin \u2022\t Streptococcus is used to produce streptokinase. It \u2022\t Quinolone: These are synthetic broad spectrum acts as clot buster. antibiotic drugs, e.g. Ciprofloxacin \u2022\t Some microbes are used to make enzymes such as \u2022\t Sulfonamides: Sulfonamides are synthetic lipase, which is added to detergents to remove oily antimicrobial agents that contain the sulfonamide stains. group. These antibiotics inhibit the growth of bacteria but do not kill them. e.g. Sulfamethoxazole. \u2022\t Pectinase and protease is used to make bottled juice clear. \u2022\t Glycopeptides: They bind to the amino acids within the cell wall preventing the addition of new \u2022\t Trichoderma polysporum produces Cyclosporin-A, units to the peptidoglycan, e.g. Vancomycin. which is a bioactive molecule used as immunosuppressive agent in case of organ Judicious use of Antibiotics transplant. \u2022\t \u201cJudicious use\u201d is using a drug appropriately and \u2022\t Monascus purpureus produces statins, which are only when necessary, intake of optimal dose for blood cholesterol lowering agents. limited period of time. Antibiotics \u2022\t Overuse of antibiotics is responsible for increasing \u2022\t These are the medicines which kill or slow down the drug resistance in bacteria. Such resistant bacteria are called hard to kill \u2018bad bugs\u2019. growth of bacteria. \u2022\t People often misuse antibiotics by self-prescription. \u2022\t Penicillin an antibiotic was the first to be discovered \u2022\t Even doctors sometimes do not prescribe correct by Alexander Fleming in 1928. dosage which should be according to weight and \u2022\t Antibiotics prevent multiplication of bacteria by history of prior use. interfering with bacterial metabolism of cell wall \u2022\t These drugs are not of any use when person is formation in bacteria. Immune system of host body suffering from common cold, flu or other viral then prevents the further bacterial infection in body. infections but when used later they can become ineffective for bacterial disease. \u2022\t Some antibiotics can be used to treat a wide range of infections and are known as broad-spectrum\u00a0antibi- \u2022\t Lack of education, awareness and expectation to get otics and some are used against few types of bacteria well soon lead to overuse of drugs. and are called\u00a0narrow-spectrum\u00a0antibiotics. Topic 3. Microbes in Sewage Treatment \u2022\t Household waste water of cities and towns is called \u2022\t Before disposing off in rivers or other water bodies, sewage. sewage water must be treated. Treatment is done in sewage treatment plants (STP) in two stages: \u2022\t Sewage water contains human excreta as major component along with other organic matter like food `` Primary treatment particles. It also contains pathogenic microbes and various toxins. \t \u2022\t Physical removal of large and small particles is done by filtration and sedimentation. 210 Biology\u201312","\u2022\t Solids settled down is called primary sludge and \t \u2022\t Once the BOD is reduced, effluent is taken to supernatant is called effluent. Effluent is then settling tank where flocs are allowed to settle. subjected to secondary treatment. This sediment is called activated sludge. It is `` Secondary treatment: Biological treatment used as inoculum in aeration tanks. happens here. \t \u2022\t Rest of sludge is taken to anaerobic sludge \t \u2022\t In aeration tank, bacteria and fungus grow by digesters, anaerobic bacteria digests bacteria and constant aeration due to vigorous agitation of fungi and produce gases like hydrogen sulphide, water. Bacteria and fungus forms mesh like carbon dioxide and methane (collectively called structure called flocs which consumes major as biogas). Biogas is inflammable and is used as part of organic matter present in effluent. source of energy. \u2022\t Treated water with reduced biological oxygen demand is now released in rivers and streams. Primary treatment Secondary treatment Domestic Filteration Sedimentation Effluent Aeration Settling Flocs settle sewage Grit removed down water Floating Primary sludge tank tank debris inoculum Activated Anaerobic sludge removed sludge digester Biogas \u2022\t In India, The Ministry of Environment and Effluent released in rivers and streams Forests (MOEF) has initiated Ganga Action Plan and Yamuna Action Plan to save major sewage discharge in these rivers. Under these plans, rivers of our country from pollution due to direct large number of sewage treatment plants have been proposed so that only treated sewage may be discharged in the rivers. Topic 4. Microbes in Production of Biogas \u2022\t Biogas is the mixture of gases mainly methane \u2022\t These bacteria called methanogens are present which is produced by microbes and is used as fuel. in anaerobic sludge and rumen of cattle. Major Other gases include carbon dioxide and hydrogen. methanogen is Methanobacterium which is present in the gut of cattle and is therefore present in excreta \u2022\t Such microbes use cellulose as digesting substrate of cattle. Under anaerobic conditions they produce and produce methane along with carbon dioxide biogas. and hydrogen. Biogas is produced due to action of anaerobic bacteria methanogens on cellulosic substrate. Slurry of cattle Floating Outlet for biogas dung and water gas-holder Gas valve Outlet Overflow tank Mixing tank Inlet Level Inlet pipe Spent Slurry Outlet pipe Dung and water Partition wall Underground digester tank Support for pipe Floating gas-holder type bio-gas plant Microbes in Human Welfare \u2009211","\u2022\t The biogas plant is made up of a concrete tank with the depth of 10-15 feet. This tank is fed with slurry made up of cow dung and water. A floating dome collects gas as is produced from slurry. \u2022\t Used slurry is used as manure in farm lands. \u2022\t Technology of biogas was developed in India by the combined efforts of Indian Agricultural Research Institute (IARI) and Khadi and Village Industries Commission (KVIC). Topic 5. Microbes as Bio-control Agents \u2022\t Bio-control agents are the living organisms which `` Trichoderma, a fungus is used to control soil are used to control pests and disease causing borne plant pathogens. organisms. With the use of bio-control agents, the use of toxic and polluting chemicals like insecticides `` Baculovirus are used to control insects and and pesticides have been reduced. arthropods \u2022\t Examples of bio-control agents are given below: `` Nucleopolyhedro virus a narrow spectrum species-specific biocontrol agent is used to kill `` Ladybirds beetles with red and black markings insects. There is no negative impact on plants, are used to control aphids mammals, birds, fish etc. Only target organisms are harmed. `` Dragonflies are used to control mosquitoes \u2022\t Sometimes bio-control agents are used along with `` Spores of bacteria Bacillus thuringiensis traditional methods to control insects and pests. (Bt) are used as powder to control butterfly This is called integrated pest management (IPM). caterpillars which kill larvae. Topic 6. Microbes as Bio-fertilisers `` Glomus fungi is a mycorhiza which absorbs phosphorus from soil for the plants with which \u2022\t In organic farming, microbes are powerful agents they have symbiotic association. which are used as eco-friendly fertilizers. \u2022\t Such associations also help plants to resist from \u2022\t These bio-fertilizers fix nitrogen in the soil. root-borne pathogens, increase tolerance towards salinity and drought. This also helps in overall plant \u2022\t Various bacteria, fungi and cyanobacteria are used growth and development. as biofertilizers. \u2022\t Cyanobacteria like Anabaena, Nostoc, Oscillatoria `` Rhizobium is a symbiotic bacteria which thrives are also used as bio-fertilizers. in soil but when they are in symbiotic association with roots of leguminous plants, fix atmospheric \u2022\t They are used in paddy fields, also adds organic nitrogen. matter in soil and increases fertility by replenishing soil nutrients. `` Free living non-symbiotic bacteria like Azospirillum and Azotobacter also fix nitrogen in soil. EXERCISE I.M\t ultiple Choice Questions \t4.\tThe primary treatment of waste water involves the removal of: \t 1.\tThe vitamin whose content increases following the conversion of milk into curd by lactic acid \t\t(a)\t Dissolved impurities\t (b)\t Stable particles bacteria is: \t\t(c)\t Toxic substances\t (d)\t Harmful bacteria. \t\t(a) Vitamin C\t (b)\t Vitamin D \t5.\tBOD of waste water is estimated by measuring the amount of: \t\t(c) Vitamin B12\t(d)\t Vitamin E \t2.\tWastewater treatment generates a large quantity \t\t(a)\t Total organic matter of sludge, which can be treated by: \t\t(b)\t Biodegradable organic matter \t\t(a)\t Anaerobic digesters\t (b)\tFloc \t\t(c)\t Oxygen evolution \t\t(c)\tChemicals\t (d)\t Oxidation pond. \t\t(d)\t Ixygen consumption. \t3.\tMethanogenic bacteria are not found in: \t 6.\tWhich one of the following alcoholic drinks is produced without distillation? \t\t(a)\t Rumen of cattle\t (b)\t Gobar gas plant \t\t(a)\tWine\t (b)\tWhisky \t\t(c)\t Bottom of water-logged paddy fields \t\t(c)\tRum\t (d)\tBrandy \t\t(d)\t Activated sludge. 212 Biology\u201312","7.\tThe technology of biogas production from cow \t\t(b)\t Absorb pathogenic bacteria present in waste dung was developed in India largely due to the water while sinking to the bottom of the efforts of: settling tank \t\t(a)\t Gas Authority of India \t\t(c)\t Be discarded and anaerobically digested \t\t(d)\t Absorb colloidal organic matter. \t\t(b)\t Oil and Natural Gas Commission II. Fill in the blanks \t\t(c) \tIndian Agricultural Research Institute and \t1.\t____ is the association of fungi with root. Khadi & Village Industries Commission \t2.\t____ produces _____ in leguminous crops. \t\t(d) \tIndian Oil Corporation. III. True or False \t1.\tBiofertilizers are inorganic minerals which bring \t8.\tThe free-living fungus Trichoderma can be used for: about enrichment of soil. \t2.\tAnabaena is an excellent fertilizer for rice. \t\t(a)\t Iilling insects \t3.\tIndian soils are usually poor in organic matter \t\t(b)\t Biological control of plant diseases and in nitrogen. \t4.\tLegumes are fruits of plants of the pea family. \t\t(c)\t Controlling butterfly caterpillars \t5.\tThe bacterium Bacillus thuringensis produces \t\t(d) \tOroducing antibiotics proteinaceous toxins. \t9.\tWhat would happen if oxygen availability to \tIV.\tMatch the items in Column \u2018I\u2019 and Column \u2018II\u2019. activated sludge flocs is reduced? \t\t(a)\tIt will slow down the rate of degradation of organic matter \t\t(b)\t The center of flocs will become anoxic, which Column I Column II would cause death of bacteria and eventually (i) Lady bird (a) Methanobacterium (ii) Mycorrhiza (b) Trichoderma breakage of flocs. (iii) Biological control (c) Aphids (iv) Biogas (d) Glomus \t\t(c)\tFlocs would increase in size as anaerobic bacteria would grow around flocs. \t\t(d)\t Protozoa would grow in large numbers. \t10.\tMycorrhiza does not help the host plant in: 1 Mark Questions \t\t(a) \tEnhancing its phosphorus uptake capacity \t\t(b) \tIncreasing its tolerance to drought \t1.\tWrite the scientific name of the microbe used for \t\t(c)\t Enhancing its resistance to root pathogens fermenting malted cereals and fruit juices.\t \t\t(d) \tIncreasing its resistance to insects. \b [Delhi 2011] \t11.\tWhich one of the following is not a nitrogen-fixing \t2.\tMention the role of cyanobacteria as a biofertiliser. organism? \b[All India 2012] \t\t(a) Anabaena\t(b)\t Nostoc \t3.\tWhy do we add an inoculum of curd to milk for curding it?\b [All India 2015 C] \t\t(c) Azotobacter\t(d)\t Pseudomonas \t4.\tHow is lactic acid bacteria beneficial to us other \t12.\tBig holes in Swiss cheese are made by a: than helping in curdling the milk? \t\t(a)\t A machine \b [All India 2015 C] \t\t(b)\t A bacterium that produces methane gas \t5.\tName the nutrient that gets enhanced while curdling of milk by Lactobacillus.\b[Delhi 2013 C] \t\t(c)\tA bacterium producing a large amount of carbon dioxide \t6.\tName the gas released and the process \t\t(d)\tA fungus that releases a lot of gases during responsible for puffing up of the bread dough its metabolic activities. when Saccharomyces cerevisiae is added to it. \t13.\tThe residue left after methane production from cattle dung is: \b [All India 2013 C] \t7.\tName the metabolic pathway associated with the \t\t(a)\tBurnt rising of dough in making bread. What makes the \t\t(b)\t Burried in land fills dough rise?\b [Delhi 2012 C] \t\t(c)\t Used as manure \t8.\tMilk starts to coagulate when lactic acid bacteria (LAB) is added to warm milk as a starter. \t\t(d) \tUsed in civil construction. \t14.\tMethanogens do not produce: Mention any other two benefits LAB provides. \t\t(a) Oxygen\t (b)\tMethane \b[All India 2009] \t\t(c) Hydrogen sulfide\t (d)\t Carbon dioxide. \t 9.\tName the enzyme produced by Streptococcus and \t15.\tActivated sludge should have the ability to settle its action (after being modified). quickly so that it can: \b [All India 2013 C] \t\t(a)\t Be rapidly pumped back from sedimentation \t 10.\tWhich one of the following is the baker's yeast tank to aeration tank used in fermentation? Microbes in Human Welfare \u2009213","Saccharum barberi, Saccharomyces cerevisiae, \t26.\tMention a product of human welfare obtained Sonalika.\b [All India 2009] with the help of each one of the following microbes: \t 11.\tWhy is sewage water treated until the BOD is reduced? Give a reason. \b [Delhi 2010 C] \t\t(a)\tLAB\t\t \t 12.\tBOD of two samples of water A and B were 120 \t\t(b)\t Saccharomyces cerevisiae mg\/L and 400 mg\/L respectively. Which sample is \t\t(c)\t Propionibacterium sharmanii more polluted? \b [Foreign 2009] \t\t(d)\t Aspergillus niger \b[Delhi 2013, 2015] \t 13.\tGiven below are a few impurities in urban waste water. Select two colloidal impurities: \t27.\tName the enzyme produced by Strepto-coccus bacterium. Explain its importance in medical \t\tAmmonia, faecal matter, silt, bacteria, calcium. sciences.\b[All India 2011] \b [All India 2009 C] \t28.\tExplain the different steps involved during \t 14.\tWhat makes the Nucleopolyhedrovirus a primary treatment phase of sewage. desirable biological co ntrol agent? \b [All India 2013] \b [All India 2012 C, 2013 C] \t 15.\tState one reason for adding blue-green algae to \t29.\tName the group of organism and the substrate they act on to produce biogas.\b [Delhi 2009] the agricultural soil.\b [All India 2011 C, 2014 C] \t30.\tName a genus of baculovirus. Why are they \t 16.\tName any one symbiont which serves as a considered good biocontrol agents? biofertiliser. Mention its specific role. \b [All India 2016] \b [All India 2010 C] \t 17.\tWhich of the following is a free-living bacteria OR that can fix nitrogen in the soil? Spirulina, \t\tName the genus to which baculoviruses belong. Azospirillum, Sonalika.\b [Delhi 2009] Describetheirroleinthe integrated pest management programmes.\b[All India 2011] \t 18.\tWhich of the following is cynobacterium that can fix atmospheric nitrogen? Azospirillum, Oscillatoria, Spirulina.\b [All India 2009] \t31.\tName the bacterium responsible for the large holes seen in \\\"Swiss Cheese\\\". What are these \t 19.\tHow is presence of cyanobacteria in the paddy field beneficial to rice crop?\b [Delhi 2009 C] holes due to?\b [All India 2013] \t 20.\tList two advantages that a mycorrhizal associa- \t 32.\tMention the importance of Lactic acid bacteria tion provides to the plant.\b [All India 2008 C] to humans other than setting milk into curd. \t 21.\tWrite the scientific name of the microbe used for \b [Delhi 2012] fermenting malted cereals and fruit juices. \t 33.\tDuring the production of curd, a small amount \b [Delhi 2011] of curd is added as a starter to the fresh milk at a suitable temperature. Explain the changes the 2 Marks Questions milk undergoes when it sets into curd. \t22.\tName a free-living and a symbiotic bacterium \b [Delhi 2011 C] that serves as bio-fertilizer. Why are they so \t 34.\tWhy is a little curd added to milk to set it into called? \b [All India 2016] curd? Explain.\b [All India 2011 C] \t23.\tName the bioactive molecule that is used as \t 35.\tHow does addition of a small amount of curd to immuno-suppressive agent and its source fresh milk help formation of curd? Mention a nutritional quality that gets added to the curd. organism. \b [All India 2013] \b [Delhi 2010] \t24.\tBottled fruit juices are clearer as compared to \t 36.\tName the organism that causes large holes in those made at home. Explain. \b[Foreign 2015 C] 'Swiss cheese'. How are these holes caused?\b \t25.\tName the blank spaces a, b, c and d from the [Delhi 2008 C] table given below: Type of Scientific Commercial \t 37.\tName the source of streptokinase. How does this microbe name product bioactive molecule function in our body? Bacterium a Lactic acid \b [Delhi 2012] Fungus b Cyclosporin A \t 38.\tWhy are some molecules called bioactive molecules? Give two examples of such molecules. c Monascus Statin \b [All India 2011] purpureus \t 39.\tGive the scientific name of the microbes from which cyclosporin A and statin are obtained. Fungus Penicillium d Write one medical use of each one of these drugs. notatum \b [Foreign 2011] [Delhi 2011] 214 Biology\u201312","40.\tIdentify A, B, C and D in the table given below:\t \t 48.\tExplain the different steps involved during primary treatment phase of sewage. Micro-organism Product Biological Medical Activity Ailment\/ [All India 2015] Procedure \t 49.\tExplain the process of secondary treatment given to the primary effluent up to the point it shows A Streptokinase Clotbuster B significant change in the level of biological oxygen Trichoderma C D Transplant demand (BOD) in it.\b [All India 2015] polysporum surgery \t 50.\tName two groups of organisms which constitute [All India 2009 C] 'flocs'. Write their influence on the level on BOD \t 41.\tName the blank spaces, a, b, c and d in the table during biological treatment of sewage. given below: \b [All India 2014 C] \t 51.\tExplain the role of flocs in sewage treatment Type of Microbe Name Commercial \b [All India 2012 C] Product \t 52.\tDuring the secondary treatment of the primary effluent how does the significant decrease in BOD Fungus a Penicillin occur?\b [Delhi 2009] Bacterium Acetobacter aceti b \t53.\tHow do methanogens help in producing biogas? c Aspergillus niger citric acid \b [Delhi 2012] Yeast d ethanoal \t 54.\tWhy is Rhizobium categorised as a 'symbiotic bacterium'? How does it act as a biofertiliser? [Delhi 2008] \b [Delhi 2012] \t 42.\tName the blank spaces, a, b, c and d given in the \t 55.\tHow do mycorrhizae act as biofertilisers? Explain. following table: Name a genus of fungi that forms a mycorrhizal Type of Microbe Name Commercial Product association with plants.\b [Delhi 2012] Bacterium a Lactic acid \t56.\tName the microbes that help production of the following products commercially:\b Fungus b Cyclosporin A \t\t(a)\tStatin\t (b)\t Citric acid c Monascus statins purpureus \t\t(c)\tPenicillin\t (d)\t Butyric acid Fungus Penicillium d \b[All India 2017] notatum \t57.\tWrite the binomials of two fungi and mention \t43.\tName the blank spaces, a, b, c and d in the table the products\/bioactive molecules they help to given below: produce.\b[All India 2017] Type of Microbe Scientific Name Commercial \t58.\tYour advice is sought to improve the nitrogen Product content of the soil to be used for cultivation of a Bacterium a non-leguminous terrestrial crop.\b b Clot buster Aspergillus niger enzyme \t\t(a)\t Recommend two microbes that can enrich the Fungus Trichoderma soil with nitrogen. Bacterium polysporum Citric acid d \t\t(b)\tWhy do leguminous crops not require such c enrichment of the soil?\b [CBSE 2018] Butyric acid \t 59.\tHow did a citizen group called Friends of Arcata Marsh, Arcata, California, USA, help to improve [Delhi 2008] water quality of the marshland using Integrated Waste Water Treatment? Explain in four steps. \t 44.\tWhat are flocs? State their role in biological treatment of sewage.\b [CBSE 2022] \t 45.\tFarmers are often suggested to use the following \b [CBSE 2018] organisms in their crop land so as to improve the 3 Marks Questions soil fertility. \t 60.\tName the source of cyclosporin-A. How does this bioactive molecule function in our body? \t\t(i)\tRhizobium\u2003\u2003(ii) Anabaena Explain \b [CBSE 2022] \t 46.\tList the events that reduce the Biological Oxygen \b [All India 2012] Demand (BOD) of a primary effluent during \t61.\tState the medicinal value and the bioactive molecule produced by Streptococcus, Monascus sewage treatment.\b [Delhi 2016] \t47.\tDistinguish between the roles of flocs and and Trichoderma.\b[All India 2015] anaerobic sludge digesters in sewage treatment. \t62.\tWhat are methanogens? How do they help to generate biogas?\b [All India 2013, 2015] \b [Delhi 2016] Microbes in Human Welfare \u2009215","63.\tThe diagram below is that of a typical biogas \t71.\tMention the importance of microbes Streptococcus, plant. Explain the sequence of events occurring Trichoderma and Monascus in medical sciences. in a biogas plant. Identify a, b and c. \b [All India 2011 C] Gas \t 72.\tIdentify a, b, c, d, e and f in the table given below: (b) Organism Bioactive Use (i) Monascus molecule b purpureus (yeast) a (c) (a) (ii) c d Antibiotic (iii) e Cyclosporin A f (d) \t 73.\tMention the product and its use produced by each of the microbes listed below: \t\t \b[Delhi 2011] \t 64.\tHow do organic farmers control pests? Give two \t\t(a)\t Streptococcus\t examples. \t\t(b)\t Lactobacillus \t65.\tGiven below is a list of six microorganisms. State their usefulness to humans. \t\t(c)\t Saccharomyces cerevisiae\b [All India 2010] \t\t(a)\t Nucleopolyhedrovirus \t 74.\tWhat are the properties of an antibiotic? \b [All India 2010 C] \t\t(b)\t Saccharomyces cerevisiae \t 75.\tName the two different categories of microbes \t\t(c)\t Monascus purpureus naturally occurring in sewage water. Explain \t\t(d)\t Trichoderma polysporum their role in cleaning sewage water into usable \t\t(e)\t Penicillium notatum water.\b [Delhi 2012] \t\t(f)\t Propionibacterium sharmanii\b[Delhi 2016] \t 76.\tExplain the different steps involved in sewage treatment before it can be released into natural \t66.\tChoose any three microbes from the following which are suited for organic farming, which is water bodies.\t\b [Foreign 2011] in great demand these days for various reasons. \t 77.\t(a)\t How is activated slude formed during sewage treatment? Mention one application of each one chosen. \t\t(b)\t This sludge can be used as an inoculum or as \t\tMycorrhiza; Monascus; Anabaena; a source of biogas. Explain. \t\tRhizobium; Methanobacterium; \t\tTrichoderma.\b[Delhi 2013] \b [All India 2009, Delhi 2011 C] \t67.\tExplain the change fresh milk undergoes when \t 78.\tHow can sewage be used to generate biogas? a small amount of curd as starter is added to it Explain.\b [Foreign 2015] and kept at suitable temperature.[\bDelhi 2009 C] \t 79.\t(a)\t What are methanogens? \t\t(b)\tName the animals in which methanogens \t68.\tIdentify a, b, c, d, e and f in the table given below: occur and the role they play there. Scientific name Product produced Use in \b [Delhi 2014] of the organism human welfare Streptococcus Streptokinase that \t 80.\tDescribe how biogas is generated from activated was later modified a sludge. List the components of biogas. \b [All India 2013 C] \t 81.\tHow are Baculoviruses and Bacillus thuringiensis b Cyclosporin A c used as bio-control agents? Why are they preferred over readily available chemical pesticides? Monascus de purpureus f sets milk into \b [All India 2014 C] Lactobacillus curd \t 82.\tWhy should biological control of pests and pathogens be preferred to the conventional used [Foreign 2014] of chemical pesticides? Explain how the following \t 69.\t(a)\t Why are the fruit juices bought from market microbes act as biocontrol agents: clearer as compared to those made at home? \t\t(a)\t Bacillus thuringiensis \t\t(b)\tName the bioactive molecules produced by \t\t(b)\t Nucleopolyhedrovirus\b [Delhi 2008] Trichoderma polysporum and Monascus \t 83.\t(a)\tWhy do farmers prefer biofertilisers to purpureus.\b [Delhi 2013] chemical fertilisers these days? Explain. \t 70.\tWrite the source and applications of cyclosporin \t\t(b)\tHow do Anabaena and mycorrhiza act as A, streptokinase and statin.\b [Delhi 2012 C] biofertilisers?\b [Delhi 2011] 216 Biology\u201312","84.\tSecondary treatment of the sewage is also called \t87.\tWhat are bio fertilizers? Describe their role in Biological treatment. Justify this statement and agriculture. Why are they preferred to chemical explain the process.\b [All India 2017] fertilizers? \b [Foreign 2015 C] \t85.\t(a)\tOrganic farmers prefer biological control of \t88.\t(a)\t Explain the process of sewage water treatment diseases and pests to the use of chemicals for before it can be discharged into natural water bodies. the same purpose. Justify. \t\t(b)\t Give an example of a bacterium, a fungus and \t\t(b)\t Why is this treatment essential?\t an insect that are used as biocontrol agents. \b[CBSE 2018] [All India 2014] 5 Marks Questions \t89.\t(a)\tName the category of microbes occurring naturally in sewage and making it less \t86.\tDescribe the process of waste-water treatment polluted during the treatment. under the following heads: \t\t(b)\tExplain the different steps involved in the \t\t(a)\t Primary treatment. [Foreign 2016] secondary treatment of sewage. \t\t(b)\t Secondary treatment. \b \b [Foreign 2014] Answers I. Multiple Choice Questions \t13.\tFaecal matter, bacteria \t14.\tThese are species-specific, narrow spectrum \t 1.\t(c)\t 2.\t(a)\t 3.\t(d)\t 4.\t(b)\t 5.\t(d) \t 6.\t(a)\t 7.\t(c)\t 8.\t(b)\t 9.\t(b)\t 10.\t(d) insecticides and do not harm non-target \t 11.\t(d)\t 12.\t(c)\t 13.\t(c)\t 14.\t(a)\t 15.\t(c) organisms. II. Fill in the Blanks \t15.\tBlue-green algae performs nitrogen fixation and it enriches soil by increasing nitrogen content. It \t 1.\tMycorrhiza\t 2.\t Rhizobium, nodules also adds organic matter to the soil. III. True or False \t16.\tRhizobium. It fixes atmospheric nitrogen when associated with the roots of legume plants. \t 1.\tFalse\t 2.\t False\t 3.\tTrue\t 4.\tTrue\t 5.\tTrue \t17.\tAzospirillum IV. \u0007Match the items of Column I with those of \t18.\tAzospirillum Column II: \t19.\tCyanobacteria fix atmospheric nitrogen and \t(i)\t(c)\t(ii)\t(d)\t(iii)\t(b)\t(iv)\t(a) enrich soil when present in paddy fields. 1 Mark Questions \t20.\tAbsorbs phosphorus, provides resistance from root borne pathogens, increase tolerance towards \t 1.\tSaccharomyces cerevisiae salinity and drought and help in overall plant \t 2.\tCyanobacteria such as Anabaena and Nostoc are growth and development. free-living nitrogen fixing organisms. They are \t21.\tSaccharomyces cerevisiae (yeast)\t used as bio-fertilizers in paddy fields and add organic matter to the soil. 2 Marks Questions \t3.\tA small amount of inoculum contains millions \t22.\tAzospirillium, Azotobacter or Rhizobium. They of LAB, which at suitable temperature multiply enrich soil nutrients by fixing atmospheric and convert milk in to curd. nitrogen. \t4.\tLAB improves its nutritional quality by increasing \t23.\tCyclosporin A, Trichoderma polysporum vcaituasminignmBic1r2obaensdinhoeulpr s in checking disease \t 24.\tEnzyme pectinase and protease are added in gut. bottled juices to make them clear.\t \t5.\tVitamin B12 \t 25.\t(a)\t Lactobacillus\t\t \t6.\tCarbon-dioxide, fermentation \t\t(b)\t Trichoderma polysporum \t7.\tRelease of carbon-dioxide makes dough rise \t\t(c)\tFungus \t8.\tLAB improves its nutritional quality by increasing \t\t(d)\tPenicillin \t26.\t(a)\t LAB converts milk to curd vmiticarmobinesBin12oaunrdguhte. lps in checking disease-causing \t\t(b)\t Saccharomyces cerevisiae. used to make \t9.\tStreptokinase; it acts as clot buster. bread, ethanol, whiskey, brandy, beer, rum \t10.\tSaccharomyces cerevisiae etc. \t11.\tSewage water contains organic matter which \t\t(c)\t Propionibacterium Sharmanii. is used to increases BOD of water, it also contains make Swiss cheese pathogenic microbes. This organic matter reduces the dissolved oxygen in water. \t\t(d)\t Aspergillus niger is used to make citric acid \t27.\tStreptokinase. It is used as clot buster \t12.\tSample B Microbes in Human Welfare \u2009217","28.\tLarge and small particles such as paper, \t\t(c)\tFungus\t\t polythene, pebbles, soil etc. are physically \t\t(d)\tPenicillin removed by filtration and sedimentation. \t 43.\t(a) \tStreptococcus\t(b)\tFungus Initially, floating debris is removed by sequential \t\t(c)\tCyclosporin-A\t filtration. Then the grit (soil and small pebbles) \t\t(d)\t Clostridium butylicum are removed by sedimentation. Solids which settle \t 44.\tFlocs: During secondary treatment of effluent, excessive growth of aerobic bacteria and fungi form the primary sludge and the supernatant form a mass of mesh like structure called flocs. Microbes consume the major part of the organic form the effluent. matter in the effluent. This significantly reduces the BOD (biochemical oxygen demand) of the \t29.\tMethanogens effluent. \t\tThey act on cellulosic material present in organic waste like dung to produce biogas \t 45.\t(i)\t Rhizobium is a bacterium found in soil that helps in fixing nitrogen in leguminous \t30.\tNucleopolyhedrovirus. plants. It attaches to the roots of the \t\tThey are considered as good as biocontrol agents leguminous plant and produces nodules. because baculovirus is species specific, narrow- These nodules fix atmospheric nitrogen and convert it into ammonia that can be used by spectrum insecticide and has no negative impact the plant for its growth and development. on the non- target organisms. \t\t(ii)\t Anabaena plays a significant role in farming where it is used as a biofertilizer and \t31.\tPropionibacterium sharmanii. Large holes are soil stabilizer. Anabaena is a symbiotically due to production of a large amount of CO2 by related photoautotrophic cyanobacterium this bacterium. with the tiny eukaryotic water fern Azolla pinnata, in specialized leaf cavities of the fern \t32.\tLAB improves its nutritional quality by increasing under natural conditions. vitamin B12 and helps in checking disease causing microbes in our gut. \t46.\tEffluent from the primary settling tank is passed into aeration tank, then is agitated \t33.\tA small amount of inoculum contains millions mechanically and air is pumped into it. Due to of LAB, which at suitable temperature multiply this there is vigorous growth of aerobic microbes such as bacteria and fungi. They form mesh-like and during growth LAB produce acids that structure called flocs. These microbes consume major part of the organic matter in the effluent. coagulate and partially digest milk proteins hence converting milk into curd. \t34.\tRefer answer no. 33. \t35.\tRefer answer no. 33 and 32. \t36.\tPropionibacterium sharmanii. Large holes are due to production of a large amount of CO2 by this bacterium \t37.\tBacterium Streptococcus. It acts as \u2018clot buster\u2019 and is used for removing clots from the 47. Flocs \t Anaerobic Sludge blood vessels of patients who have undergone Digester myocardial infarction leading to heart attack. \u2022\t Break down organic \u2022\t B r e a k d o w n o r g a n i c \t38.\tThis is because microbes like bacteria or fungi matter aerobically matter anaerobically are used in their production. e.g. Streptokinase \u2022\t Break down organic B r e a k d o w n o r g a n i c and Cyclosporin A matter present in matter in secondary \t39.\tCyclosporin-A is obtained from Trichoderma primary effluent effluent. polysporum and is used as an immuno-suppressive \u2022\t They do not produce \u2022\t They produce biogas (mixture of methane, H2S agent in organ transplant patients. biogas. and CO2) \t\tStatins are produced by yeast Monococcus \t48.\tLarge and small particles such as paper, pupureus and is used as blood cholesterol lowering agent. polythene, pebbles, soil etc. are physically \t 40.\t(a)\t Streptococcus\t\t removed by filtration and sedimentation. \t\t(b)\t Myocardial infarction. Initially, floating debris is removed by sequential \t\t(c)\t Cyclosporin A\t\t filtration. Then the grit (soil and small pebbles) \t\t(d)\t Immunosuppressive agent are removed by sedimentation. Solids which settle \t 41.\t(a)\t Penicillium notatum (b) Acetic acid form the primary sludge and the supernatant \t\t(c)\t Fungus \t\t form the effluent. \t\t(d)\t Saccharomyces cerevisiae. \t49.\tIn aeration tank, bacteria and fungus grow by constant aeration due to vigorous agitation of water. \t 42.\t(a)\t Lactobacillus\t\t Bacteria and fungus form mesh-like structure called \t\t(b)\t Trichoderma polysporum flocs which consume major part of organic matter 218 Biology\u201312","present in the effluent. Once the BOD is reduced, \t \t \u2022\t Trichoderma producer cyclosporin-A. It acts effluent is taken to settling tank were flocs are as immunosuppressive agent allowed to settle. This sediment is called activated sludge. It is used as inoculum in aeration tanks. \t62.\tMethanogens are anaerobic bacteria which \t 50.\tBacteria and fungi. They consume major part of produce methane while digesting cellulose-rich organic matter present in effluent and reduces BOD. biowaste in anaerobic conditions. Methanogens \t51.\tFlocs consume major part of organic matter present in effluent and reduces BOD. digest organic matter and aerobic microbes of \t52.\tBacteria and fungus form mesh-like structure called flocs which consume major part of organic the sludge in the digester to produce a mixture matter present in the effluent and reduces BOD. \t53.\tMethanogens are anaerobic bacteria which of gases i.e. CCOH24 (methane), Hydrogen sulphide produce methane while digesting cellulose-rich (bHio2gSa)s.and which are collectively called biowaste in anaerobic conditions. \t54.\tRhizobium fixes atmospheric nitrogen only when \t63.\tBio-waste especially cow dung is collected and fed it is associated with the roots of legume plants. in inlet \u2192 the slurry is anaerobically digested in The bacteria obtain food and shelter from the digester due to action of methanogens \u2192 biogas plant and the plant gets fixed nitrogen in return. is produced and is collected in floating type gas \t55.\tMycorrhizae is a symbiotic association of a fungus holder \u2192 used slurry is removed from outlet and with the roots of higher plants. The fungus is used as manure in agricultural fields. absorbs phosphate from soil and passes it to the plant. It also provides resistance to the root-borne \t\t(a)\t Sludge outlet\t (b)\t Gas holder pathogen and increases tolerance of plant to salinity and drought. Genus of fungi-Glomus. \t\t(c)\t Dung and water \t 56.\t(a)\t Monascus purpureus \t64.\tOrganic farmers use living organisms i.e \t\t(b)\t Aspergillus niger biocontrol agents or biopesticides to control pests. \t\t(c)\t Penicillium notatum \t\t(d)\t Clostridium butylicum Two examples are: \t57.\tTrichoderma polysporum: it produces cyclosporin- \t\t(i)\t Bacillus thuringiensis can control cabbage A. looper (Trichoplusiani). \t\tAspergillus niger: it produces citric acid. \t\t(ii)\t Helicoverpazea (Cotton bollworm) is controlled \t 58.\t(a)\tBacteria, Fungi, Cyanobacteria, Anabaena, by the biocontrol agent Basulovirus helioths. Nostoc, Oscillatoria, Frankia (Any two) \t\t(b)\t Because leguminous plants have Rhizobium \t 65.\t(a)\t Used as bio control agents which are species- specific, narrow-spectrum insecticides with no in root nodules which is Nitrogen fixing bacteria. negative impacts on non target organisms. \t59.\tThe following steps help to improve quality of \t\t(b)\tUsed in bread making, brewing industry for water: ethanol and CO2 production. \t\t(c)\t Cholesterol lowering agent. \t\t\u2022\tFirst conventional Sedimentation, filtration and chlorination is done. \t\t(d)\t Produces Cyclosporin-A which is an immuno- suppressive agent. \t\t\u2022\tWater is then passed through six connected marshes seeded with algae, fungi and \t\t(e)\t Produces antibiotic penicillin. bacteria. \t\t(f)\tProduction of swiss cheese, characteristic \t\t\u2022\t These plants absorb pollutants and neutralize feature of which is large holes in cheese due water. to production of large amount of CO2. \t\t\u2022\t Thus Water is purified naturally. 66.\tMycorrhiza is symbiotic association between \t fungi and roots of higher plants. It helps to absorb 3 Marks Questions \t60.\tCyclosporin-A is produced by Trichoderma phosphorus from soil for the tree. polysporum. It is used as immuno-suppressor in \t \tAnabaena is free living cyanobacteria which fixes transplant patients. atmospheric nitrogen and adds organic matter to \t61.\tStreptococcus produces streptokinase. It acts as the soil clot buster \t \tRhizobium is symbiotic bacteria in leguminous \t \t \u2022\t Monascus produces statins. It acts as blood plants which fixes atmos-pheric nitrogen cholesterol lowering agent \t \tMethanobacterium digests cellulosic material and the used slurry is used as manure. \t \tTrichoderma is a fungus which acts as biocontrol agent for several plant pathogens. \t67.\tRefer answer no. 33. \t 68.\t(a)\t Bioactive molecule used to remove blood clot. \t\t(b)\t Trichoderma polysporum \t\t(c)\tImmuno-suppressant \t\t(d)\tStatin Microbes in Human Welfare \u2009219","(e)\t Blood cholesterol lowering agent water. Bacteria and fungus form mesh-like \t\t(f)\t Lactic acid structure called flocs which consume major \t 69.\t(a)\tThe fruit juices bought from market are part of organic matter present in the effluent. clearer as they are clarified by pectinases and \t\t(iii)\tOnce the BOD is reduced, effluent is taken to proteases enzymes. settling tank were flocs are allowed to settle. This sediment is called activated sludge. It is \t\t(b)\t Trichoderma polysporum: Cyclosporin-A used as inoculum in aeration tanks. Monascus purpureus: Statins \t\t(iv)\tRest of sludge is taken to anaerobic sludge \t70.\tSource and application of Cyclosporin A: digesters, anaerobic bacteria digest bacteria \t\tTrichoderma polysporum, used as immuno- and fungi and produce gases like hydrogen sulphide, carbon-di-oxide and methane suppressive agent in organ transplant patients. (collectively called as biogas). Biogas is inflammable and is used as source of energy. \t\tStreptokinase: Streptococcus, used as clot buster in patients with myocardial infarction. \t\t\t Treated water has reduced biological oxygen demand and is released in rivers and streams. \t\tStatins: Monascus purpureus, acts as blood cholesterol lowering agent. \t 77.\t(a)\tAfter flocs consume organic matter and the BOD of sewage or waste water is reduced \t71.\tRefer answer no. 66. significantly, the effluent is passed into a \t 72.\t(a)\tStatins settling tank where the bacterial flocs are \t\t(b)\t Blocks cholesterol lowering agent. settled. These sediments are called activated \t\t(c)\t Penicillium notatum sludge. \t\t(d)\tPenicillin \t\t(e)\t\tTrichoderma polysporium \t\t(b) Refer answer no. 49. \t\t(f)\tImmuno-suppressant \t 73.\t(a)\t Streptococcus: It produces strepto-kinase and \t78.\tActivated sludge is taken to anaerobic sludge digesters, anaerobic bacteria digest bacteria and is used as clot buster fungi and produce gases like hydrogen sulphide, carbon-di-oxide and methane (collectively called as \t\t (b)\t Lactobacillus: It produces lactic acid and is biogas). used to coagulate and partially digest milk protein to form curd. \t 79.\t(a)\tMethanogens are anaerobic bacteria which produce methane. \t\t(c)\t Saccharomyces cerevisiae: It produces ethanol, it is used to make bread, ferment \t\t(b)\tThey are present in gut of ruminants, and malted cereals and fruit juices. help in digestion of cellulose-rich diet of cattle. \t74.\tAntibiotics prevent multiplication of bacteria \t80.\tThe activated sludge is pumped into large tanks by interfering with bacterial metabolism of cell called anaerobic sludge digesters. The anaerobic wall formation in bacteria. The immune system bacteria digest the bacteria and the fungi in the of the host body then prevents further bacterial sludge. During this digestion, bacteria produce infection in body. Some antibiotics can be used a mixture of gases which form biogas. Biogas to treat a wide range of infections and are known constitute methane, hydrogen sulphide and as broad-spectrum antibiotics and some are carbon dioxide. used against few types of bacteria and are called narrow-spectrum antibiotics. \t81.\tBaculoviruses are species-specific, narrow- spectrum insecticides, Bacillus thuringiensis is \t75.\tAerobic and anaerobic bacteria, fungi are present used to kill lepidopteron larvae. Both of them in sewage water. After aeration, aerobic bacteria have no negative impact on non-target organisms. and fungi grow in large number and consume major part of organic matter present in effluent \t82.\tConventional use of chemical pesticides cause thus reduces BOD. Anaerobic bacteria grow in harm to non-target organisms and also cause sludge digesters where these digest the sludge environmental pollution which disturbs and form biogas. ecosystems. Biocontrol agents have no such negative impact on non-target organisms and \t 76.\t(i)\tPrimary treatment: Physical removal of environment. large and small particles is done by filtration and sedimentation. Settled down solid is \t\t(a)\t Bacillus thuringiensis kills caterpillars of insect called primary sludge and supernatant is larvae. called effluent. Effluent is then subjected to secondary treatment. \t\t(b)\t Nucleopolyhedrovirus acts as species-specific, narrow spectrum insecticide. \t\t(ii)\tSecondary treatment: Biological treatment happens here. \t 83.\t(a)\t Chemical fertilisers increase the soil pollution thus reducing its quality. Therefore, farmers \t\t\t In aeration tank, bacteria and fungus grow by use biofertilisers which enrich the quality of constant aeration due to vigorous agitation of the soil. 220 Biology\u201312","(b)\t Anabaena fixes atmospheric nitrogen, thus `` Increase resistance to root-borne pathogens enriching the nitrogen content of the soil. in plants In mycorrhiza, the fungal partner absorbs phosphorus from soil and passes it to the `` Increase plant tolerance to salinity and plant. drought \t84.\tInvolves biological organism such as aerobic and `` Overall increase in plant growth and anerobic microbes \/ bacteria and fungi to digest \/ development consume organic waste `` These microbes are preferred over chemical \t\tPrimary effluent is passed into aeration tank fertilizers because: where vigorous growth of aerobic microbes (flocs) take place, BOD reduced (microbes consume `` They do not pollute soil and water major part of organic matter), effluent is passed to settling tank where flocs sediment to produce `` They improve the soil texture and pH of the activated sludge, sludge is pumped to anerobic soil sludge digester to digest bacteria and fungi. \t\t(Refer Q. No. 83 (a) and 85 (a) chemical fertilizers) \t 85.\t(a)\t Use of chemicals to kill pests kill both useful \t 88.\t(a)\t Refer answer no. 76. organism and pest organisms, they are toxic \t\t(b)\tSewage water contains human excreta as for soil flora and humans and pollute soil & water. major component along with other organic matter like food particles. It also contains \t\t(b)\tBacteria\u2013Bacillus thuringiensis. pathogenic microbes and various toxins. So \t\t\t Fungus \u2013 Trichoderma it must be treated. \t\t\tInsect\u2013Ladybird beetle \t 89.\t(a)\tAerobic and anaerobic bacteria, fungi are 5 Marks Questions present in sewage water. After aeration, aerobic bacteria and fungi grow in large \t86.\tRefer answer no. 48 and 49.\t number and consume major part of organic \t87.\tBiofertilizers\u2013are the microbes which enrich the matter present in the effluent and thus reduce BOD. Anaerobic bacteria grow in sludge nutrient content of the soil. Role in agriculture: digesters where they digest the sludge and form biogas. `` Increase nutrient quantity in soil \t\t(b)\t Refer answer no. 72 secondary treatment. `` Fix atmospheric nitrogen Assertion & Reason Type Questions For question numbers 1\u20137: Two statements are \t\tReason: Lactic acid bacteria and rennet is used given-one labelled Assertion and the other labelled for the purpose. Reason. Select the correct answer to these questions from the code (a), (b), (c) and (d) as given below. \t 4.\tAssertion: In ripening of cheese, insoluble \t(a)\t Both assertion and reason are true and reason is proteins are cleaved to form soluble peptides. the correct explanation of assertion. \t\tReason: Hard cheese and soft cheese, both are ripened by lactic acid bacteria. \t(b)\tBoth assertion and reason are true but reason it not the correct explanation of assertion. \t 5.\tAssertion: Enzymes application in industry is enhanced by its immobilisation. \t(c)\tAssertion is true but reason is false. \t(d)\tBoth assertion and reason are false. \t\tReason: Immobilisation provides protection to \t 1.\tAssertion: Azotobacter fixes nitrogen in enzymes without affecting their activity. symbiotic form. \t 6.\tAssertion: Acetic acid is prepared by acetic acid bacteria. \t\tReason: Azotobacter form root nodules in the roots of leguminous plants. \t\tReason: Alcoholic fermentation and the conversion of alcohol to acetic acid are aerobic \t 2.\tAssertion: Rhizobium forms nodules on the roots processes. of legume plants. \t 7.\tAssertion: Aspergillus niger produces lactic acid. \t\tReason: Rhizobium fixes atmospheric nitrogen \t\tReason: Rhizopus produces citric acid. into organic forms which is used by the plant as nutrients. \t 1.\t(d)\t Answers 5.\t(a) \t 6.\t(c)\t \t 3.\tAssertion: Curdling is required in the 2.\t(b)\t 3.\t(b)\t 4.\t(c)\t manufacture of cheese. 7.\t(d) Microbes in Human Welfare \u2009221","Case Based Questions \t1.\t Read the following and answer any four question Biogas from (i) to (v) given below: P \t\tEnzymes are best known for their ability to Q catalise biochemical reactions without undergoing Fermentative microbes any change. A large number of enzymes are being used in biotechnological industry. Most Soluble compounds of them are obtained from microbes, Proteases degrade proteins and polypeptides. Most of the R commercially applicable proteases are alkaline and are biosynthesised mainly by bacteria such Proteins Fats Cellulose Hemicellulose as Pseudomonas, Bacillus and some fungi like, Aspergillus. These enzymes are used in clearing \t\tStudy the flow chart for biogas production given beer, softening of bread and meat, degumming here and answer the following question. of silk,etc. Alkaline serine proteases have the largest applications in bio-industry. Alkaline \t\t(i)\t Biogas is composed of mainly proteases have shown their capability to work under high pH, temperature and in presence of \t\t(a)\t Methane, CO2 inhibitory compounds. Another important group \t \t(b)\tH2S, H and O2 of enzymes is amylases. Amylolytic enzymes act \t\t(c)\tCO2, H2S and H on starch. These are obtained from Aspergillus, \t\t(d)\t Methane, CO2 and O2 Rhizopus and Bacillus sp. These are used in \t\t(ii)\t In this given flow chart, \u2018P\u2019 denotes clearing of turbidity in juices caused by starch, etc. \t\t(a)\t Cellulose degrading bacteria \t\t(b)\t Yeast and protozoa \t \t (i)\t Polypeptides are degraded by \t\t(c)\t Aerobic bacteria \t\t(a)\tAmylases\t (b)\tProteases \t\t(d)\t Methanogenic bacteria \t\t(c)\tPectinases\t (d)\tLipases \t\t(iii)\tWhat is represented by \u2018Q\u2019 in the flow chart? \t\t(ii)\t Amylolytic enzymes are not obtained from \t\t(a)\t Fat globules\t (b)\t Organic acids \t\t(a)\tAspergillus\t (b)\tRhizopus \t\t(c)\t Protein polymers\t (d)\tCarbohydrates \t\t(c)\tMucor\t (d)\tBacillus \t\t(iv)\t \u2018R\u2019 in the given flow chart causes \t\t(iii)\tClearing of turbidity in juices caused by starch \t\t(a)\t Fermentation of organic compounds is achieved by \t\t(b)\tAerobic breakdown of complex organic compounds \t\t(a)\tAmylases\t (b)\tProteases \t\t(c)\tAnaerobic digestion of complex organic \t\t(c)\tRennet\t (d)\t Both (a) and (b) compounds \t\t(iv)\t Select the incorrect option from the following. \t\t(d)\t Fermentation of monomers \t\t(a)\t Enzymes are proteinaceous substances. \t\t(v)\t If \u2018P\u2019 is not added in the procedure \t\t(b)\t Enzymes are substrate specific \t\t(a)\tCO2 will not be formed \t\t(b)\t methane will not be formed \t\t(c)\t Enzymes are large sized molecules \t\t(d)\tMicrobial enzymes can work only in \t\t(c)\tO2 will not be formed normal temperature and pH. \t\t(d)\t Organic compounds will not be converted \t\t(v)\tA farmer harvests corns and prepares corn to H2S starch. He wants to prepare some corn syrup \t 3.\tRead the following and answer any four from this. For the conversion he needs to use enzyme question from (i) to (v) given below: \t\tDisposal of untreated sewage into the river or \t\t(a)\tAmylase\t (b)\tGlucoamylases freshwater pond causes huge water pollution. \t\t(c)\tGlucoisomerases\t (d)\t All of these Four water samples from different sources (A, \t 2.\tRead the following and answer any four B, C, D) are collected and tested for BOD value question from(i) to (v) given below: \t\tVillagers in a place near Chambur started in a lab to assess their quality. The BOD values planning to make power supply for agricultural purposes from cow dung. They have started a are presented in the given table. Water samples biogas plant for the purpose. are collected from primary effluent, secondary effluent, untreated sewage and river water. Study the given table and answer the following. 222 Biology\u201312","Sample BOD (Mg\/L) \t\tStudy the diagram given here and answer the following questions. A 20 \t\t(i)\t In the diagram \u2018P\u2019 denotes B5 \t\t(a)\t aeration tank C 300 \t\t(b)\t primary settling tank D 400 \t\t(c)\t secondary settling tank \t\t(i)\t The source of sample \u2018C\u2019 is \t\t(d)\t sludge digester \t\t(a)\t Untreated sewage water \t\t(ii)\t Which of the following is incorrect regarding \t\t(b)\t River water the sludge released from P? \t\t(c)\t Primary effluent \t\t(a)\t It is formed after primary treatment. \t\t(d)\t Secondary effluent \t\t(b)\t It does not require aeration \t\t(ii)\tIf sewage in untreated condition is disposed \t\t(c)\t It possesses flocs of decomposer microbes off in a freshwater body then \t\t(d)\t It is used in landfills \t\t(a)\t BOD and dissolved oxygen both will decrease. \t\t(iii)\tA large number of aerobic heterotrophic microbes grow in \t\t(b)\t BOD and dissolved oxygen both will increase. \t\t(a)\tP\t (b)\tQ \t\t(c)\t BOD will increase and dissolved oxygen \t\t(c)\tR\t (d)\t both (a) and (b) will decrease. \t\t(iv)\t What is denoted by \u2018S\u2019 in the given diagram? \t\t(d)\t BOD will decrease and dissolved oxygen \t\t(a)\t Primary sludge will increase. \t\t(b)\t Primary effluent \t\t(iii)\tA large number of pathogenic microbes can be present in water sample of \t\t(c)\t Activated sludge \t\t(a)\tC\t (b)\tA \t\t(d)\t Secondary effluent \t\t(c)\t D\t (d)\t Both (a) and (c) \t\t(v)\t Assertion : The colloided and finely suspended matter of sewage form aggregates which are \t\t(iv)\t High value of BOD in sample D is due to called flocs. \t\t(a)\tHigh amount of inorganic wastes and \t\t\tReason : Flocs contain masses of bacteria, aerobic microbes. slime and fungal filaments. \t\t(b)\tHigh amount of organic wastes and \t\t(a)\tBoth assertion and reason are true and anaerobic microbes. reason is the correct explanation of assertion. \t\t(c)\tHigh amount of inorganic wastes and anaerobic microbes. \t\t(b)\tBoth assertion and reason are true but \t\t(d)\tHigh amount of organic wastes and reason is not the correct explanation of aerobic microbes. assertion. \t\t(v)\t River water is represented by the sample \t\t(c)\t Assertion is true but reason is false. \t\t(a)\tA\t (b)\t D \t\t(d)\t Both assertion and reason are false. \t\t(c)\tB\t (d)\tC A\t ns.\t 1.\t(i)\t(b)\t(ii)\t(c) \t 4.\tRead the following and answer any four \t\t\t(iii)\t(a)\t(iv)\t(d) question from (i) to (v) given below: \t\tGaura, a research student, get an assignment \t\t\t(v)\t(d) on sewage treatment plant (STP) to study the \t\t2.\t(i)\t(a)\t(ii)\t(d) microbial load. After visiting such plant in his \t\t\t(iii)\t(b)\t(iv)\t(c) locality, he makes a simplified diagram of the \t\t\t(v)\t(b) STP for his project. \t\t3.\t(i)\t(c)\t(ii)\t(c) \t\t\t(iii)\t(d)\t(iv)\t(d) \t\t\t(v)\t(c) \t\t4.\t(i)\t(b)\t(ii)\t(c) \t\t\t(iii)\t(b)\t(iv)\t(c) \t\t\t(v)\t(b) qqq Microbes in Human Welfare \u2009223","9 Biotechnology: Principles and Processes Topics Covered \t9.1\t Principles of Biotechnology \t9.2\t Tools of Recombinant DNA Technology 9\t .3\t Process of Recombinant DNA Technology C hapter map BIOTECHNOLOGY : PRINCIPLES & PROCESSES Principles of Genetic Tools of rDNA Process of rDNA Process of rDNA Downstream Engineering technology technology technology processing rDNA Gene cloning Gene transfer \u2022 Separation \u2022 Purification \u2022 Formulated with preservatives \u2022 Clinical trials \u2022 Quality control Restriction Cloning vectors Competent enzyme host Isolation of Cutting of DNA by Amplification & Transfer of rDNA \u2022 \u0007Obtaining the Foreign rDNA restriction enzyme insertion of rDNA into host cell Gene Product into host cell \u2022 Recombinant protein \u2022 Bioreactors As stated by 'European Federation of Biotechnology' (EFB), biotechnology is defined as \u2018the integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services\u2019. Topic 1. Principles of Biotechnology \u2022\t Essential techniques for biotechnology are: \u2022\t The advantages of biotechnological application over traditional hybridization are: \u0017\u0017Genetic engineering: The DNA and RNA are changed and introduced into the host organisms. \u0017\u0017Only desirable genes are multiplied. This changes the phenotype of host organisms. \u0017\u0017Results are obtained in less time as no normal \u0017\u0017Maintenance of sterile condition: The sexual reproductive cycle is required. working conditions should be free of microbial contamination so that only desired microbe or \u2022\t When foreign gene is inserted in host DNA, eukaryotic cell can be cultured in large quantities. the resultant gene is called recombinant DNA. Formation of recombinant DNA requires two 224","processes which allow us to insert only desirable The cut piece of DNA is then linked to plasmid DNA. gene in target organism. Plasmid acts as vector for foreign DNA. \u0017\u0017Gene cloning: Many copies of desired genes are \u2022\t Joining of two DNA is done with an enzyme called formed. DNA sequence in which the gene is to be DNA ligase. inserted should have origin of replication. It is a specific DNA sequence which is responsible for \u2022\t Then this plasmid was inserted into Escherichia initiating replication. The foreign DNA is linked coli where it multiplied and formed multiple copies with this Ori, and desired DNA gets copied along of desired gene. with host DNA while undergoing replication. \u2022\t Thus there are three basic steps in modifying an \u0017\u0017Gene transfer: Inserting desired gene into the organism genetically: genome of host. First artificial recombinant DNA was constructed by Stanley Cohen and Herbert \u0017\u0017Identification of desired gene Boyer in 1972. They linked antibiotic resistance gene in the plasmid of Salmonella typhimurium. \u0017\u0017Introduction of identified DNA into host \u2022\t Cutting of a piece of DNA at specific location is done \u0017\u0017Maintenance of the recombinant DNA in host and in its progeny. by special enzymes called restriction enzymes. Topic 2. Tools of Recombinant DNA Technology \u2022\t There are three main tools to make recombinant DNA \u0017\u0017Restriction endonucleases and ligase enzyme \u0017\u0017Cloning vectors \u0017\u0017Competent host for transformation Restriction Endonucleases \u2022\t Restriction enzymes were discovered in 1963 in E. coli which inhibited the growth of bacteriophage in the bacterial cell. \u2022\t First restriction enzyme isolated was Hind II. It always cuts the DNA molecule at specific location with specific base pairs. This specific sequence at which a restriction enzymes cuts DNA is called recognition sequence. Convention for Naming a Restriction Endonuclease (RE) \u2022\t First letter of the name comes from the name of genus \u2022\t Second two letters come from specific epithet. \u2022\t The fourth capital letter comes from strain of the bacteria \u2022\t Roman numbers come from the order in which the enzymes were isolated from the bacteria. Example: In EcoRI, where, \u0017\u0017E: Escherichia \u0017\u0017co: coli \u0017\u0017R: RY strain \u0017\u0017I: order of the isolation of enzyme Functioning of RE \u2022\t RE inspects the length of DNA \u2022\t When specific palindromic sequence is located by RE, it binds to DNA and cuts both the strands of DNA by breaking sugar phosphate backbone, little away from the centre but between the same base sequence. This produces sticky ends. This facilitates the joining of two DNA molecules, one desired and the other vector DNA which is cut with the same RE, by DNA ligase. The resultant DNA is recombinant DNA which is then inserted into desired host like E. coli. When this bacteria divides, the inserted DNA also divides along with the bacteria. \u2022\t Specific sequences are palindromic nucleotide sequences that read same both forward and backward. \u2022\t e.g. For EcoRI, specific palindromic sequence is Biotechnology: Principles and Processes \u2009225","DIRECTION OF READING 5'\u2013GAATTC\u20133' 3'\u2013CTTAAG\u20135' DIRECTION OF READING Cutting by EcoRI 5'\u2013GAATTC\u20133' 3'\u2013CTTAAG\u20135' The enzyme cuts both DNA Cutting by EcoRI strands at the same site Eco RI cuts the DNA between bases G and A Vector DNA only when the sequence GAATTC is present in the DNA Foreign DNA GAA TTC G AA T TC CT T AAG C T TAAG EcoRI Sticky end G AAT T C CT TA A G Sticky end DNA fragments join at sticky ends Recombinant DNA Foreign DNA Vector DNA (Plasmid) Same restriction enzyme cutting both foreign DNA and vector DNA at specific point Ligases join foreign DNA to plasmid E.coli Transformation Cells divide 226 Biology\u201312","Separation and Isolation of DNA Fragments A cloning vectors must have following features: \u2022\t When the DNA is cut by RE (Restriction Enzyme), \u0017\u0017Origin of replication (ori): It is a sequence many fragments of DNA are formed. These where replication starts. When any alien DNA fragments can be separated by a technique called is inserted along with origin of replication, it as gel electrophoresis. The DNA fragments replicates along with plasmid. Ori also controls are separated on the basis of their size. The solid copy number so a plasmid with high copy number medium in which the fragments of DNA separate should be chosen. out is agarose gel. Agarose is extracted from a sea weed. The agarose gel acts as a sieve and separates \u0017\u0017Selectable marker: It helps in identifying the fragments of DNA according to their sizes. and eliminating non-transformants and allows the growth of transformants. Commonly used \u2022\t Fragments of DNA are formed when it is subjected selectable markers in E. coli are ampicillin to restriction endonuclease digestion. resistance genes, chloramphenicol resistance genes, tetracyclin or kanamycin resistance genes. \u2022\t DNA is negatively-charged molecule. When electric field is applied, DNA moves towards positively- \u0017\u0017Cloning sites: It is a site or sequence on vector charged anode through agarose gel matrix. Agarose DNA which is recognized by a restriction enzyme is a natural polymer extracted from a sea weed. and is used to link alien DNA. Presence of many When polymerized, agarose forms gel and acts as recognition sites within the cloning vector will a sieve which separates DNA according to the size complicate the gene cloning. of fragments. Small fragment will move faster than the larger fragment. EcoR I Cla I Hind III \u2022\t DNA is visualized by staining it with Ethidium Pvu I BamH I bromide (EtBr), otherwise it is not visible to naked Pst I amp* tet* eyes. pBR322 Sal I \u2022\t Bright orange bands of DNA are visible under UV light. ori Wells DNA bands Pvu II Largest Smallest \u2022\t E.coli cloning vector pBR322 showing restriction sites (Hind III, EcoR I, BamH I, Sal I. Pvu II, Pst 123 4 I, Cla I) \u2022\t Desired fragment is cut and purified from agarose \u2022\t ori and antibiotic resistance genes (ampR and tetR). gel. This is called DNA elution. The extracted DNA is then subjected to the formation of recombinant \u2022\t Rop codes for the proteins involved in the replication DNA. of the plasmid. Cloning Vectors \u2022\t Plasmids and bacteriophages can replicate within \u2022\t The foreign DNA is linked to plasmid within one of the antibiotic resistant genes. a bacterial cell independent of genomic DNA. Bacteriophage can replicate itself in large number \u2022\t For example, in the given figure of pBR322, the of copies i.e. its copy number is very high. foreign DNA can be inserted within tetracycline resistant gene by using BamHI as restriction \u2022\t Similarly, some plasmids also have high copy enzyme for both desired DNA and plasmid DNA. number. The recombinant plasmid will lose the tetracycline resistance capacity due to insertion of foreign DNA \u2022\t If we ligate foreign DNA with plasmid, it will also and can be recognized as transformants from non- replicate along with plasmid. transformants by plating the transformants on ampicillin containing medium. First the bacteria- containing plasmid is cultured on ampicillin- containing medium. Then they are transferred to tetracycline containing medium. Recombinants will not grow on tetracycline- medium due to the fact Biotechnology: Principles and Processes \u2009227","that the tetracycline gene gets inactivated due to but cannot cause tumour. Retroviruses are also insertion of alien DNA. This will help us to identify genetically engineered so that tumour-causing genes transformants. are removed. \u2022\t The above process is cumbersome as it requires Competent Host for Transformation with simultaneous plating on two plates with different Recombinant DNA antibiotics. \u2022\t DNA being hydrophilic cannot pass through cell \u2022\t Alternative selectable marker is the gene which membranes, so bacteria\u2019s cell membrane is modified produces enzyme b-galactosidase. This produces blue so that it can take DNA easily. Such bacterial cells colour in the presence of chromogenic substance. are called competent cells. The insertion of alien DNA within the gene of b-galactosidase will inactivate it and does not \u2022\t They are made competent by treating them with produce colour. Such colonies which does not produce divalent cations such as Ca2+. This creates pores in colour are transformats. cell wall so that DNA can enter. Then the cells are incubated on ice followed by heat shock in which Vectors for Cloning genes in Plants and Animals brief exposure to 42oC is given. This enables bacteria to take up recombinant DNA. \u2022\t Agrobacterium tumifaciens, a soil bacteria and tumour causing retroviruses are used to insert the \u2022\t Another way is injecting DNA directly into nucleus desired gene in plants and animals, respectively. of animal cells with the help of micro-injection. Normally A. tumifaciens causes tumour by transferring Ti plasmid, a tumour-causing gene \u2022\t A biolistic or gene gun is also used in plants where in plants. Ti plasmid is disarmed by modifying it gold or tungsten particles are coated with DNA and in such a way that it can transfer desirable gene then are bombarded into cell. \u2022\t Use of a disarmed pathogen is another method by which recombinant DNA is transferred into host. Topic 3. Process of Recombinant DNA Technology This is Carried Out in Following Steps: Isolation of genetic material (DNA) \u2022\t Purified DNA is isolated by treating bacterial or plant or animal cells with following enzymes to degrade cell wall and or cell membrane and other components. \u0017\u0017Lysozyme for bacterial cell wall \u0017\u0017Cellulase for plant cell wall \u0017\u0017Chitinase for fungal cell wall. \u0017\u0017To degrade proteins such as histones: Protease \u0017\u0017To degrade RNA : Ribonuclease \u2022\t Then pure DNA is precipitated by adding chilled ethanol. Cutting of DNA at Specific Locations \u2022\t Both foreign and vector DNA is incubated with restriction enzymes under optimal conditions and then gel electrophoresis is done to check the progression of digestion. \u2022\t Then desired DNA is joined with vector DNA with enzyme ligase. This results into recombinant DNA. Amplification of Gene of Interest using Polymerase Chain Reaction (PCR) \u2022\t Multiple copies of gene of interest are synthesized in vitro. \u2022\t DNA template and two sets of primers, which are small, chemically synthesized oligonucleotides that are complementary to the regions of DNA, Taq polymerase enzyme, (dNTPs) are used which make multiple copies in three steps. \u0017\u0017Denaturation: Two strands of DNA separates by heating DNA. \u0017\u0017Annealing: primers attach at complementary positions on DNA. \u0017\u0017Extension: Taq DNA polymerase adds deoxynucleotides and a new strand of DNA is synthesized. 228 Biology\u201312","Region to be amplified 5' 3' dsDNA (a) Denaturation 3' 5' 5' Heat 5' 3' 3' 3' 5' 5' Primers (b) Annealing of primers 3' 5' 3' 5' DNA polymerase 3' (Taq polymerase + deoxynucleotides) 3' (c) Extension of primers 5' 3' 5' 30 cycles Amplified (~1 billion times) Polymerase Chain Reaction (PCR): Each cycle has three steps: (a) Denaturation, (b) Primer annealing and (c) Extension of primers. \u2022\t The steps are repeated upto 30 cycles and ~1 billion is then purified by using different separation copies are produced. techniques. \u2022\t Taq polymerase is thermo-stable DNA polymerase \u2022\t Large volume up to 100-1000 litres is cultured in isolated from bacterium Thermus aquaticus which large vessels called bioreactor. The bioreactors are remain active during high temperature-induced continuously fed with fresh medium containing denaturation of double stranded DNA. materials like substrate, salts, vitamins. Oxygen supply and other optimum growth conditions \u2022\t The amplified fragment of DNA obtained from PCR like temperature and pH, are maintained in the can then be ligated to a vector for further cloning. bioreactor. Insertion of Recombinant DNA into the Host cell\/ \u2022\t Common types of bioreactors are stirred tank organism bioreactors and sparged stirred bioreactor. \u2022\t Vector carrying foreign DNA is then inserted \u2022\t Optimum conditions within a bioreactor are into recipient cell by making it competent. The maintained by an agitator system, an oxygen delivery transformants are then selected using selectable system, a foam control system, a temperature control marker like ampicillin-resistance gene or gene of system, pH control system and sampling ports b-galactosidase enzyme. so that small volume of the culture is withdrawn periodically. Obtaining Foreign Gene Product \u2022\t The transformed cells are cultured in large scale to \u2022\t Stirred tank is cylindrical with curved base which facilitates the mixing of reactor contents. Stirrer express foreign protein called recombinant protein evenly mixes oxygen in culture. under optimum conditions. The desired protein \u2022\t In sparged bioreactor, air is bubbled through culture which increases oxygen transfer area. Increased surface Acid\/Base Motor area for oxygen for pH control Foam braker transfer Gas entrainment Steam for Flat bladed sterlisation impeller Culture broth Bubbles dramatically increase the oxygen Sterile Air transfer area (a) Simple stirred-tank bioreactor, (b) Sparged stirred-tank bioreactor through which sterile air bubbles are sparged Biotechnology: Principles and Processes \u2009229","Downstream Processing: \u2022\t It includes separation and purification under strict quality control testing system. \u2022\t The product is then added with suitable preservatives, undergoes clinical trials in case of drugs, and then marketed. EXERCISE I. Multiple Choice Questions \t8.\tWhich of the following has popularised the PCR (polymerase chain reactions)? \t1.\tAn enzyme catalysing the removal of nucleotides from the ends of DNA is: \t\t(a)\t Easy availability of DNA template \t\t(a)\tendonuclease\t (b)\texonuclease \t\t(b)\t Availability of synthetic primers \t\t(c)\t DNA ligase\t (d)\t Hind \u2013 II \t\t(c)\t Availability of cheap deoxyribonucleotides \t2.\tThe transfer of genetic material from one \t\t(d)\t Availability of \u2018Thermostable\u2019 DNA polymerase bacterium to another through the mediation of \t9.\tSignificance of 'heat shock' method in bacterial a vector like virus is termed as: transformation is to facilitate: \t\t(a)\tTransduction\t (b)\tConjugation \t\t(a)\t Binding of DNA to the cell wall \t\t(c)\tTransformation\t (d)\tTranslation \t\t(b)\t Uptake of DNA through membrane transport proteins \t3.\tWhich of the given statement is correct in the context of observing DNA separated by agarose \t\t(c)\tUptake of DNA through transient pores in the bacterial cell wall gel electrophoresis? \t\t(d)\t Expression of antibiotic resistance gene \t\t(a)\t DNA can be seen in visible light \t10.\tThe role of DNA ligase in the construction of a \t\t(b)\tDNA can be seen without staining in visible recombinant DNA molecule is: light \t\t(a)\tFormation of phosphodiester bond between \t\t(c)\tEthidium bromide stained DNA can be seen two DNA fragments in visible light \t\t(b)\t Formation of hydrogen bonds between sticky \t\t(d)\tEthidium bromide stained DNA can be seen ends of DNA fragments under exposure to UV light \t\t(c)\t Ligation of all purine and pyrimidine bases \t4.\t'Restriction' in Restriction enzyme refers to: \t\t(d)\t None of the above \t\t(a)\tCleaving of phosphodiester bond in DNA by the enzyme II. Fill in the blanks \t\t(b)\t Cutting of DNA at specific position only \t1.\tTi plasmid is found in ______ . \t2.\tThe protein coat of virus is called _____ . \t\t(c)\tPrevention of the multiplication of bacterio- \t3.\tPhages infect the _____ cells. phage in bacteria \t4.\tViruses are _____ obligate parasites. \t\t(d)\t All of the above III. True or False \t5.\tWhich of the following is not required in the \t1.\tMicroinjection is used to ligate DNA fragments. preparation of a recombinant DNA molecules? \t2.\tGene gun is used to inject DNA into host cells. \t3.\tChitinase are used to dissolve cell wall of fungus. \t\t(a)\t Restriction endonuclease (RE) \t4.\tChloramphenicol is used as a marker in selecting \t\t(b)\t DNA ligase transformats in genetic engineering. \t\t(c)\t DNA fragments \t5.\tPlasmids are present in single number in a bacterial cell. \t\t(d)\t E.coli \t6.\tEthidium bromide is a staining agent in \t6.\tIn agarose gel electrophoresis, DNA molecules electrophoresis. are separated on the basis of their: \t7.\tEndonucleases made a cut at the end of the DNA \t\t(a)\t Charge only strand. \t\t(b)\t Size only \t8.\tThe origin of replication is responsible for initiating replication of the chromosome. \t\t(c)\t Charge to size ratio \t\t(d)\t All of the above \t7.\tThe most important feature in a plasmid to be used as a vector is: \t\t(a)\t Origin of replication (ori) \t\t(b)\t Presence of a selectable marker \t\t(c)\t Presence of sites for restriction endonuclease \t\t(d)\t Its size 230 Biology\u201312","IV.\tMatch the items in Column I with those \t 15.\tName the specific sequence of DNA in a plasmid of Column II: that the 'gene of interest' ligates with, to enable it Column I Column II to replicate.\b [All India 2013 C] \t (A)\tTi-plasmid \t(i)\tComponent \t 16.\tState the role of DNA ligase in bio-technology. of bacterial chromosome \b [Delhi 2012] \t 17.\tMention the use of cloning vector in bio- technology.\b[Delhi 2011] \t (B)\tBacteriophages \t(ii)\tAgrobacterium \t 18.\tWhy is it essential to have a selectable marker \t (C)\tSingle circular \t(iii)\tProtein coat of in a cloning vector?\b [All India 2011] DNA molecule viruses \t 19.\tWhy do DNA fragments move towards the anode \t (D)\tCapsid \t(iv)\t Viruses, infecting during gel-electrophoresis?\b [Delhi 2011 C] bacteria \t 20.\tIn the year 1963, two enzymes responsible for restricting the growth of bacteriophage in E. coli 1 Mark Questions were isolated. How did the enzymes act to restrict \t 1.\tBiotechnologists refer to Agrobacterium the growth of the bacteriophage? tumifaciens as a natural genetic engineer of plants. Give reasons to support the statement. \b [All India 2011 C] \b[All India 2011] \t 21.\tHow is the action of exonuclease different from that of endonuclease?\b [All India 2010] OR \t 22.\tMention the role of molecular scissors in \t\tWhy is Agrobacterium tumefaciens a good cloning recombinant DNA technology.\b [All India 2010] vector?\b[All India 2008] \t 23.\tName the technique used for separating DNA \t2.\tSuggest a technique to a researcher who needs fragments in the laboratory.\b [Delhi 2008] to separate fragments of DNA.\b [Delhi 2016] \t 24.\tWhat is the role of ethidium bromide during \t3.\tList the key tools used in recombinant DNA agarose-gel electrophoresis of DNA fragments?\t technology.\b[Delhi 2011] \b[AIl India 2008 C] \t4.\tWhat is EcoRI? How does EcoRI differ from an exonuclease? \b [Delhi 2015 C] \t25.\tWrite the importance of the bacterium Thermus aquaticus in polymerase chain reaction. \t 5.\tHow can bacterial DNA be released from the bacterial cell for biotechnology experiments? \b [Delhi 2013 C] \b [Delhi 2011] \t 26.\tMention the source of thermostable DNA polymerase.\b[All India 2013 C] \t 6.\tWrite the two components of the first artificial recombinant DNA molecule constructed by Cohen \t 27.\tWhy is it not possible for an alien DNA to become part of a chromosome anywhere along its length and Boyer. \b [Foreign 2014] and replicate normally?\b [All India 2008] \t 7.\tMention the type of host cells suitable for the gene guns to introduce in alien DNA. \t 28.\tWhat is the host called that produces a foreign gene product? What is this product called?\t \b [Delhi 2014] \b[Foreign 2010] \t8.\tName the host cells in which microinjection technique is used to introduce an alien DNA. \t 29.\tWhy is the enzyme cellulase used for isolating genetic material from plant cells but not for \b [Foreign 2014] animal cells?\b [Delhi 2010] \t 9.\tName the material used as matrix in gel electro- phoresis and mention its role.\b[All India 2014 C] \t 30.\tWhat is a plasmid?\b [Delhi 2008] \t10.\tState what happens when an alien gene is ligated \t31.\tWhat are Cry genes? In which organism are they present?\b[All India 2017] at salI site of pBR322 plasmid.\b [Delhi 2013 C] \t 11.\tHow is Agrobacterium tumifaciens able to 2 Marks Questions transform a normal plant cell into a tumor? \t32.\tDiscuss the role the enzyme DNA ligase plays \b [Delhi 2013 C] during DNA replication. \b [Delhi 2016] \t 12.\tHow can retroviruses be used efficiently in bio- \t 33.\tName the source organism that possesses Taq technology experiments inspite of them being polymerase. What is so special about the function disease causing?\b [All India 2013 C] of this enzyme?\b [All India 2012] \t 13.\tState what happens when an alien gene is ligated at PvuI site of PBR322 plasmid. OR \b [All India 2013 C] \t\tWhy is Taq polymerase preferred in PCR? Mention the source of this enzyme. \t 14.\tWhy is 'Plasmid' an important tool in bio- technology experiments?\b [AI 2013 C] \b [Delhi 2015 C] Biotechnology: Principles and Processes \u2009231","OR \t 41.\tHow does a restriction nuclease function? Explain.\b[All India 2014] \t\tExplain the contribution of Thermus aquaticus in the amplification of a gene of interest. \t 42.\tHow is insertional inactivation of an enzyme used as a selectable marker to differentiate \b [Delhi 2009] recombinants from non-recombinants? \t34.\tName the type of bioreactor shown. Write the purpose \b [Foreign 2014] for which it is used. \b [All India 2011] \t 43.\tExplain palindromic nucleotide sequence with the help of a suitable example.\b [Foreign 2014] \t 44.\tWhy is making cells competent essential for biotechnology experiments? List any two ways by which this can be achieved.\b[All India 2014 C] \t 45.\t(a)\t Mention the difference in the mode of action of exonuclease and endonuclease. \t\t(b)\t How does restriction endonuclease function? \b[Delhi 2013] \t35.\tExplain the work carried out by Cohen and Boyer \t 46.\t(a)\tExplain how to find whether an E. Coli that contributed immensely in biotechnology. bacterium has transformed or not when \b[Delhi 2012] a recombinant DNA bearing ampicillin- resistant gene is transferred into it. \t36.\t\tA schematic representation of Polymerase \t \tChain Reaction (PCR) up to the extension \t\t(b)\tWhat does the ampicillin-resistant gene act \t\tstage is given below. Answer the questions that as in the above case?\b [Delhi 2013] follow. \t 47.\tWhy and how bacteria can be made 'competent'? \b[Delhi 2013] 5' 3' A \t 48.\tWrite any four ways used to introduce a desired 3' 5' DNA segment into a bacterial cell in recombinant 5' Heat technology experiments.\b [Delhi 2013] 5' 3' 3' \t 49.\tHow is the bacterial cell made competent to 3' 3' 5' receive recombinant DNA? Explain.\b[Delhi 2013] B \t50.\t(a)\t How is an exonuclease functionally different from an endonuclease? 5' \t\t(b)\tGive an example of any two endonucleases other than SalI.\b [Delhi 2013] C+ deoxynucleotides \t 51.\tState the role of UV-light and ethidium bromide 5' 3' during gel electrophoresis of DNA fragments. 3' 5' \b [Delhi 2012 C] 5' 3' \t 52.\tExplain the role of Ti plasmids in bio-technology. 3' 5' \b[Delhi 2011] \t \t 53.\tHow are recombinant vectors created? Why is only one type of restriction endonuclease required \t\t(i)\t Name the process A. for creating one recombinant vector? \t\t(ii)\t Identify B. \b [Foreign 2011] \t\t(iii)\tIdentify C and mention its importance in PCR. \t 54.\t A recombinant DNA is formed when sticky ends \b[Foreign 2010] of vector DNA and foreign DNA join. Explain how the sticky ends are formed and get joined. \t37.\tAny recombinant DNA with a desired gene is required in billion copies for commercial use. How \b[All India 2010] is the amplification done? Explain. [Delhi 2010 C] \t 55.\t(a)\tIllustrate the recognition sequence of EcoRI \t 38.\tState how has Agrobacterium tumifaciens been and mention what such sequences are called? made a useful cloning vector to transfer DNA to plant cells.\b [Delhi 2014] \t\t(b)\tHow does restriction endonuclease act on a DNA molecule?\b [All India 2010 C] \t 39.\tHow are sticky ends' formed on a DNA strand? Why are they so called?\b [Delhi 2014] \t 56.\tA and B are the two different cloning vectors in two different bacterial colonies cultured in \t 40.\tWrite the role of ori and restriction site in a cloning vector pBR322.\b [Delhi 2014] chromogenic substrate. Bacterial colonies with coloning vector A were colourless whereas 232 Biology\u201312","those with B were blue coloured. Explain giving \t71.\tWhat are cloning sites in a cloning vector? reasons the cause of the difference in colour that Explain their role. Name any two such sites in pBR322.\b[All India 2014 C] appeared.\b[All India 2010 C] \t 57.\tHow is DNA isolated in purified form from a \t72.\tHow are the DNA fragments separated and bacterial cell?\b [All India 2008 C, 2009] isolated for DNA fingerprinting? Explain. \t 58.\tName the source organism from which Ti plasmid \b [Foreign 2012 C] is isolated. Explain the use of this plasmid in biotechnology.\b[Foreign 2009] \t73.\tHow are the following used in biotechnology? \t 59.\tName the natural source of agarose.Mention one \t\t(a)\t Plasmid DNA role of agarose in bio-technology.\b[Delhi 2009 C] \t\t(b)\t Recognition sequence \t\t(c)\t Gel electrophoresis\b [All India 2011 C] \t 60.\t (A) DNA AATTC \t 74.\tHow is the amplification of a gene sample of interest carried out using Polymerase Chain GG C T T AA (B) DNA Reaction (PCR)? \b [All India 2012] \t\tStudy the linking of DNA fragments shown OR above. \t \tExplain in sequence the process of amplification \t\t(a)\t Name 'A' DNA and 'B' DNA. of a gene of interest using polymerase chain \t\t(b)\t Name the restriction enzyme that recognises reaction.\b [All India 2012, 2012 C, 2013 C] this palindrome. OR \t\t(c)\tName the enzyme that can link these two DNA fragments.\b [Delhi 2008] \t \tHow is repeated amplification of DNA made possible during PCR? \b [All India 2008 C] \t 61.\tHow do 'ori' and 'cloning sites' facilitate cloning into a vector?\b [All India 2008 C] \t 75.\t(a)\tIdentify (A) and (B) illustrations in the following: \t 62.\tName two commonly used bioreactors. State the importance of using a bioreactor.\b [Delhi 2013] \t\t(i)\t A \t 63.\tName the source of the DNA polymerase used in 5' \u2013 G \u2013 3' PCR technique. Mention why it is used. 3' \u2013 C T T A A G \u2013 5' [All India 2013] \t\t(ii)\t C \t 64.\t(a)\tMention the number of primers required in each cycle of polymerase chain reaction Plasmid (PCR). Write the role of primers and DNA polymerase in PCR. \t\t Replication \t\t(b)\tGive the characteristic feature and source B organism of the DNA polymerase in PCR. \t\t(b)\t Write the term given to (A) and (C) and why? \b[All India 2011] \t\t(c)\t Expand PCR. Mention its importance in bio- \t 65.\tWhat is genetic engineering? List the steps in technology.\b[Delhi 2011] DNA technology.\b [All India 2011] \t76.\tPrepare a flow chart in formation of recombinant \t 66.\tName the organism from where the thermostable DNA by the action of restriction endonuclease DNA polymerase is isolated. State its role in enzyme EcoRI. \b [Foreign 2015 C] genetic engineering.\b [Foreign 2011] OR \t 67.\tExplain with the help of a suitable example the naming of a restriction endonuclease. \t\tHow does a restriction endonuclease function? Name a restriction endonuclease and write the \b [Delhi 2014] specific sequence of bases that it recognizes. \t 68.\tExplain the action of the restriction endonuclease \t77.\tHow can DNA segments, separated by gel EcoRI.\b[Foreign 2010] electrophoresis, be visualised and isolated? \t 69.\tHow are the DNA fragments separated by gel \b [All India 2008] electrophoresis visualised and separated for use in constructing recombinant DNA? \t78.\t(a)\tWhy must a cell be made \u2018competent\u2019 in biotechnology experiments? How does calcium \b [Foreign 2010] ion help in doing so ? 3 Marks Questions \t\t(b)\tState the role of \u2018biolistic gun\u2019 in bio- technology experiments.\b [All India 2016] \t70.\t Name and explain the technique used for separating DNA fragments and making them \t79.\t(a)\tName the selectable markers in the cloning available for biotechnology experiments. vector pBR322? Mention the role they play. \b[All India 2014, Foreign 2015] Biotechnology: Principles and Processes \u2009233","(b)\tWhy is the coding sequence of an enzyme \t83.\tDraw a schematic sketch of pBR 322 plasmid and (b-galactosidase) a preferred selectable label the following in it: marker in comparison to the ones named \t\t(a)\t Any two restriction sites. above? \b [All India 2016] \t\t(b)\t Ori and rop genes. \t\t(c)\t An antibiotic resistant gene. \b [Delhi 2012] OR \t 84.\tMany copies of a specific gene of interest are \t\tWhy does the \u2018insertional inactivation\u2019 method required to study the detailed sequencing of bases to detect recombinant DNA is preferred to in it. Name and explain the process that can help \u2018antibiotic resistance\u2019 procedure? \b[Foreign 2016] in developing large number of copies of this gene of interest. \b[Foreign 2015 C] \t80.\tExplain the role of the enzyme EcoRI in recombinant DNA technology. \b [Foreign 2016] OR OR \t\tExplain with the help of an example the \t\tSuggest and describe a technique to obtain relationship between restriction endonuclease multiple copies of a gene of interest in vitro. and a palindromic nucleotide sequence. \b [Delhi 2016] \b [Foreign 2016] \t85.\tDraw a labelled sketch of sparged-stirred- \t\ttank bioreactor. Write its application. \t81.\tRearrange the following in the correct sequence \b [Delhi 2015] to accomplish an important biotechnological \t 86.\tState the functions of the following in the cloning reaction: \b vector pBR322: \t\t(a)\t In vitro synthesis of copies of DNA of interest \t\t(b)\t Chemically synthesized oligonucleotides \t\t(c)\t Enzyme DNA-polymerase \t\t(a) Ori \u2003 (b) rop, and (c) HindIII sites \t\t(d)\t Complementary region of DNA \b[All India 2015 C] \t\t(e)\t Genomic DNA template \t 87.\tD\t raw pBR322 cloning vector, Label 'ori', 'rop' and \t\t(f)\t Nucleotides provided any one antibiotic resistance site on it and state \t\t(g)\tPrimers their functions.\b [All India 2015 C] \t\t(h)\tThermostable DNA-polymerase (from \t 88.\tDraw a schematic diagram of the E. coli cloning Thermus aquaticus)\b [All India 2015] vector pBR322 and mark the following in it: \t82.\t b ClaI c \t\t(a)\t ori PvuI \t\t(b)\t rop PstI a BamHI \t\t(c)\t ampicillin resistance gene d \t\t(d)\t tetracycline resistance gene pBR322 SalI \t\t(e)\t restriction site BamHI \t\t(f)\t restriction site EcoRI\b [AIl India 2014 C] ori \t 89.\t(a)\tDraw schematic diagrams of segments of a rop vector and a foreign DNA with the sequence of nucleotides recognised by EcoRI. Pvu II \t\t(b)\tDraw the vector DNA segment and foreign DNA segments after the action of EcoRI and \t \t(a)\t Identify the selectable markers in the diagram of E. coli vector shown above. label the sticky end produced. \t\t(b)\t How is the coding sequence of b\u2013 galactosidase \b[AlI India 2014 C] considered a better marker than the ones \t 90.\t(a)\tE x p l a i n t h e b a s i s o n w h i c h t h e g e l identified by you in the diagram? Explain. electrophoresis technique works. \b[Delhi 2009] OR \t\t(b)\tWrite any two ways the products obtained through this technique can be utilised. \t\t(a)\t A recombinant vector with a gene of interest inserted within the gene of b-galactosidase \b[Delhi 2013 C] enzyme, is introduced into a bacterium. Explain the method that would help in \t91.\tExplain the importance of \u2013 selection of recombinant colonies from non- \t\t(a)\t Restriction Endonuclease, recombinant ones. \t\t(b)\t \\\"Ori\\\" and \t\t(b)\t Why is this method of selection referred to as \u201cinsertional inactivation\u201d?\t\b [All India 2012] \t\t(c)\t gel-electrophoresis in recombinant DNA technology.\b[Delhi 2012 C] 234 Biology\u201312","92.\tWhy has a bacterium to first become competent to \t98.\t(a)\tName the technique used for separation of be able to take up DNA? Explain how it becomes DNA fragments. competent and takes in the recombinant DNA. \t\t(b)\tWrite the type of matrix used in this \b [All India 2012 C] technique. \t 93.\tHow is the desired DNA for biotechnology \t\t(c)\tHow is separated DNA visualised and experiments first fragmented and later separated extracted for use in recombinant technology? by gel-electrophoresis? Explain. \b[All India 2010 C] \b [All India 2012 C] \t 99.\tName and explain the technique used in the separation and isolation of DNA fragments to be \t 94.\t(a)\t Why are restriction endonucleases so called? used in recombinant DNA technology. \t\t(b)\tWhat is a palindromic nucleotide sequence? \b [All India 2009] How do restriction endonucleases act on palindromic sites to create 'sticky ends'? \t100.\t(a)\tWhat is EcoRI? What does 'R' represent in this? \b[Delhi 2011] \t 95.\tEcoRI is used to cut a segment of foreign DNA \t\t(b)\tGive the palindromic nucleotide sequence recognised by it. and that of a vector DNA to form a recombinant DNA. Show with the help of schematic diagrams. \t\t(c)\t Explain its action.\b [Foreign 2009] \t\t(a)\tThe set of palindromic nucleotide sequence \t101.\tWhy are genes encoding resistance to antibiotics of base pairs the EcoRI will recognise in both considered useful selectable markers for E. coli the DNA segments. Mark the site at which cloning vector? Explain with the help of one EcoRI will act and cut both the segments. example.\b[Delhi 2009 C] \t\t(b)\t Sticky ends are formed on both the segments where the two DNA segments will join later \t102.\t(a)\tWhat are 'molecular scissors'? Give one to form a recombinant DNA.\b [Delhi 2010] example. \t 96.\t(a)\t Name the organism in which the vector shown \t\t(b)\tExplain their role in recombinant DNA is inserted to get the copies of the desired technology.\b[Delhi 2008] gene. \t103.\tRestriction endonucleases are used in genetic \t\t(b)\tMention the area labelled in the vector engineering to form recombinant DNA. Explain responsible for controlling the copy number only with the help of a flow chart the steps carried of the inserted gene. in the formation of a recombinant DNA. \t\t(c)\tName and explain the role of a selectable \b [CBSE 2022] marker in the vector shown. \t104.\tDNA being hydrophilic cannot pass through the EcoR I Cla I Hind III cell membranes of a host cell. Explain how does recombinant DNA get introduced into the host cell to transform the latter.\b [All India 2008] \t105.\t(a)\tGiven below is the stepwise schematic representation of the process of electrophoresis. Identify the \u2018alphabets\u2019 representing (i) Anode end (ii) smallest\/lightest DNA strand in the matrix (iii) Agarose gel Pvu I Pst I BamH I PQ R ampR Sal I pBR 322 4 \t\t\t end 3 end \b U S Ori Pvu II [All India 2010] 2 \t 97.\t(a)\t EcoRI is a restriction endonuclease. How is it 1 named so? Explain. T \t\t(b)\tWrite the sequence of DNA bases that the enzyme recognises. Mention the point at \t\t(b)\tWhat is elution? State the importance of which the enzyme makes a cut in the DNA elution in this process.\b [CBSE 2022] segment.\b[Delhi 2010 C] Biotechnology: Principles and Processes \u2009235","106.\t(a)\tExplain the significance of 'palindromic 5 Marks Questions nucleotide sequence' in the formation of \t110.\t(i)\tDescribe the characteristics a cloning vector must possess. recombinant DNA. \t\t(b)\tWrite the use of restriction endonuclease in \t\t(ii)\tWhy DNA cannot pass through the cell the above process.\b [All India 2017] membrane? Explain. How is a bacterial cell \t107.\tDescribe the roles of heat, primers and the made \u2018competent\u2019 to take up recombinant DNA bacterium Thermus aquaticus in the process of from the medium?\b [All India 2011] PCR.\b[All India 2017] \t111.\tIf a desired gene is identified in an organism for some experiments, explain the process of the \t108.\t(a)\tHow has the development of bioreactor helped in biotechnology? following: \t\t(b)\tName the most commonly used bioreactor \t\t(a)\t Cutting this desired gene at specific location and describe its working.\b [CBSE 2018] \t\t(b)\tSynthesis of multiple copies of this desired \t109.\tExplain the roles of the following with the gene help of an example each in recombinant DNA \t112.\t(a)\tDescribe the different steps in one complete technology: cycle of PCR. \t\t(a)\tRestriction Enzymes \t\t(b)\t State the purpose of such an amplified DNA \t\t(b)\tPlasmids\b [CBSE 2018] sequence. \b [All India 2011, 2015 C] Answers I. Multiple Choice Questions \t 9.\t Agarose, it acts as sieve and separates different size of DNA fragments when under the effect of \t 1.\t(b)\t 2.\t(a) \t3.\t(d)\t 4.\t(c)\t 5.\t(d) electric current. \t 6.\t(b)\t 7.\t(a)\t 8.\t(d)\t 9.\t(c)\t 10.\t(a) \t 10.\t Alien gene will lose the resistance towards II. Fill in the Blanks tetracycline due to insertional inactivation. \t 1.\tAgrobacterium tumifaciens \t 11.\t Plasmid of Agrobacterium tumifaciens carries the genes for tumour, \u2018Ti\u2019. Agrobacterium \t 2.\tcapsid\t\t\t 3.\tbacterial transfers these cancer causing genes in plants thus causing tumour. \t 4.\tintracellular \t 12.\t Retroviruses are disarmed and can be used as III. True or False vectors to deliver gene(s). \t 1.\tFalse\t 2.\tTrue\t 3.\tTrue\t 4.\tTrue\t 5.\tFalse \t 13.\t Alien gene will lose the resistance towards \t 6.\tTrue\t 7.\tFalse\t 8.\tTrue ampicillin due to insertional inactivation. IV. Match the items of Column I with those of \t 14.\t Plasmids are auto replicating body. When an Column II: alien DNA is linked to the plasmid, it also replicates along with it and copies of desired gene (A)\u2013(ii)\u2003 (B)\u2013(iv)\u2003 (C)\u2013(i)\u2003 (D)\u2013(iii) are formed. 1 Mark Questions \t 15.\t Restriction site linked with origin of replication. \t1.\t Agrobacterium tumifaciens is considered as \t 16.\t DNA ligase joins two segments of DNA natural genetic engineer as it has capability to transfer gene of interest into plants. \t 17.\t When an alien DNA is linked to the cloning, it also replicates along with it and copies of desired \t2.\tGel-electrophoresis gene are formed. It also helps us to distinguish between transformed and non-transformed cells. \t 3.\t Key tools for recombinant DNA technology It also transfers fragments of foreign DNA into a are restriction enzymes, polymerase enzymes, suitable host. ligases, vectors and the host organism. \t 18.\t A selectable marker helps us to distinguish \t4.\tEcoRI is restriction endonuclease enzyme. between transformed and non-transformed cells. Exonuclease removes nucleotides from the ends of DNA but EcoRI makes cuts little away from \t 19.\t DNA is negatively charged so it moves towards the centre within the specific DNA sequence anode (+ve charge) during gel electrophoresis. called recognition sequence. \t 20.\t The enzymes discovered were not allowing \t 5.\t By treating the bacterial cell with lysozyme. \t 6.\t Antibiotic resistance gene and plasmid vector of Salmonella typhimurium. \t 7.\t Animals cells \t 8.\t Plant cells 236 Biology\u201312","bacteriophage to grow in E. coli. One enzyme \t 26.\t Thermus aquaticus was adding methyl group to the DNA of E. coli \t 27.\t It is not possible as DNA cannot replicate and and other was cutting the DNA of bacteriophage multiply. It requires a specific sequence for its in culture of bacteria. replication called origin of replication. Alien DNA therefore joins with the host DNA with the \t 21.\t Exonucleases cut the DNA molecules at their help of an enzyme and links to ori to be a part of ends whereas endonucleases cut DNA molecules chromosome.\t within the specific sequence little away from centre. \t 28.\t Host is called as genetically modified organism or transgenic organism. The product is called as \t 22.\tM o l e c u l a r s c i s s o r s a r e t h e r e s t r i c t i o n recombinant protein. endonucleases which cut DNA at specific points. \t 29.\t Cellulase enzyme is used for digesting cell wall \t 23.\t Gel electrophoresis of plant cell which is made up of cellulose and \t 24.\t Ethidium bromide helps to visualize DNA under there is no such cell wall in animal cell.\t UV light. \t30.\t Plasmid is a self replicating circular extra- \t 25.\tThermostable Taq polymerase is isolated from chromosomal DNA present in some bacterial a bacterium, Thermus aquaticus, which remain active during the high temperature induced cells. denaturation of double stranded DNA. \t 31.\t The genes which code for Bt toxin \/ Cry proteins\u00a0\/ toxic proteins, Bacillus thuringiensis 2 Mark Questions \t32.\tDNA ligase enzyme joins the sticky ends of vector and foreign DNA. Sticky end G AAT T C CT TA A G Sticky end DNA fragments join at sticky ends \t33.\t Taq polymerase is a DNA polymerase enzyme provided in the reaction and the genomic DNA which is obtained from Thermus aquaticus as template. bacterium. This enzyme is thermostable i.e. it remains functional even at high temperature \t 37.\t Amplification of gene of interest is done by using induced denaturation of DNA during PCR. PCR. It follows the following steps. \t34.\tSimple stirred tank bioreactor. \t\t(i)\tDenaturation: DNA is denatured at high temperature i.e. 95\u00b0C for 15 seconds. \t\t It is used for large scale production of recombinant Separated strands act as each template. protein or enzymes by culturing bacteria or plant cells or animal cells which can express foreign \t\t(ii)\t Annealing: Two sets of primers are added at protein. 3' end of each strand. \t 35.\t Stanley Cohen and Herbert Boyer in 1972 \t\t(iii)\tExtension: DNA polymerase extends the constructed the first recombinant DNA. They primers using the nucleotide provided in isolated the antibiotic resistance gene by cutting the reaction. The above steps are repeated out a piece of DNA with restriction enzymes several time with the help of thermostable from the plasmid of a bacterium. The cut piece DNA polymerase (Taq). of DNA was then linked with the plasmid DNA of Salmonella typhimurium using DNA ligase. \t 38.\t Agrobacterium tumifaciens is of pathogenic The plasmid with alien DNA was now called as nature and causes tumour in the infected plants. recombinant DNA and was transferred to E. coli This is due to the Ti gene present in its plasmid. for cloning. This plasmid is modified by replacing Ti gene with the gene of interest which is now no more \t36.\t(i)\tThe process A is Denaturation of double pathogenic to host plants but is able to deliver stranded DNA. genes of interest in the plants. \t\t(ii)\t B are primers \t 39.\t Restriction enzymes cut strands of the DNA, a \t\t(iii)\tC is DNA polymerase or Taq polymerase. little away from the centre of the palindromic \t\t\t It extends the primers using the nucleotides sequence but between the same two bases on Biotechnology: Principles and Processes \u2009237","opposite strands. This leaves single stranded little away from the centre of palindromic overhangs stretches of DNA called sticky ends. sequence. This forms sticky ends which These sticky ends form hydrogen bonds with facilitates the ligation of foreign DNA. their complementary counterparts and aids ligation of two DNA fragments. \t 46.\t(a)\tThe transformants can be selected from the non-transformants by plating the \t 40.\t Ori is the site where replication starts. This site transformants on ampicillin-containing is responsible for controlling the copy number of medium. The transformants will grow in it, a vector. while the non-transformants fail to grow. \t \u2022\t Restriction site is the location on DNA where a \t\t(b)\t Ampicillin-resistant gene acts as a selectable specific restriction enzyme cuts it and at this site marker. the ligation of alien or foreign DNA occurs. \t 47.\t Bacteria are made competent to accept the DNA \t 41.\t Restriction nuclease cuts DNA at specific sites. or plasmid molecules. This is done by treating Nucleases are of two types: exonuclease and them with specific concentration of a divalent endonuclease. Exonuclease cuts DNA at the cation such as calcium to increase pore size in cell ends, whereas endonuclease reads the specific wall. The cells are then subjected to heat shock sequence called palindromes in DNA and treatment by incubating them with recombinant cuts the DNA little away from the centre of DNA on ice, followed by placing briefly at 42\u00b0C palindromic sequence. This forms sticky ends and then putting them back on ice again. which facilitates the ligation of foreign DNA. \t 48.\t(i)\tThe desired DNA segment is inserted into a \t 42.\t \u03b2-galactosidase gives blue colour in the presence cloning vector and the bacterial cell can be of chromogenic substance present in the bacterial made to take it up after making it competent culture medium. When an alien DNA is inserted by treating with specific concentration of within the coding sequence of an enzyme divalent cations such as calcium and then \u03b2-galactosidase, it results into inactivation of this giving heat shock treatment. gene. If transformation had occurred in bacteria, the colonies developed will be white but non- \t\t(ii)\tMicroinjection transformed colonies will be blue in colour. \t\t(iii)\tBiolistics or Gene gun \t 43.\t The palindrome in DNA is a sequence of base pairs that reads same on the two strands when \t\t(iv)\t Transformed disarmed pathogen orientation of reading is kept the same. For \t49.\t Refer answer no. 44 example, the following sequences reads the same on the two strands in 5'- 3' direction. This is also \t 50.\t(a)\tRefer answer 45 (a) true if read in the 3'- 5' direction. \t\t(b)\t EcoRI, Hind III \t\t 5' \u2014 \u2014 GAATTC \u2014 \u2014 3' \t 51.\t Ethidium bromide is nucleic acid dye which \t\t 3' \u2014 \u2014 CTTAAG \u2014 \u2014 5' gets intercalated with DNA. This DNA is then visualised under UV-light. \t 44.\t Since DNA is a hydrophilic molecule, it cannot pass through cell membranes. In order to force \t52.\t Ti plasmid is present in Agrobacterium bacteria to take up the plasmid, the bacterial tumefaciens. This has Ti gene which causes cells must first be made \u2018competent\u2019 to take up tumour in plants when they are infected by this DNA. Two ways by which a bacterial cell can be plasmid containing bacteria. This Ti plasmid is made competent are: modified by replacing tumour-inducing gene by desired gene. The bacteria transfers desired gene \t\t(i)\t By treating them with a specific concentration in plants upon infection. of a divalent cation such as calcium. \t 53.\t The vector DNA is cut using a specific restriction \t\t(ii)\tBy giving heat shock, bacteria is incubated enzyme at a particular site. Same restriction on ice, then at 42\u00b0C and then again on ice. enzyme is used to cut alien DNA segment. Both vector and alien DNA has similar sticky ends \t 45.\t(a)\t Exonuclease cuts DNA at the ends, whereas which are complementary to each other. This endonuclease cuts within the DNA. facilitates joining of both. Then DNA ligase is used to link both vector and alien DNA to form \t\t(b)\tEndonuclease reads the specific sequence recombinant vector. called palindromes in DNA and cuts the DNA \t\t Only one type of restriction endonuclease is required for creating recombinant vector because when cut by the same enzyme, the resultant 238 Biology\u201312","DNA fragments have the same sticky ends, \t\t\tRole of DNA polymerase is to extend the which can be joined together using DNA ligases. primers using the nucleotides provided in the reaction and the genomic DNA as template. Vector DNA Foreign DNA \t\t(b)\t Taq polymerase, it is obtained from Thermus GAA TTC G AATTC aquaticus. It is thermostable enzyme. CT T AAG C T TAAG \t 65.\t The technique to alter the chemistry of genetic EcoRI material and to introduce these into host organisms which ultimately change their Sticky end phenotypes is genetic engineering. GC \t\t Steps involved are: CT TA A AATT G \t\t(i)\t Isolation of DNA \t\t(ii)\t Cutting of DNA at specific locations Sticky end \t\t(iii)\tAmplification of gene of interest using PCR \t\t(iv)\tInsertion of recombinant DNA into the host DNA fragments join at sticky ends cell or organism Recombinant DNA \t\t(v)\t Obtaining the foreign gene product \t54.\t Refer answer no. 39. \t 66.\t Refer answer no. 63. \t67.\tThe naming of restriction endonuclease is as \t 55.\t(a)\t 3' \u2013 GAATTC\u20145' \t\t\t 5' \u2013 CTTAAG\u20143' follows: \t\t Such sequences are called palindromic sequences. \t\t(i)\tFirst letter is taken from the genus and next two letters from the species from where \t\t(b)\tEndonuclease reads the specific sequence enzyme is extracted. called palindromes in DNA and cuts the DNA little away from the centre of palindromic \t\t(ii)\t Roman number follows the name showing the sequence. This forms sticky ends which order from where the enzyme were isolated. facilitates the ligation of foreign DNA. \t\t\tExample: Eco RI derived from Escherichia \t56.\t Refer answer no. 42. coli Ry 13 and Hind II from Haemophilus influenxa Rd. \t 57.\t DNA is isolated by carrying out the following steps: \t68.\tRestriction endonuclease (EcoRI) inspects the length of the DNA sequence of both vector \t\t Purified DNA is isolated by treating bacterial or and foreign DNA\u2192The enzyme binds to the plant or animal cells with following enzymes: specific palindromic recognition sequence\u2192The enzyme performs a cut between G and A in \t\t(i)\t Lysozyme for bacterial cell the palindromic sequence when the sequence GAATTC is present in the DNA \u2192 Single \t\t(ii)\t Protease to degrade proteins such as histones stranded overhanging stretches called sticky ends are left to facilitate ligating other DNA \u2192 \t\t(iii)\tRibonuclease to degrade RNA The enzyme ligase joins host and foreign DNA strands at sticky ends to form recombinant DNA. \t\t(iv)\tThen pure DNA is precipitated by adding chilled ethanol. \t 58.\t Refer answer no. 38. \t 59.\t Natural source of agarose is sea weeds. Agarose provides a matrix base in which DNA fragments separate (resolve) according to their size through sieving effect provided by it. \t 60.\t(a)\tA: vector DNA, B: foreign DNA \t\t(b)\tEcoRI\t (c)\t DNA ligase The enzyme cuts both Eco RI cuts the DNA DNA strands at between bases G and A only \t 61.\t Replication starts at \u2018ori\u2019 and cloning site allows the same site when the sequence GAATTC restriction enzyme to cut DNA at this site where foreign DNA is inserted. is present in the DNA \t 62.\t Simple stirred-tank bioreactor and sparged Vector DNA Foreign DNA stirred-tank bioreactor. A bioreactor is used for large scale production of recombinant proteins GA A T TC G A A TT T C and biologically converting raw materials into CT T AAG specific products. C T TAAG EcoRI Sticky end \t 63.\t Thermus aquaticus. It is Thermostable at high G C temperature and can be used as only polymerase CT TA A AATT G enzyme for PCR. Sticky end DNA fragments join at sticky ends \t 64.\t(a)\t Two sets of primers are required in each cycle of PCR. Primers are required to allow the polymerase to start, because it can't just start by itself on a single stranded piece of DNA. Recombinant DNA Biotechnology: Principles and Processes \u2009239","69.\t The DNA fragments separated by gel electro\ufffd-\ufffd \t\t(b)\tRestriction enzyme cuts the DNA molecule phoresis can be visualized by staining them with at specific location with specific base pairs. ethedium bromide and then placing them under This specific sequence is called recognition ultraviolet radiations. For isolation, the agarose sequence. gel with desired band is cut and then purified DNA is extracted from the gel by a process called \t\t(c)\tGel electrophoresis is a technique where elution. fragments formed by cutting by RE are separated on the basis of their size. 3 Mark Questions \t 70.\t When the DNA is cut by RE many fragments \t 74.\t Refer answer no. 37. \t75.\t(a)\t(i) \u2018A\u2019 is sticky end of DNA are formed. These fragments can \t\t\t(ii) \u2018B\u2019 is origin of replication be separated by a technique called as gel \t\t(b)\t The term is palindromic sequence because the electrophoresis. The DNA fragments are separated on the basis of their size. The solid sequence of base pairs reads same on the two medium in which the fragments of DNA separate stands in both forward and backward. out is agarose gel. Agarose is extracted from a \t\t(c)\tPCR stands for polymerase chain reaction, it sea weed. The agarose gel acts as a sieve and amplifies the gene of interest in vitro. separates the fragments of DNA according to \t 76.\t Refer answer no. 68. their sizes. \t 77.\t Refer answer no. 69. \t l\tFragments of DNA are formed when it is \t78.\t(a)\t The cells are made competent so that they take up the hydrophilic DNA from the external subjected to restriction endonuclease digestion. medium easily. Calcium ions increase the efficiency of DNA entering the cell through \t l\tDNA is negatively-charged molecule. When pores in the cell wall. electric field is applied, DNA moves towards \t\t(b)\t Biolistic or Gene gun is used to introduce alien positively-charged anode through agarose gel DNA into the plant cell by bombarding them matrix. Agarose is a natural polymer extracted with high velocity micro-particles of gold or from a sea weed. When polymerized, agarose tungsten coated with DNA. forms gel and acts as a sieve which separates \t79.\t(a)\tAmpicillin-resistance gene and tetracycline- DNA according to the size of fragments. Small resistance gene are the selectable markers fragment will move faster than the larger in the cloning vector pBR322. They are used fragment. to identify and eliminate non-transformants and selectively permit the growth of the \t l\tDNA is visualized by staining it with Ethidium transformants. bromide (Et Br), otherwise it is not visible to \t\t(b)\t It is a simpler process and is less cumbersome. naked eyes. In the presence of chromogenic substrate recombinants are colourless and non- \t l\tBright orange bands of DNA are visible under recombinants are blue in colour which are UV light. easier to choose. Wells DNA bands \t 80.\t EcoRI inspects length of DNA and recognizes specific palindromic nuc-leotide sequence, binds Largest Smallest with DNA and cuts each of the two strands of double helix between A and G little away from 123 4 centre to form sticky ends. \t l\tDesired fragment is cut and purified from 5' GAATTC 3' agarose gel. This is called DNA elution. The extracted DNA is then subjected to the 3' CTTAAG 3' formation of recombinant DNA. \t 81.\t The correct sequence is Denaturation of ds- \t 71.\t Cloning sites are the single recognition sites DNA \u2192 Genomic DNA template \u2192 Chemically which are commonly used for restriction enzymes synthesized oligonucleotides\/primers \u2192 which the vector needs to link the alien DNA. Enzyme DNA-polymerase\/Thermostable DNA- polymerase (from Thermus aquaticus) \u2192 \t\t These sites plays a major role in joining DNA Nucleotides provided \u2192 Complementary region fragments of vector with alien DNA. Two cloning of DNA \u2192 In vitro synthesis of copies of DNA of sites of pBR322 are BamHI and PvuII. interest. \t 72.\t Refer answer no. 70. \t82.\t(a)\t a-ampicillin resistant gene, \t 73.\t(a)\t Plasmid DNA ligates the alien piece of DNA \t\t\td-tetracycline resistant gene, both are used with the constructed recombinant DNA. as selectable markers. It acts as a cloning vector in separation of recombinants and non-recombinants. 240 Biology\u201312","(b)\t b-galactosidase: it is simple and less \t 83.\t cumbersome process than using resistant genes as selectable markers. The b-galactosidase is an enzyme produced by galactosidase gene. When functional, it reacts with chromogenic substance and gives blue- coloured colonies, but if transformations occur, the colonies produced are white in colour due to insertional inactivation of the gene thus allowing visual selection of transformants from non-transformants. \t 84.\t Polymerase Chain Reaction (PCR) Multiple copies of gene of interest are sythesized in vitro. \t \tDNA template and two sets of primers, which are small, chemically-synthesized oligonucleotides that are complementary to the regions of DNA, Taq polymerase enzyme, (dNTPs) are used which make multiple copies in three steps. \t(i)\tDenaturation: Two strands of DNA separates by heating DNA. \t(ii)\tAnnealing: primers attach at complementary positions on DNA. \t(iii)\tExtension: Taq DNA polymerase adds deoxynucleotides and a new strand of DNA is synthesized. \t \tThe steps are repeated upto 30 cycles and 1 billion copies are produced. \t \tTaq polymerase is thermo-stable DNA polymerase isolated from bacterium Thermus aquaticus which remain active during high temperature-induced denaturation of double stranded DNA. \t \tThe amplified fragment of DNA obtained from PCR can then be ligated to a vector for further cloning. Region to be amplified 5' 3' dsDNA (a) Denaturation 3' 5' 5' Heat 5' 3' 3' 3' 5' Primers (b) Annealing of primers 3' 5' DNA polymerase 5' (Taq polymerase (c) Extension of primers 3' + deoxynucleotides) 5' 3' 3' 5' 3' 5' 30 cycles Amplified (~1 billion times) Polymerase Chain Reaction (PCR): Each cycle has three steps: (a) Denaturation, (b) Primer annealing and (c) Extension of primers. \t 85.\t Sparged-stirred-tank is used to produce large \t 86.\t(a) Ori: This is the site where replication starts volume of microbe or cellular culture which \t(b)\t Rop: Rop codes for the proteins involved in the expresses recombinant proteins. replication of the plasmid \t(c)\t Hind III : It is site at which restriction enzyme Hind III will cut the plasmid Increased Gas \t87.\tFor fig. Refer answer no. 83. surface area entrainment \t\tOri: This is the site where replication starts \t\tRop: Rop codes for the proteins involved in the for oxygen Air transfer replication of the plasmid Culture bubbles \t\t Genes encoding resistance to antibiotics are broth considered as selectable markers as they help in Stirrer identifying and eliminating non-transformants Supply of and selectively permitting the growth of the sterile air transformants. Biotechnology: Principles and Processes \u2009241","88.\t Refer answer no. 83. other vector DNA, cut with same RE by DNA \t89.\t(a) ligase. Fragments of DNA are formed when it is subjected to restriction endonuclease digestion. The enzyme cuts both EcoRI cuts the DNA DNA strands at between bases G and A only \t\t DNA is negatively-charged molecule. When the same site when the sequence GAATTC electric field is applied, DNA moves towards positively-charged anode through agarose gel is present in the DNA matrix. Agarose is a natural polymer extracted from a sea weed. When polymerized, agarose Vector DNA Foreign DNA forms gel and acts as sieve which separates DNA according to the size of fragments. Small GA A T TC G A A TT T C fragment will move faster than the larger CT T AAG fragment. C T TAAG \t\t DNA is visualized when stained with ethidium (b) bromide, otherwise not visible to naked eyes. Sticky end \t\t Bright orange bands are visible under UV light. G AAT T C \t\t Desired fragment is cut and purified from CT TA A G agarose gel. This is called DNA elution. The extracted DNA is then subjected to the formation Sticky end of recombinant DNA. \t90.\t( a ) D N A i s n e g a t i v e l y c h a r g e d . I n g e l \t 94.\t(a) Restriction endonuclease are the enzymes electrophoresis the fragments of DNA move produced by bacteria which does not allow foreign towards anode and separate according to size DNA to remain in cell by causing cleavage, thus under the influence of electric current. eliminating infecting organisms. \t\t(b)\tGel electrophoresis produces many DNA \t(b)\t Palindromic sequences are read same from both fragments which can be used to: sides. \t\t(i)\tConstruct a recombinant DNA molecule by \t\te.g. joining with the help of cloning vector. \t\t3\u2019\u2014GAATTC\u20145\u2019 \t\t(ii)\tAmplify using PCR (Polymerase chain reaction). \t\t5\u2019\u2014CTTAAG\u20143\u2019 \t91.\t(a) Restriction endonuclease recognizes the \t\t This sequence is recognised by restriction specific sequence on DNA and cuts at that site. enzyme EcoRI If same restriction enzyme is used to cut both \t\t RE inspects the length of DNA. When specific palindromic sequence is located by RE, it binds vector and foreign DNA, it facilitates the joining to DNA and cuts both the strands of DNA by breaking sugar phosphate backbone, little away of both DNA\u2019s at that particular region. from the centre but between same base sequence. This produces sticky ends. \t\t(b)\t Replication in DNA starts at ori \t 95.\t Refer answer no. 76. \t\t(c)\t Used to resolve DNA fragments according to \t 96.\t(a) E. coli size \t\t(b)\tOri \t 92.\t Since DNA is a hydrophilic molecule, it cannot \t\t(c)\tSelectable marker helps to identify transfor- pass through cell membranes. In order to force mants from non-transformants. bacteria to take up the plasmid, the bacterial \t97.\t(a)\t First letter of the name comes from the name of genus, E- \u2018Escherichia\u2019. Second two letters cells must first be made \u2018competent\u2019 to take up come from specific epithet, co \u2013 \u2018coli\u2019. The fourth capital letter comes from strain of the DNA. bacteria, R- \u2018R-strain\u2019. Roman numbers come from the order in which the enzymes were \t\t This is done by treating them with a specific isolated from the bacteria, I \u2013 \u2018enzyme is of order I\u2019 concentration of a divalent cation, such as \t\t(b)\tThe sequence is GAATTC. The cut is made calcium, which increases the efficiency with between G and A which DNA enters the bacterium through pores in its cell wall. Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 42\u00b0C (heat shock), and then putting them back on ice. \t 93.\t The desired DNA is fragmented via digestion of DNA by restriction endonucleases. RE inspects the length of DNA. When specific palindromic sequence is located by RE, it will bind to DNA and cut both the strands of DNA by breaking sugar phosphate backbone, little away from the centre but between same base sequence. This produces sticky ends and facilitates the joining of two DNA molecules, one desired and 242 Biology\u201312","98.\t(a)\t Gel electrophoresis (b) Agarose gel \t\t The selection of transformants can be carried \t\t(c)\tDNA is visualised by dye ethidium bromide out from non-recombinant ones by plating the transformants on ampicillin-containing medium. followed by exposure to UV light. It is The transformants growing on ampicillin- extracted by elution. containing medium are then transferred on a medium containing tetracycline. The \t 99.\t Refer answer no. 70. recombinants will grow in ampicillin-containing \t100.\t(a)\tStrain of the bacteria, R stands for R-strain medium but not on that containing tetracycline. But non-recombinants will grow on the medium of bacteria. containing both the antibiotics. \t\t(b)\tGAATTC \t102.\t(a) The restriction endonucleases are called \t\t (c)\t EcoRI cuts the DNA between bases G and A molecular scissors, as they cut the DNA segments at specific location, e.g., EcoRI cuts DNA between on both the strands only when the sequence bases G and A only when sequence GAATTC is GAATTC is present and recognised by EcoRI present in the DNA. in the DNA. \t(b)\t The restriction enzymes cut the DNA strands a \t101.\t Genes encoding resistance to antibiotics are little away from the centre of the palindromic considered as selectable markers as they help in sites, but between the same two bases on the identifying and eliminating non-transformants opposite strands. This leaves single stranded and selectively permitting the growth of the overhangs called sticky ends. These ends transformants. facilitate the action of the enzyme DNA ligase to join two DNA fragments. \t\t This is done by ligation of alien DNA at a restriction site present in any of antibiotic resistance genes. E.g. when foreign DNA is ligated at the BamHI site of tetracycline resistance gene in the vector pBR322. The recombinant plasmids will lose tetracycline resistance due to insertional inactivation. \t103. Diagrammatic representation of recombinant DNA technology. Biotechnology: Principles and Processes \u2009243","104.\t Recombinant DNA is introduced into the host agitator system is provided for even mixing of cell by the following methods: contents and oxygen. Air can also be bubbled through the reactor. Foam control system, \t\t(i)\t By Heat shock method where DNA is treated with temperature control system and pH control a specific concentration of a divalent cation, such system provide optimum growth conditions. as calcium, which increases the efficiency with Small amount of culture is withdrawn periodically which DNA enters the bacterium through pores through a sampling port. in its cell wall. The rDNA is forced into the cell by incubating the cell with rDNA on ice, followed Acid\/Base for Motor by placing them briefly at 42\u00b0C (heat shock) and pH control Foam braker then putting them back on ice. Steam for Flat bladed impeller \t\t(ii)\t By Micro-injection where the rDNA is directly sterilisation injected into the nucleus of an animal cell. Culture broth \t\t(iii)\tBy Gene gun or biolistics where cells are bombarded with high velocity micro-particles Sterile Air of gold or tungsten coated with desired DNA. \t109.\t(a)\t RE inspects the length of DNA \t105.\t(a)\t(i) Anode end-S (ii) R (iii) T \t\t\t When specific palindromic sequence is located \t\t(b)\t The separated bands of DNA are cut out from by RE, it will bind to DNA and cut both the the agarose gel and extracted from the gel strands of DNA by breaking sugar phosphate piece. This step is known as elution. backbone, little away from the centre but between same base sequence. This produces \t\tImportance: The DNA fragments purified in sticky ends. This facilitates the joining of two this way are used in constructing recombinant DNA molecules, one desired and other vector DNA by joining them with cloning vectors. DNA cut with same RE, by DNA ligase. \t106.\t(a)\t Restriction endonuclease cuts within specific \t\t\t Specific sequences are palindromic nucleotide palindromic sequence present in both vector sequence that read same both forward and and desired DNA sequence which help in the backward. formation of recombinant DNA. \t\t\t Example: For EcoRI specific sequence is \t\t(b)\t RE inspects the length of DNA. When specific palindromic sequence is located by RE, it DIRECTION OF READING will bind to DNA and cut both the strands of DNA by breaking sugar phosphate backbone, 5\u2019-GAATTC-3\u2019 little away from the centre but between same 3\u2019-CTTAAG-5\u2019 base squence. This produces sticky ends. This DIRECTION OF READING facilitates the joining of two DNA molecules by DNA ligase, one desired and other vector Cutting by EcoRI DNA, cut with same RE.. The resultant DNA is recombinant DNA which is then 5\u2019-GAATTC-3\u2019 inserted into desired host like E. coli. When 3\u2019-CTTAAG-5\u2019 this bacteria divides, the inserted DNA also divides along with the bacteria. Cutting by EcoRI \t107.\t Heat causes two DNA strands to separate. \t\t (b)\tPlasmids are autonomously replicating circular extra chromosomal DNA present in \t\t Primer helps the enzyme DNA Polymerase to bacteria which are responsible for various add nucleotides and extend the primers. characteristic features in bacteria such as providing antibiotic resistance to the bacteria. \t\t Thermus aquaticus is the source of Taq In the field of biotechnology, plasmids are polymerase used as cloning vectors which carry desired genes and express themselves. The plasmids \t108.\t(a)\tWe can obtain large quantity of foreign gene are also used to multiply the desired inserted product such as recombinant protein by gene in them. culturing the microbes which express them due to desired gene present in them. \t\t\tExample: Ti plasmid of Agrobacterium tumefaciens is used as a vector to transfer the \t\t(b)\t Most commonly used bioreactor is of Stirring desired genes in higher plants when linked to type. it. \t\tWorking \t\t Stirred-tank reactor is usually cylindrical large vessel with curved base which facilitates the mixing of the reactor contents. The stirrer or 244 Biology\u201312","5 Mark Questions \t u\tCloning sites: It is a site or sequence on vector DNA which is recognized by a restriction enzyme \t110.\t (i) A cloning vector must have following features: and is used to link alien DNA. Presence of many \t u\tOrigin of replication (ori): It is a sequence recognition sites within the cloning vector will complicate the gene cloning. where replication starts. When any alien DNA is inserted along with origin of replication, it \t (ii)\t Refer answer no. 44 & 104. replicates along with plasmid. Ori also controls \t111.\t (a) Refer answer no. 102 (a). copy number so a plasmid with high copy number \t(b)\t Refer answer no. 84. should be chosen. \t112.\t(a) Refer answer no. 84. \t(b)\tPurposes: \t u\tSelectable marker: It helps in identifying and eliminating non-transformants and allows \t(i)\t Gene therapy the growth of transformants. Commonly used selectable markers in E. coli are ampicillin \t(ii)\t DNA finger printing resistance genes, chloramphenicol resistance genes, tetracyclin or kanamycin resistance \t(iii)\t Prenatal diagnoses genes. \t(iv)\t Mutation diagnosis \t(v)\t Diagnosis of pathogens Assertion & Reason Type Questions For question numbers 1-8: Two statements are \t 4.\tAssertion: Selectable marker is meant for given one labelled Assertion (A) and the other labelled distinguishing a recombinant from non- recombinant. Reason (R). Select the correct answer to these questions \t \tReason: Every recombinant can flourish in from the codes (a), (b), (c) and (d) as given below. medium having both ampicillin and tetracycline, \t(a)\tBoth Assertion and Reason are true and Reason while the non-recombinants cannot. is the correct explanation of Assertion. \t 5.\tAssertion: Restriction endonuclease recognises palindromic sequence in DNA and cuts them. \t(b)\tBoth Assertion and Reason are true but Reason is NOT the correct explanation of Assertion. \t \tReason: Palindromic sequence has two unique recognition sites Pst I and Pvu I recognised by \t(c)\tAssertion is true but Reason is false. restriction endonuclease. \t(d)\tAssertion is false and Reason is also false. \t 1.\tAssertion: Bacterial cells are made competent \t 6.\tAssertion: Recombinant DNA technology has become successful because of the presence of by treating them with specific concentration of restriction endonucleases in eukaryotic cell. a divalent cation. \t \tReason: Treatment of bacterial cell with a \t \tReason: Restriction endonucleases cut the DNA divalent cation increases the efficiency with molecules to form blunt ends. which DNA enters the bacterium through pores in its cell wall. \t 7.\tAssertion: The cut pieces of DNA are linked \t 2.\tAssertion: Both the passenger and vehicle with plasmid DNA. DNAs are treated separately with separate restriction endonuclease. \t \tReason: Plasmid DNA fails to act as vectors. \t \tReason: Ligation is done by the use of alkaline \t 8.\tAssertion: Taq polymerase is used in PCR. phosphatase and DNA ligase. \t \tReason: Taq polymerase is extracted from \t 3.\tAssertion: Vector DNA and foreign DNA are cut by same restriction endonuclease. Thermus aquaticus, which is a thermostable \t \tReason: Digestion of vector DNA and foreign DNA with same enzyme produces complementary enzyme. sticky ends. \t 1.\t(a)\t Answers 5.\t(c) \t 6.\t(c)\t 2.\t(d)\t 3.\t(a)\t 4.\t(c)\t 7.\t(c)\t 8.\t(a) Case Based Questions Type III but only Type II restriction endonuclease are used in recombinant DNA Technology. \t1.\tRestriction endonuclease was isolated for the first Restriction endonuclease EcoRI recognises the time by W. Arber in 1962 in bacteria. Restriction base sequence GAATTC in DNA duplex and cut endonuclease cut the DNA duplex at specific strands between G and A. points therefore they are also called as molecular scissors or biological scissors. Three types of restriction endonucleases are TypeI, Type II and Biotechnology: Principles and Processes \u2009245","(i)\t Only type II restriction enzymes are used in \t\t(ii)\tWhich of the following depicts exonuclease gene manipulation because activity? (a) 5' \t\t(a)\t ATP is not required for cleaving \t\t(b)\t It consists of three different subunits \t\t\t 3' \t\t(c)\tIt makes cleavage or cut in both the strands of DNA molecule (b) \t\t(d)\t both (a) and (c) \t\t\t \t\t(ii)\tWhich of the following ions are used by restriction endonucleases for restriction? TT 5' \t\t(a)\tMg2+ ions\t (b)\tMn2+ ions \t\t(c)\tNa+ ions\t (d)\tK+ ions (c) \t\t(iii)\tRestriction endonuclease was isolated for the \t\t\t 3' first time in a \t\t(d)\t All of these \t\t(iii)\tCloning vectors are the DNA molecules that \t\t(a)\t Plant cell\t (b)\t Animal cell \t\t(a)\tCarry foreign DNA segment but do not \t\t(c)\t Prokaryotic cell\t (d)\t Germinal cell \t\t(iv)\tRestriction endonucleases are also called as replicate inside the host cell molecular or biological scissors because \t\t(b)\t Carry foreign DNA segment and replicate \t\t(a)\tThey cleave base pairs of DNA only at inside the host cell their terminal ends \t\t(c)\tTransfer nuclear DNA form nucleus to \t\t(b)\tThey cleave one or both the strands of the cytoplasm of the same cells DNA \t\t(d)\t Help in sealing gaps in DNA segments. \t\t(iv)\tTransfer of DNA into a eukaryotic cell is \t\t(c)\t They act only on single stranded DNA \t\t(d)\t None of these. called \t\t(v)\tSelect the option that correctly states the \t\t(a)\tTransformation working action of restriction endonuclease \t\t(b)\tTransduction \t\t(c)\tTransfection EcoRI on DNA sequence GAATTC. \t\t(d)\tElectroporation \t\t(v)\t Assertion: Three types of tools are used in (a) \u2193 \u2193 5\u2032 \u2212 GAATTC \u2212 3\u2032 \t(b) 5\u2032 \u2212 GAATTC \u2212 3\u2032 the formation of rDNA. 3\u2032 \u2212 CTTAAG \u2212 5\u2032 3\u2032 \u2212 CTTAAG \u2212 5\u2032 \t\t\tReason: These tools are yeast, cloning vectors \t\t\t \u2191 \t\u2191 and virus. \t\t(a)\tBoth assertion and reason are true and \u2193 \u2193 reason is the correct explanation of (c) 5\u2032 \u2212 GAATTC \u2212 3\u2032 5\u2032 \u2212 GAATTC \u2212 3\u2032 assertion. 3\u2032 \u2212 CTTAAG \u2212 5\u2032 (d)\t 3\u2032 \u2212 CTTAAG \u2212 5\u2032 \t\t(b)\tBoth assertion and reason are true but reason is not the correct explanation of \t\t\t \u2191 \t \u2191 assertion. \t\t(c)\t Assertion is true but reason is false. \t2.\tTools used in the formation of recombinant DNA \t\t(d)\t Both assertion and reason are false. are of three types. These are enzymes, cloning \t3.\tBioreactors are considered as vessels in which raw materials are biologically converted into vectors and competent host. Lysine enzymes are specific products by microbes, plant and animal cells or their enzymes. They are used for large used to extract DNA for experimental purpose scale production as they provide optimum growth conditions such as temperature, pH, substrate, from the cells. Cleaving enzymes break the DNA vitamins, oxygen and salts for obtaining desired product. Most commonly used bioreactors are of molecules. They are of three types: exonucleases, stirring type which include simple stirred tank bioreactor and sparged stirred-tank bioreactor. endonucleases and restriction endonucleases. A \t\t(i)\t Bioreactor are useful in \t\t(a)\t Amplifying a gene competent host is required for transformation \t\t(b)\t Isolation of genetic material \t\t(c)\t Processing large volume of culture with recombinant DNA and cloning vectors help \t\t(d)\t Infecting DNA in a cell. \t\t(ii)\tWhich of the following is essential to obtain to propagate DNA. desired product in a bioreactor? \t\t(i)\tWhich of the following is an example of natural lysing activity in a human body? \t\t(a)\tLysozyme present in tears dissolve the bacterial cell wall. \t\t(b)\tConversion of starch to maltose in the buccal cavity. \t\t(c)\tAbsorption of digested food into the intestinal cells. \t\t(d)\tConversion of protein molecules into amino acids in the stomach. 246 Biology\u201312","(a)\t Size of the bioreactor \t\tA different kind of vector is viral DNA. This type \t\t(b)\t Sterile condition of vector can usually accept much larger pieces \t\t(c)\t Quantity of the raw material of foreign DNA than plasmids can. After the \t\t(d)\t All of these DNA has been inserted into the viral vector, it \t\t(iii)\tAssertion: The stirred-tank is well suited can be cloned in the virus\u2019s host cells. The choice for large scale production of microorganisms of a suitable vector depends on many factors, under aseptic conditions. including the organism that will receive the new \t\t\tReason: In sparged stirred-tank bioreactor, gene and the size of the DNA to be cloned. surface area for oxygen transfer is increased. \t\t(i)\tThe most important feature that a vector \t\t(a)\tBoth assertion and reason are true and must have: reason is the correct explanation of \t\t(a)\t Small size\t (b)\t Presence of ori assertion. \t\t(c)\tPreservation\t (d)\tCircular \t\t(ii)\t Assertion : Viral DNA is used to transfer \t\t(b)\tBoth assertion and reason are true but reason is not the correct explanation of foreign DNA in human cell. \t\t\tReason: Viral DNA accept much larger pieces assertion. \t\t(c)\t Assertion is true but reason is false. of foreign DNA than plasmids can. \t\t(d)\t Both assertion and reason are false. \t\t\tOf the statements, mark the correct answer \t\t(iv)\t Growth condition that could affect the quality as of obtained product in a bioreactor are \t\t(a)\t If both Assertion and Reason are true and \t\t(a)\t Temperature and pH only Reason is the correct explanation of the \t\t(b)\t pH and oxygen supply only Assertion. \t\t(c)\t Temperature and oxygen supply only \t\t(b)\t If both Assertion and Reason are true, but \t\t(d)\t Temperature, pH and oxygen supply. Reason is not the correct explanation of \t\t(v)\t Vessels in which raw materials are biologically Assertion. converted into specific products are \t\t(c)\t If Assertion is true, but Reason is false. \t\t(a)\tBioreactors\t (b)\tFermentors \t\t(d)\t If both Assertion and Reason are false. \t\t(c)\t Gene guns\t (d)\t Both (a) and (b) \t\t(iii)\tDNA of a plasmid is \t4.\tA great variety of different types of DNA \t\t(a)\tCircular\t (b)\tOval molecules can serve as vectors, provided that \t\t(c)\tCylindrical\t (d)\tConical \t\t(iv)\t Assertion: Plasmids are widely used vectors. they have certain properties. The most important \t\t\tReason: The circular form of DNA molecules property is self-replication; once in a cell, a vector must be capable of replicating. Any DNA that is is important in protecting the DNA of the inserted in the vector will be replicated in the vector from destruction by the recipient of the process. Thus, vectors serve as vehicles for the vector. replication of desired DNA sequences. \t\t(a)\tBoth assertion and reason are true and \t\tVectors also need to be of a size that allows reason is the correct explanation of them to be manipulated outside the cell during assertion. recombinant DNA (rDNA) procedures. Smaller \t\t(b)\tBoth assertion and reason are true but vectors are more easily manipulated than larger reason is not the correct explanation of DNA molecules, which tend to be more fragile. assertion. Preservation is another important property of \t\t(c)\t Assertion is true but reason is false. vectors. The circular form of DNA molecules \t\t(d)\t Both assertion and reason are false. \t5.\tIn nature, plasmids are usually transferred is important in protecting the DNA of the vector from destruction by the recipient of the between closely related microbes by cell-to- vector. DNA of a plasmid is circular. Another cell contact, such as in conjugation. In genetic preservation mechanism occurs when the DNA of engineering, a plasmid must be inserted into a a virus inserts itself quickly into the chromosome cell by transformation, a procedure during which of the host. cells can take up DNA from the surrounding \t\tSome plasmids are capable of existing in several different species. They are called shuttle vectors environment. Many cell types, including E. coli, yeast, and mammalian cells, do not naturally and can be used to move cloned DNA sequences transform; however, simple chemical treatments among organisms, such as among bacterial, can make all of these cell types competent, or yeast, and mammalian cells, or among bacterial, able to take up external DNA. For E. coli, the fungal, and plant cells. Shuttle vectors can be procedure for making cells competent is to soak very useful in the process of genetically modifying them in a solution of calcium chloride for a multicellular organisms-for example, by trying to brief period. Following this treatment, the now- insert herbicide resistance genes into plants. competent cells are mixed with the cloned DNA Biotechnology: Principles and Processes \u2009247","and given a mild heat shock. Some of these cells \t6.\tThe process of selecting for genetically desirable will then take up the DNA. plants has always been a time-consuming \t\tA remarkable way of introducing foreign DNA into plant cells is to literally shoot it directly one. Performing conventional plant crosses is through the thick cellulose walls using a gene laborious and involves waiting for the planted gun. Microscopic particles of tungsten or gold seed to germinate and for the plant to mature. are coated with DNA and propelled by a burst Plant breeding has been revolutionized by the use of helium through the plant cell walls. Some of of plant cells grown in culture. Clones of plant the cells express the introduced DNA as though cells, including cells that have been genetically it were their own. altered by recombinant DNA techniques, can be \t\tDNA can be introduced directly into an animal grown in large numbers. These cells can then be cell by microinjection. This technique requires the induced to regenerate whole plants, from which use of a glass micropipette with a diameter that seeds can be harvested. \t\tRecombinant DNA can be introduced into plant is much smaller than the cell. The micropipette cells in several ways. Previously we mentioned punctures the plasma membrane, and DNA can be injected through it. protoplast fusion and the use of DNA-coated \t\tThus, there is a great variety of different \u201cbullets.\u201d The most elegant method, however, restriction enzymes, vectors, and methods of makes use of a plasmid called the Ti plasmid (Ti stands for tumor-inducing), which occurs inserting DNA into cells. But foreign DNA will naturally in the bacterium Agrobacterium survive only if it is either present on a self- replicating vector or incorporated into one of the tumifaciens. This bacterium infects certain plants, in which the Ti plasmid causes the formation of cell\u2019s chromosomes by recombination. a tumor like growth called a crown gall. A part \t\t(i)\tWhich cells are transformed using gene gun of the Ti plasmid, called T-DNA, integrates into method? the genome of the infected plant. The T-DNA \t\t(a)\t Bacterial cells\t (b)\t Plant cells \t\t(c)\t Animal cells\t (d)\t All of the above stimulates local cellular growth (the crown gall) \t\t(ii)\t Why calcium chloride is used to make the cell and simultaneously causes the production of competent? certain products used by the bacteria as a source \t\t(a)\t It makes the cell pores larger. of nutritional carbon and nitrogen. For plant \t\t(b)\t Increases the efficiency of DNA entering scientists, the attraction of the Ti plasmid is that it provides a vehicle for introducing rDNA the cell into a plant. A scientist can insert foreign genes \t\t(c)\t Promotes the binding of DNA to cell \t\t(d)\t None of these into the T-DNA, put the recombinant plasmid \t\t(iii)\tAssertion: Foreign DNA is transferred in back into the Agrobacterium cell, and use the bacterium to insert the recombinant Ti plasmid Plasmid vectors. into a plant cell. The plant cell with the foreign \t\t\tReason: DNA will survive only if it is either present on a self-replicating vector. gene can then be used to generate a new plant, \t\t(a)\tBoth assertion and reason are true and With luck, the new plant will express the foreign reason is the correct explanation of gene. Unfortunately, Agrobacterium does not naturally infect grases. assertion. \t\t(i)\tName the gene of the Agrobacterium \t\t(b)\tBoth assertion and reason are true but tumifaciens that causes crown gall disease. reason is not the correct explanation of \t\t(a)\t Ti Plasmid\t (b)\t Crown gall gene assertion. \t\t(c)\t T DNA\t (d)\t Tumour gene \t\t(c)\t Assertion is true but reason is false. \t\t(d)\t Both assertion and reason are false. \t\t(ii)\t Plant breeding has been revolutionized by: \t\t(iv)\t Assertion: Microinjection is a vector less \t\t(a)\t The use of hybridization techniques method of gene transfer. \t\t\tReason: DNA can be introduced directly into \t\t(b)\t The use of recombinant DNA technology an animal cell by this method. \t\t(c)\t The use of tissue culture technique \t\t(a)\tBoth assertion and reason are true and \t\t(d)\t None of the above. reason is the correct explanation of \t\t(iii)\tAssertion: Ti Plasmid of Agrobacterium tumifaciens cannot be used to improve potato assertion. plants. \t\t(b)\tBoth assertion and reason are true but \t\t\tReason: Agrobacterium does not naturally reason is not the correct explanation of infect grasses. assertion. \t\t(a)\tBoth assertion and reason are true and \t\t(c)\t Assertion is true but reason is false. reason is the correct explanation of \t\t(d)\t Both assertion and reason are false. assertion. 248 Biology\u201312","(b)\tBoth assertion and reason are true but Ans.\t 1.\t(i)\t(d)\t(ii)\t(a) reason is not the correct explanation of \t\t\t(iii)\t(c)\t(iv)\t(b) \t\t\t(v)\t(b) assertion. \t\t2.\t(i)\t(a)\t(ii)\t(c) \t\t\t(iii)\t(b)\t(iv)\t(c) \t\t(c)\t Assertion is true but reason is false. \t\t\t(v)\t(c) \t\t(d)\t Both assertion and reason are false. \t\t3.\t(i)\t(c)\t(ii)\t(b) \t\t(iv)\t Assertion: Agrobacterium tumifaciens cannot \t\t\t(iii)\t(b)\t(iv)\t(d) \t\t\t(v)\t(d) be used in animal cell. \t\t4.\t(i)\t(b)\t(ii)\t(b) \t\t\t(iii)\t(a)\t(iv)\t(a) \t\t\tReason: This bacterium infects certain \t\t5.\t(i)\t(b)\t(ii)\t(c) plants only, in which the Ti plasmid causes \t\t\t(iii)\t(a)\t(iv)\t(b) the formation of a tumor like growth called a \t\t6.\t(i)\t(c)\t(ii)\t(c) \t\t\t(iii)\t(d)\t(iv)\t(b) crown gall. \t\t7.\t(i)\t(a) Thermostable DNA polymerase \t\t(a)\tBoth assertion and reason are true and isolated from a bacterium Thermus reason is the correct explanation of aquaticus, which remain active during the high temperature induced denaturation assertion. of double stranded DNA. \t\t\t(b)\tPrimer is a small segment of DNA that \t\t(b)\tBoth assertion and reason are true but binds to a complementary strand of reason is not the correct explanation of DNA. Primers are necessary to start the functioning of DNA polymerase assertion. enzyme and therefore are necessary in polymerase chain reaction. \t\t(c)\t Assertion is true but reason is false. \t\t\t(c)\t PCR is important because it can generate \t\t(d)\t Both assertion and reason are false. several copies of a DNA sequence in a very \t 7.\t (i)\t Enzyme Taq polymerase, is extracted short time period. It is also important in forensic science as a tool for genetic from a eubacterial microorganism Thermus engineering. It helps in analyzing the aquaticus from Yellowstone National Park gene expression. in Montana, USA and isolated by Chien et al. OR (1976). Taq polymerase successfully replaced \t\t(ii)\t(a)\t ADA deficiency \t\t\t(b)\tAs a first step towards gene therapy, the DNA polymerase from E.coli that was being used in PCR earlier and this shift lymphocytes from the blood of the patient are grown in a culture outside the body. A revolutionised the PCR technique. functional ADA cDNA (using a retroviral \t\t(a)\tTaq polymerase after its discovery vector) is then introduced into these lymphocytes, which are subsequently replaced E.coli DNA polymerase in PCR returned to the patient. However, technique. Explain giving reasons why as these cells are not immortal, the was the need felt for the change? patient requires periodic infusion of such \t\t(b)\tWhat is a primer and its importance in genetically engineered lymphocytes PCR? \t\t\t(c)\tIf the gene isolate from marrow cells \t\t(c)\tWrite the importance of PCR as a producing ADA is introduced into cells diagnostic tool.\b[CBSE 2022] at early embryonic stages, it could be a permanent cure. OR \t\t(ii)\tBiotechnology revolves around the \u2018\u2018gene of qqq interest\u2019\u2019, with an objective to open various avenues for human welfare in health, medicine, pharma, agriculture etc. using different techniques, tools and processes. One of the breakthroughs of biotechnology in medicine is the gene therapy. \t\t(a)\tName the human disease for which the gene therapy was used for the first time. \t\t(b)\t Explain the steps of gene therapy carried to cure the disease using the lymphocytes of the patient. Why is this therapy not a permanent cure of the disease? \t\t(c)\t Write the possible permanent cure of the disease by the gene therapy that is in progress. Biotechnology: Principles and Processes \u2009249"]
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