Science 2 part 1

IISCIENCE PART 1

Module 1 Nature of Biology What this module is about This module was designed and written with you in mind. It is here to help you masterthe nature of Biology. The scope of this module permits it to be used in many differentlearning situations. The language used recognizes the diverse vocabulary level of students.The lessons are arranged to follow the standard sequence of the course. But the order inwhich you read them can be changed to correspond with the textbook you are now using. The module is divided into three lessons, namely:  Lesson 1 – Biology: The Science of Life  Lesson 2 – Biological Concepts as Applied in Technology  Lesson 3 – Tools Used in the Development of Biology and Biotechnology What you are expected to learn After going through this module, you are expected to: 1. identify the unifying ideas in biology; 2. explain the different life processes; 3. explain biological concepts in a given technology; 4. identify the parts and function of the microscope; 5. name special tools used in research and technology; and 6. describe the contributions of Filipino and foreign scientists in the field of biology and technology. How to learn from this module This may be a new type of instructional material for you. Its subject matter has beenbroken down into a series of manageable blocks. The given activities are importantbecause they are programmed to help you learn more efficiently.

Some topics present new information; others review materials that you may alreadyknow. Every block presents a learning task that requires some response from you. When you have written or marked your answer, you will want to find out whether youranswers were right. The module provides you with important feedback by giving you easyaccess to the answers. Do not look at the correct answer until after you have marked yourown answers. If you look before answering, you will only impair your own learning process. If your answer is wrong, reread the lesson until you understand your error. Then goon.What to do before (Pretest)Multiple Choice. Choose the letter of the best answer. Write the chosen letter on aseparate sheet of paper.1. The process by which animals take in foods that have already been manufactured fromraw materials isa. digestion c. nutritionb. ingestion d. photosynthesis2. The process by which digested foods are passed into different parts of a plant or ananimal isa. digestion c. nutritionb. ingestion d. absorption3. The process by which oxygen is taken into an organism and carbon dioxide is eliminatedfrom the organism is calleda. excretion c. circulationb. secretion d. respiration4. The building-up and breaking down processes occurring in animals isa. excretion c. metabolismb. secretion d. assimilation5. Learning the bones of the human body would be a part ofa. anatomy c. embryologyb. cytology d. physiology6. The process by which food is broken down into simpler substances is calleda. digestion c. ingestionb. excretion d. respiration -2-

7. Growth occurs due to a (an) a. increase in the metabolism b. increase in the size of cells c. increase in number of cells d. lowering in the rate of cell division8. What is the smallest, most basic unit of life?a. cell c. tissueb. system d. element9. Which of these processes produce genetically identical organisms?a. cloning c. colchicineb. grafting d. hybridization10. What is the process that allows millions of copies of DNA to be produced?a. PCR c. DNA fingerprintingb. recombinant DNA d. gel electrophoresis11. Two sections of DNA that are joined together forma. a PCR c. a cloneb. ligase d. recombinant DNA12. Exact copies of DNA as a result of asexual reproduction area. clones c. complimentary basesb. splices d. recombinant sequences13. What do you call the circular pieces of DNA found in bacteria?a. clones c. plasmidsb. ligase d. endonucleases14. What chemicals are used to cut DNA into fragments?a. clones c. plasmidsb. ligases d. restriction enzymes15. The quality of a microscope is judged by itsa. light strength c. magnification powerb. resolving power d. volumetric capacity16. Which microscope uses lenses and objectives to magnify? a. atomic force microscope b. compound light microscope c. scanning electron microscope d. transmission electron microscope17. Who was the scientist who gave the name cells to structures?a. Hooke c. Virchowb. Schwann d. Schleiden -3-

18. Who developed the modern system of classification?a. Hooke c. Darwinb. Carson d. Linnaeus19. Who was the “founder“ of biology? c. Aristotle a. Hooke d. Leeuwenhoek b. Darwin20. Mendel became famous for his study of c. heredity a. zoology d. bacteriology b. cytology Key to answers on page 20.Lesson 1. Biology: The Science of LifeBiology Defined Biology is the science that studies life and living things, including the laws that governthe phenomena of life. Every aspect of life from the smallest submicroscopic living particle to the largest andmost imposing of plant and animal species is included in the study of biology. Biologicalstudy encompasses all that is known about any plant, animal, microbe or other living thing ofthe past or present. Biology is a natural science because it is the study of organic (living) nature. It is thescience of fishes and fireflies, grass and grasshoppers, humans and mushrooms, flowersand sea stars, worms and molds. It is the study of life on top of the highest mountain and atthe bottom of the deepest sea. Biology is the accumulated knowledge about all living thingsand the principles and laws that govern life. Those who specialize in biology are known asbiologists or naturalists, and it is through their observations of nature and naturalphenomena that the great ideas of biology have been born.Branches of Biology The amount of knowledge gained in biology is so large that it has many branches.The following table lists some of the major ones. -4-

Table 1. Some Branches of BiologyName FocusBotany plantsZoology animalsAnatomy structure of living thingsTaxonomy classification of living thingsCytology cells, their structure and functionsGenetics heredityPhysiology functions of living thingsMicrobiology living things at microscopic levelUnifying Ideas in Biology1. There is an underlying unity in the world of life, for all organisms are alike in key respects. They consist of the same kinds of substances, put together according to the same laws that govern matter and energy. Their activities depend on input of energy, which they must obtain from their environment. All organisms sense and respond to changing conditions in their environment. They all grow and reproduce, based on the instructions contained in their DNA.2. There is also an immense diversity in the world of life. Millions of different organisms inhabit the Earth. Many millions more lived and became extinct over the past 3.8 billion years. And each kind of organism is unique in some of its traits – that is, in some aspects of its body plan, body functions, and behavior.3. Theories of evolution, especially the theory of natural selection as first formulated by Charles Darwin, help explain the meaning of biological diversity.4. Biology is a science. It is based on systematic observations, hypotheses, predictions, and relentless tests. The external world, not internal conviction, is the testing ground for scientific theories.Life Processes It is usually easy to recognize life, but it is often much harder to define it. All livingthings are made of cells. Some organisms are unicellular and consist of only a single cell.Other organisms are multicellular and are composed of many cells. To determine whetheran object is living or nonliving, biologists have agreed on several characteristics that defineliving things. They are referred to as life processes or activities. These life processesinclude such activities as growth, metabolism, movement, and reproduction. Living thingsalso react, or respond, to their environment. The ability to respond to an environmentstimulus is called irritability (no, this word does not mean cranky in this case). Living things grow. Growth is an increase in size. Most organisms also go through aseries of changes called development. The beginning form of an organism may not -5-

resemble its adult form. For example, a tadpole does not look the same as an adult frog.Growth in multicellular organisms is due to an increase in the number of cells. Humansbegin life as a single cell. However, when they are adults, they consist of even more cells. Metabolism refers to the chemical activities that are needed for life. Ingestion,digestion, respiration, and excretion are the processes of metabolism. Ingestion is taking infood. The process of breaking down food into simpler substances is called digestion. Thebreaking down of food particles to release energy is called respiration. For biologists,respiration has two meanings. Respiration occurs at the cellular level when food is brokendown to release energy. Respiration is also the process of taking in oxygen and giving offcarbon dioxide as a waste gas. In humans, breathing and respiration often refer to the sameprocess. Excretion is getting rid of wastes. Excretion usually refers to the removal of solidand liquid metabolic wastes that are produced during respiration. Catabolism and anabolism are two processes in living things that are involved inmetabolism. Catabolism is the break down of complex substances into simpler substances.Anabolism is the formation of complex substances from simpler substances. Reproduction is the process of producing new organisms of the same kind.Reproduction of living things can occur asexually, requiring only one parent, or sexually,requiring two parents. Organisms that consist of a single cell reproduce asexually bydividing. Organisms that reproduce sexually contain genetic material contributed from eachparent. If a group of living things does not reproduce, extinction of that group occurs. Living things react to changes in their environment. A response is a reaction to achange. Responding to a change in the environment may increase an organism’s ability tosurvive. Organisms must be able to get and use energy in order to survive. Energy is neededto carry out all cellular processes. For example, organisms use energy from food to grow,develop, and reproduce. Energy flows through individual animals, communities, and the environment. It ispassed from one organism to another organism, usually in the form of food. For example, agoat eats the energy from the sun that is contained in the cells of a plant. Man then eats thegoat and gets its energy. In this way, energy moves through living systems from oneorganism to another. The sun is the ultimate source of energy, for most of the organismsthat live on Earth, although there are exceptions. Some bacteria for example, are able touse the energy trapped in chemical compounds rather than the energy from the sun asplants do. Living things are highly ordered. A tree grows into a form typical of its species. Allhumans have the same general form, although there are differences in size. The chemicalreactions that occur in living things do not occur randomly. The chemicals that make upliving organisms are, in general, more complex than the chemicals found in nonliving things,such as rocks. All living things are complex. All are composed of small units of life calledcells. Cells are able to carry out all the life processes that insure their survival. -6-

What you will doActivity 1.1 Understanding Science Words There are two ways you can understand science words better. One way is bydefining the word in context. The way the word is used gives you a clue as to its meaning.Another way is by looking at the parts that make up the word. Each word part can give youa clue as to the meaning of the whole word.Learning the Skill: Defining Words in Context1. First, read to see if the word is defined directly in the sentence.2. If the word is not defined directly, read several sentences beyond the one in which the word first appears. These sentences may provide information about the definition of the word.3. If possible, define the word based on your own past knowledge. You may have learned the word in an earlier grade, or you may be familiar with it because you hear it everyday.4. Figure out the meaning of the word by how it is used in the sentence and by the sentences around it.Find the definitions of the italicized words.1. Biology is the study of life.2. A cat is a mammal.3. All living things can reproduce4. Green plants carry out photosynthesis.Learning the Skill: Understanding Word Parts1. Look at the word to see how many word parts you think it has. The word may have one or more word parts.2. You may recognize parts of the word from previous lessons. Or, you may recognize parts of the word from other familiar words. Try to define each word part if you can. Then define the whole word.3. Look for root words and prefixes or suffixes. A root word is the main part of the word. A prefix is a word part added to the front of a root word to change its meaning. A suffix is a word part added to the end of a root word to change its meaning.Now try the following:1. What does the word microorganism mean? The word microorganism has two wordparts, micro and organism. You remember the word microscope and that micro meanssmall. You also remember that the word organism means a living thing.2. Examples of root words are:emia- blood bio- lifevertebrate- animal with a backbone zoo- animal -7-

3. The prefixes an and in mean without. What do the words anemia and invertebrate mean?4. The suffix logy means the study of. What is biology? Zoology?What you will doSelf-Test 1.1Use a separate sheet of paper to write down your answers.Matching Type. Write the letter of the item in column B that most closely matches the itemin column A. A B1. a child gains four kilograms2. heartbeat rate increases during exercise a. development3. a tadpole becomes a frog b. growth4. the number of organisms in a community c. homeostasis d. reproduction increases5. dogs produce dogs6. a tree trunk gets thicker as the tree becomes older7. a dog pants when it is hot8. a seed changes form in becoming a plant9. zoology e. plants10. anatomy f. animals11. physiology g. structure of the body12. ecology h. organisms and their environment13. botany i. functions of the body14. growth j. forming complex substances15. cell k. the smallest unit of life16. catabolism l. breaking down complex substances17. anabolism m. producing organisms of the same kind18. reproduction n. an increase in size Key to answers on page 20. -8-

Lesson 2. Biological Concepts as Applied in TechnologyBiotechnology One of the new and revolutionary areas of biological research is the field ofbiotechnology. Biotechnology is “applied biological science” such as the use of the geneticmaterial in living organisms to help make useful products or to solve medical problems. Theuse of biotechnology has affected many practices in agriculture, criminal investigations, andthe ways we diagnose and prevent human diseases. Biotechnology is a combination of several different technologies. Even thoughbiotechnology is a new word, the concept behind biotechnology is very old. Throughouthistory, people selected strains of bacteria and yeasts that were useful in producing certainfood products. For example, they used yeast to make bread. Yeast is a microscopicorganism related to mushrooms and the fungi that cause diseases such as athlete’s footand ringworm. Various kinds of bacteria were used to produce cheeses and yogurt.Bacteria are also living organisms. By making observations and through trial and error,these selections could certainly be considered early uses of biotechnology.Genetic Engineering To date, more than one hundred fifty products produced by biotechnology are beingused in medicine and agriculture. Another hundred or more new products are in variousstages of development. So you can see that biotechnology may soon influence your lifemore than any other technology will. As you read on, you will discover some of the othercontributions of biotechnology. Scientists use biotechnology in much more sophisticated ways today. Scientists canactually use microorganisms to make many biologically important substances. For example,most genetic research is done at the molecular level. Scientists are now able to manipulategenes of living organisms. This technique is usually called genetic engineering. Manytimes, genes are actually moved from one DNA molecule and inserted into another. Thenew DNA molecule is called recombinant DNA.Scientists are able tocombine two different DNAfragments through the use ofrestriction enzymes. Usingrestriction enzymes like a pair ofchemical scissors, scientists cut astrand of DNA at particular point inthe sequence of bases. The pointwhere the sequence is cut by therestriction enzyme is called the Figure 2.1 Bacterium with plasmidsrestriction site. Scientists then -9-

remove the fragment of DNA that contains a specific gene and insert that section into a newDNA molecule. The DNA fragment cannot function by itself; it must be inserted into theDNA of an organism. After insertion, the open areas of the DNA have to be closed. Ligasesare enzymes used to join the pieces of DNA. The process by which a section of DNA from one organism is inserted into the DNAof another organism is called gene splicing. It is easiest to insert the DNA fragments intothe DNA material present in bacterial cells. Plasmids, or circular pieces of DNA in bacteria,usually serve as the site of insertion for sections of DNA. Since bacteria reproduce veryquickly, many copies of the recombinant gene can be made in a short time. Cloning isasexual reproduction that produces identical copies of the DNA. Figure 2.2During the formation of recombinant DNA, a plasmid from a bacterium, such as E. coli, is snipped open. Ashort piece is then removed from the DNA of a human cell. This human DNA is inserted to the snippedbacterium plasmid. Then the plasmid is placed back into the bacterium. In order to manipulate DNA, scientists need to study the individual fragments of DNAthey are working with. Gel electrophoresis is a method used to separate DNA fragments.This technique uses agarose gel and an electric current. DNA is placed in the gel, and anelectric current is run across the gel. Because DNA fragments are negatively charged, theymove towards the positively charged areas in the agar. Small fragments of DNA move fasterthan larger fragments. Thus, based on its rate of migration, the size of the DNA fragmentcan be calculated. Many copies of a specific segment of DNA can be made through a process called apolymerase chain reaction (PCR). In cloning techniques, PCR is used to increase theamount of DNA. It has also been used to help diagnose human genetic disorders. Whenonly small amounts of DNA are available, PCR is used to increase the size of the sample foreasy analysis. - 10 -

DNA Fingerprinting One aspect of biotechnology deals with DNA that is used to identify a person.Traditionally, identification has been made by identifying fingerprint patterns. Since no twopeople (except identical siblings) have exactly the same DNA sequence, it is possible to usethese unique sequences as a means of identifying a person. This new technique hasbecome known as DNA fingerprinting. This process is often used to compare a sample ofDNA found in tissues collected at a crime scene with the DNA of the suspect. Many people are concerned that certain applications of biotechnology will lead topossible abuses of individual rights. Decisions about the use of biotechnology often involvevalue judgments that will have to be decided by society. While we debate the uses andconsequences of biotechnology, many benefits to society have already been achieved usingthese techniques, and new discoveries are being made daily.What you will doSelf-Test 2.1Use a separate sheet of paper to write down your answers.A. Matching TypeDirection: Write the letter of the item in column B that most closely matches the item incolumn A. A B1. genetic engineering a. determining order of bases in DNA2. DNA fingerprinting b. process to separate DNA fragments3. gel electrophoresis c. making copies of DNA4. PCR d. manipulating the genes of living organisms5. DNA sequencing e. allow scientists to compare DNA sequencesB. Fill in the blanks1. Gel electrophoresis works because DNA has a ________ charge.2. Using gel electrophoresis, the size of a DNA fingerprint can be calculated by its rate of ___________.3. The process that takes a section of DNA from one organism and inserts it into the DNA of another organism is called gene __________.4. ___________ is the use of living organisms to help solve problems or make useful products.5. The specific point where a restriction enzyme cuts a DNA sequence is called its ___________. Key to answers on page 21. - 11 -

Lesson 3. Tools Used in the Development of Biology and Biotechnology The subject of this lesson is the MICROSCOPE. The microscope is a tool used tostudy objects too small to be seen with the unaided eye. You will be using the microscopeto discover a whole world of life too small to be seen with the eye alone. The study of thediversity of life will begin with microscopic organisms and progress to the largest organism. The microscope enlarges the image of a small object. In your biology class, you willbe using the compound microscope. It consists of two lenses, each fitted into the end of atube within a tube.How to Prepare the Microscope The word microscope comes from the Greek word micro meaning “small” andscopein meaning “to see or view.” The purpose of a microscope is to magnify small objectsso that they can be seen. The microscope that you will be using is both a light and a compound microscope.The light for your microscope will come from sunlight. The word compound refers to amicroscope with two lenses or a set of lenses. There are two sets of lenses in amicroscope, one at each end of the body tube. The two sets of lenses are called theEYEPIECE and the OBJECTIVE.How to Focus the Microscope The purpose of adjusting or focusing the microscope is to produce a magnified imagethat is sharp. That is where the problem begins. Do not be surprised if you do not get sharpimages at once. The scientific word for focusing to get a sharp image is RESOLUTION.MAGNIFICATION is the enlarging of an image. Resolution and magnification are twodifferent things. The problem is that you cannot get good resolution and good magnificationat the same time. A microscope may have to be continually adjusted to get a sharp picture. This isespecially true when you are viewing living things. They swim up and down in a drop ofwater. As an organism moves in a drop of water, it will go out of focus. Turn the adjustmentknob to bring the image back into focus.The Limitations of a Microscope1. Resolution limits magnification.2. Continual focusing is necessary if the object moves.3. Image will be upside-down and reversed. - 12 -

Microscope Parts and Their Functions1. Arm. Supports the body tube.2. Eyepiece. Contains the Eyepiecemagnifying lens you look through.3. Body tube. Maintains the properdistance between the eyepieceand objective lens.4. Nosepiece. Holds objective lens. Coarse adjustment5. Objective lens. A lens which Body tubeusually provide a 10x or a 20xmagnification.6. Stage clips. Hold the slide inplace. Objective Stage clip7. Stage. Supports the slide being Stage Baseviewed. Diaphragm Mirror8. Diaphragm. Regulates theamount of light let into the bodytube.9. Mirror. Reflects the light upwardthrough the diaphragm, thespecimen, and the lenses.10. Base. Supports the microscope.11. Adjustment knob. Moves thebody tube up and down for Figure 3.1 Compound Light Microscopefocusing.Other Tools of the Biologist In the 1930s, scientists developed the first electron microscope. This type ofmicroscope used beams of electrons, instead of light, to make an image. Today, there aretwo types of electron microscopes, the transmission electron microscope (TEM) and thescanning electron microscope (SEM). In the TEM, electrons actually pass through the objectbeing viewed. The biologist sees a thin, flat view of the structures of a specimen. The SEMgives the biologist a surface view of a specimen by coating the specimen with metal,causing the electrons to bounce off the surface. Special detectors pick up the electrons andconvert them on a television screen. Computers have also increased our knowledge by storing and processing greatquantities of data.Biologists at Work The following is a brief list of people who made contributions to the body of biologicalknowledge. - 13 -

Anton van Leeuwenhoek, a Dutch lens maker, is credited with making the firstmicroscope. Leeuwenhoek was the first person to observe microscopic organisms. Robert Hooke was an Englishman who observed cork – the protective layer of cellsproduced by trees – under a microscope. He noticed that the cork sample was divided intosmall chambers. He called these chambers cells. Supposedly, they reminded him of thecells, or rooms, in a monastery. Today, the word cell describes the smallest structural unitof all living things. Carolus Linnaeus was a Swedish botanist who developed the system for namingorganisms used by biologists. Known as binomial nomenclature, this system links a uniquegenus and species name to every type of living thing. These two names are used byscientists all over the world to describe particular organisms. Before this system wasdeveloped, people used many different names for the same organism. Linnaeus‘s workbrought order to what was previously a chaotic situation. Charles Darwin was the British scientist who developed the idea of natural selection,which led to his famous theory of evolution. Darwin’s theory recognizes that life has existedon Earth for a very long time, and has changed over time to produce the many types ofliving things we observe today. Gregor Mendel was an Austrian monk whose work formed the basis for the modernscience of genetics. Mendel’s work with pea plants enabled him to develop the basic lawsthat are used to explain the inheritance of traits. Matthias Schleiden, a botanist, and Theodor Schwann, a zoologist, madeobservations that led to the “cell theory”. The cell theory states that: all living things aremade up of cells; cells are the basic unit of structure and function of all living things; and allcells come from preexisting cells. James Watson, an American biologist, and Francis Crick, a British physicist,discovered the structure of DNA. DNA is the nucleic acid that stores information needed forall cellular activities. Their work was based, in part, on the brilliant X rays of DNA taken bybiochemists Rosalinda Franklin and Maurice Wilkins. Rachel Carson, an American writer and biologist, warned of the danger of theincreased use of pesticides and the damage it was doing to nature. This brilliant scientificwriter attracted a large audience. Her book Silent Spring made Americans aware of ecologyand the concept that all living things are important because their lives are interconnected inmany ways. Jacques-Yves Cousteau, a French ocean explorer, is the co-inventor of theaqualung. This device revolutionized underwater exploration by making it easier for peopleto explore the world of ocean life. He introduced the general public to life in the sea throughhis books and films. - 14 -

The following are outstanding Filipinos who have made a large contribution tobiological knowledge. Lourdes J. Cruz. Her researches have contributed to the understanding of thebiochemistry of toxic peptides from the venom of fish-hunting Conus marine snails. Thecharacterization of over fifty biologically active peptides from the snails’ venom had beenmade possible, in part, by her studies. Also, her work led to the development of conotoxinsused as tools for examining the activity of the human brain. For instance, w-Conotoxin iswidely used for studying neural calcium channels and m-Conotoxins is used when muscularactivity must be controlled to examine events at the synapse. Clare R. Baltazar is the author of Philippine Insects, the first authoritative text onPhilippine insects. Her numerous works on insects, especially on the PhilippineHymenoptera, are significant in laying down the framework of insect control in the future.She also discovered one subgenus of Hymenoptera and one hundred eight new species ofthe Philippine parasitic wasp. Magdalena C. Cantoria. Dr. Cantoria’s researches focused particularly on themorphology, physiology, and biochemistry of drug plants. She has also done basic study onthe pharmacognosy (or the study of the therapeutic substances) of agar, raulfia, datura,mint, and piper species. Filomena F. Campos is recognized for her work on cotton research in thePhilippines. Her contribution led to the development of a package of technology on cottonproduction achieved in relatively short period of three years. She was also deeply involvedin the research on sunflower, which is a potential source of edible oil and livestock feed. Benjamin D. Cabrera. Most of Dr. Cabrera’s works are on medical parasitology andpublic health. Parasitology is concerned with parasitism and the parasites, like intestinalparasites, its causes and possible prevention. Because of his work on epidemiology and life cycle of filarial parasites, preventivemeasures through the development of drugs, can now be implemented on humansespecially against mosquito carriers. With the model he proposed, ascariasis or soil-transmitted helminthes can now be reduced. Eduardo A. Quisumbing is widely known in botany, especially for his work ontaxonomy, systematics and morphology. His researches on Philippine medicinal plants andorchids are pioneering. He is the author of Medicinal Plants of the Philippines, which isconsidered a forerunner on the subject in our country today. He has also written onehundred twenty-nine scientific articles. Francisco M. Fronda. Dr. Fronda’s most significant contribution is the developmentof poultry industry in the Philippines as well as in the Asian region. His title as the “Father ofPoultry Science in the Philippines” is but fitting to his share in the development of the poultryand livestock industry. He spent over six decades – virtually a lifetime – teaching, doingresearches and extension work, and he truly deserves the honor. - 15 -

Emerita V. de Guzman. The outstanding contribution of Dr. de Guzman is thedevelopment of the makapuno embryo inside a test tube (in vitro development). Thisdiscovery has dramatically changed the ratio of the makapuno-bearing nuts in the tropicswhich ranges only three to five makapuno nuts in every raceme or cluster of fourteen tonineteen nuts. Dr. de Guzman successfully produced one hundred per cent all makapuno-bearing nuts in a cluster. Emil Q. Javier. Dr.Javier has been known for his practical and realistic approachesto the problems confronting the small farmers, especially in a tropical and developingcountry like the Philippines. Keenly aware of the limited resources of the small farmers, Dr.Javier directed his researches towards developing practical methods to improve cropproduction using cheap, indigenous materials. Jovenito D. Soriano. Some of Dr. Soriano’s studies on plant cytogenetics (or thestudy dealing with the cells and their processes) and researches on mutations have beenpublished in international journals. He shed light on the understanding of the mutationprocess (mutation is the process of cell transformation or cell change). What you will do Activity 3.1 Calculating MagnificationObjects viewed under the microscope appear larger than their normal size because they aremagnified. Total magnification describes how much larger an object appears when viewedthrough the microscope.Learning the Skill:1. Look for a number marked with an X on the following: a. eyepiece b. objective The X stands for how many times the lens of the microscope magnifies an object.2. To calculate total magnification, multiply the number on the eyepiece by the number on the objective.Now try the following: a. If the eyepiece magnification is 5x, and the objective magnification is 10x, then the total magnification is? b. If the eyepiece magnification is 5x, and the objective magnification is 20x, then the total magnification is? - 16 -

What you will do Self-Test 3.1Use a separate sheet of paper to write down your answers.Free Response 1. What is a microscope? 2. What is a compound microscope? 3. What are the lenses on a microscope called? 4. How should a microscope be carried? 5. How is the total magnification of a microscope determined? 6. What is the purpose of the mirror and diaphragm? 7. What is the purpose of the adjustment knob? 8. What do the clips hold? 9. What is magnification? resolution? 10. Why may it be necessary to continually focus a microscope? Key to answers on page 21. Let’s Summarize 1. The basic characteristics of living things include movement, metabolism, growth, response, and reproduction. 2. Metabolism is the sum of all chemical activities essential to life. Ingestion, digestion, respiration, and excretion are metabolic activities that occur in all organisms. 3. Life span is the maximum length of time a particular organism can be expected to live. 4. A living thing reacts to a stimulus, which is a change in the environment, by producing a response. 5. Reproduction is the process by which organisms produce offspring. 6. Asexual reproduction requires only one parent while sexual reproduction requires two parents. 7. Living things need energy for metabolism. The primary source of energy for all living things is the sun. 8. Oxygen in the air or dissolved in water is used by all organisms during respiration. Carbon dioxide is used by plants to make food. 9. Homeostasis is the ability of an organism to keep conditions constant inside its body when the outside environment changes. - 17 -

10. Biotechnology is the application of technology to the study and solution of problems of living things.11. When DNA from one organism is removed and inserted into another organism, the new piece of DNA is known as recombinant DNA. The technique by which recombinant DNA is made is called genetic engineering.12. In genetic engineering, scientists remove a plasmid from a bacterium. Next a short piece of DNA is removed from another cell such as a human cell. The short piece of DNA is joined to the plasmid after it is opened. Then, the plasmid is returned to the bacterium.13. The products of recombinant DNA are used to produce vaccines, insulin, interferon, and human growth hormone.14. Genetic engineering is also used to protect plants from the tobacco mosaic virus and to prevent the development of frost on plants.15. Microscopes magnify small objects and produce enlarged images of them.16. Lasers and computers have important applications in life sciences.PosttestMultiple Choice. Choose the letter of the best answer. Write the chosen letter on aseparate sheet of paper.1. Which is NOT one of the basic characteristics of life?a. air c. metabolismb. response d. reproduction2. Life activities such as ingestion and digestion are parts of the process ofa. growth c. metabolismb. response d. respiration3. Organisms combine oxygen with other materials to produce energy duringa. digestion c. ingestionb. excretion d. respiration4. The maximum length of time an animal can be expected to live is itsa. growth c. developmentb. life span d. spontaneous generation5. A signal to which an organism reacts is called a (an)a. action c. stimulusb. response d. environment6. All organisms directly or indirectly obtain energy froma. plants c. the sunb. animals d. excretion - 18 -

7. The process by which complex foods are broken down into simple usable materials isa. digestion c. absorptionb. ingestion d. photosynthesis8. The distribution of digested materials and oxygen to all parts of the body and theremoval of wastes produced by normal body activities occur in the process ofa. excretion c. respirationb. circulation d. assimilation9. The life process in which certain chemicals are produced by an animal isa. digestion c. secretionb. excretion d. metabolism10. The life process involved with the elimination of waste products of an animal isa. digestion c. secretionb. excretion d. metabolism11. The study of the structure of organisms is calleda. anatomy c. physiologyb. ecology d. biochemistry12. A method used to separate DNA fragment isa. PCR c. DNA fingerprintingb. recombinant DNA d. gel electrophoresis13. The application of technology to the study and solution of problems involving living thingsis known asa. inbreeding c. biotechnologyb. hybridization d. genetic engineering14. In genetic engineering, the new pieces of combined DNA are calleda. inbreeding c. recombinant DNAb. hybridization d. selective breeding15. A plasmid is a (an) c. nitrogen base in DNA a. enzyme d. ring-like form of DNA b. growth hormone16. Which of the following has been genetically engineered to produce proteins made byother organisms?a. mice c. bacteriab. plants d. human beings17. Which of the following is NOT produced as a result of genetic engineering?a. insulin c. ice-minus bacteriab. square tomatoes d. human growth hormone - 19 -

18. A microscope with a 10x objective and a 50x occular magnifies a. 40 times c. 150 times b. 60 times d. 500 times19. A microscope that magnifies parts inside a cell three hundred thousand times or more isthe a. stereoscopic microscope c. scanning electron microscope b. compound light microscope d. transmission electronic microscope20. Which scientist found that cells are the basic units of function and structure of all livingthings? a. Hooke c. Leeuwenhoek b. Janssen d. Schleiden, Schwann, Virchow, et al. Key to answers on page 21. Key to AnswersPretest 6. a 11. d 16. b 7. c 12. a 17. a 1. b 8. a 13. c 18. d 2. d 9. a 14. d 19. c 3. d 10.a 15. b 20. c 4. c 5. a 6. b 11. i 16. l 7. c 12. h 17. jLesson 1 8. a 13. e 18. m 9. f 14. nSelf-Test 1.1 10. g 15. k 1. b 2. c 3. a 4. d 5. d - 20 -

Lesson 2Self-Test 2.1A. 1. d B. 1. negative 2. e 2. migration 3. b 3. splicing 4. c 4. biotechnology 5. a 5. restriction siteLesson 3Self-Test 3.11. A microscope is a tool used to study objects too small to be seen with the naked eye. The purpose of the microscope is to magnify small objects so that they can be seen.2. The compound microscope consists of two lenses, each fitted into the end of a tube within a tube.3. The two sets of lenses are called the eyepiece and the objective.4. A microscope should be carried with one hand under the base and one hand around the arm.5. The total magnification of a microscope can be determined by multiplying the magnification of the eyepiece and the magnification of the objective.6. The mirror bounces light up through the hole in the stage to the eye. Adjusting the diaphragm regulates light.7. The adjustment knob moves the body tube up and down.8. The clips hold the slide in place.9. Magnification is the enlarging of an image. Resolution is the scientific word for focusing to get a sharp image.10. It is necessary to re-focus a microscope in order to get a sharp picture. This is especially true when you are viewing living things because they move from one point to another.Posttest1. a 6. c 11. a 16. c2. c 7. a 12. d 17. b3. d 8. b 13. c 18. d4. b 9. c 14. c 19. d5. c 10. b 15. d 20. d - 21 -

ReferencesDaniel, L., Ortleb, E.P. & Biggs, A. (1994). Life science. New York: Glencoe.Goodman, H.D. & Stoltze, H.J. (1986). Biology. Florida: Harcourt Brace Jovanovich.Gottfried, S. & Emmel, T.C. (1986). Biology. New Jersey: Prentice-Hall.Kaskel, A., Hummer, P.J. Jr. & Daniel.L. (1992). Biology: An everyday experience. New York: Glencoe.Medley, D. (1998). Biology: Reviewing the essentials. New York: Amsco.Otto, J.H. & Towle, A. (1985). Modern biology. New York: Holt, Rinehart and Winston.Wong, H.K. & Dolmatz, M.S. (1983). Biology: The key ideas. New Jersey: Prentice-Hall.Wright, J. & Schraer, W.D. (1991). Life science. New Jersey: Prentice-Hall. - 22 -

Module 2 Cell Structure and Function What this module is about This module will help you gain knowledge about the cell: the basic unit of life onearth. Cells are the fundamental units of living organisms. The cell is the key to biologybecause it is at this level that life truly springs. As you read this, you will learn more aboutthe activities of the cell, the structures and the material of life that fills them. Later on, youwill discover what a living material is made of. This module has the following lessons:  Lesson 1 – Cell Theory  Lesson 2 – Cell: The Basis of Life  Lesson 3 – Cell Types What you are expected to learn After going through this module, you are expected to: 1. identify the different parts of the cell; 2. differentiate plant cells from animal cells; 3. differentiate unicellular organisms from multicellular organisms; 4. differentiate prokaryotic from eukaryotic cells; 5. state the cell theory; 6. appreciate the cell as a highly organized structure. How to learn from this module I know you are excited to start this adventure just as I am but remember to do thefollowing tips to successfully achieve the objectives of this self-learning kit. 1. Read the instructions carefully.

2. Follow the instructions carefully.3. Answer the pretest before you start the lesson.4. Take note and record points for clarifications.5. Try to achieve at least a 75% level of proficiency in the tests.6. Work diligently and honestly.7. Answer the posttest.What to do before (Pretest) To start off, you have to answer the pre-test for you to measure how much you know about the topic. You can start now.  There are 20 questions. Each question has ONLY ONE CORRECT ANSWER. Choose the one you believe to be best.  Each question is worth 2 points.  Read each question fully and carefully. Take your time.  GOOD LUCK!1. Where is the site of protein synthesis? c. ribosome a. nucleus d. mitochondria b. lysosome2. Organisms whose cells do not have a nucleus are calleda. plants c. eukaryotesb. organelles d. prokaryotes3. What type of cell has these characteristics: contains DNA but no nucleus, containsflagella, ribosomes, cytoplasm, and a cell membrane.a. plant c. animalb. fungi d. bacteria4. A cell with relatively few energy needs will probably have a relatively small number ofa. ribosomes c. mitochondriab. lysosomes d. chromosomes -2-

5. In which of the following items would you expect to find cells?a. strawberry c. silver dollarb. eyeglasses d. plastic flower6. Which of the following organelles transports materials inside the cella. lysosome c. mitochondriab. chloroplast d. endoplasmic reticulum7. Which of the following structures are common to both eukaryotic and prokaryotic cells?a. nucleus c. both b and cb. ribosomes d. cell membrane8. Which of the following forms of life is not eukaryotic?a. a bacterial cell c. a plant cell like gumamelab. protist such as an amoeba d. a human cell such as a red blood cell9. Plant cells often have a box-like shape because of thea. nucleus c. cytoplasmb. cell wall d. cell membrane10. Which organelle has no membrane? c. ribosome a. vacuole d. chloroplast b. lysosome11. Which of the following statements is always true?a. All cells have a cell wall. c. All cells contain a chloroplast.b. All cells contain a nucleus. d. All cells have a cell membrane.12. A cell is observed to contain a nucleus, mitochondria and chloroplasts. From thisinformation you can conclude that the cell is:a. a plant cell c. a bacterial cellb. an animal cell d. a prokaryotic cell13. Which of the following is found in the nucleus?a. vacuoles c. mitochondriab. chloroplasts d. chromosomes14. Digestive enzymes or hydrolytic enzymes are terms associated witha. ribosomes c. golgi apparatusb. lysosomes d. smooth endoplasmic reticulum15. What site regulates what goes in and out of the cell?a. cell wall c. cell membraneb. vacuole d. nuclear membrane -3-

16. The site of ATP production and the site of photosynthesis are the _______________ and_________________.a. ribosomes and vacuoles c. mitochondria and chloroplastb. chloroplast and lysosome d. Golgi complex and chloroplast17. Which is the “brain” of the cell? c. golgi bodies a. nucleus d. mitochondria b. chloroplast18. A cell that lacks a nucleus and membrane bound organelles is known as a(an)______________ cell.a. plant c. eukaryoteb. animal d. prokaryote19. What is the outermost boundary of an animal cell?a. the cell wall c. the cell membraneb. the cytoplasm d. the nuclear envelope20. Which of the following is not true of chloroplasts? a. They synthesize sugar b. They contain pigments c. They are only found in plants d. They appear green because of the chlorophyll Got a perfect score? Check it out! Key to answers on page 21.Lesson 1. Cell Theory The CELL THEORY, or cell doctrine, states that all organisms are composed ofsimilar units of organization, called cells. The concept was formally articulated in 1839 bySchleiden & Schwann and has remained as the foundation of modern biology. The ideapredates other great paradigms of biology including Darwin's theory of evolution (1859),Mendel's laws of inheritance (1865), and the establishment of comparative biochemistry(1940). Ultrastructural research and modern molecular biology have added many tenets to thecell theory, but it remains as the preeminent theory of biology. The Cell Theory is to Biologyas the Atomic Theory is to Physics. -4-

Figure 1.1 Red blood cells Source: fig.cox.Miami.edu/~cmallery/150/unity/cell.text.htmFormulation of the Cell Theory In 1838, Theodor Schwann and Matthias Schleiden were enjoying after-dinner coffeeand talking about their studies on cells. It has been suggested that when Schwann heardSchleiden describe plant cells with nuclei, he was struck by the similarity of these plant cellsto cells he had observed in animal tissues. The two scientists went immediately toSchwann's lab to look at his slides. Schwann published his book on animal and plant cells(Schwann 1839) the next year, a treatise lacking of acknowledgments of anyone else'scontribution, including that of Schleiden (1838). He summarized his observations into threeconclusions about cells: 1. The cell is the unit of structure, physiology, and organization in living things. 2. The cell retains a dual existence as a distinct entity and a building block in the construction of organisms. 3. Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation). We know today that the first two principles are correct, but the third is clearly wrong.The correct interpretation of cell formation by division was finally promoted by others andformally announced in Rudolph Virchow's powerful statement, \"Omnis cellula e cellula\"...\"All cells only arise from pre-existing cells\".The modern principles of the Cell Theory include the following: 1. All known living things are made up of cells. 2. The cell is the structural and functional unit of all living things. 3. All cells come from pre-existing cells by division. (Spontaneous generation does not occur). 4. Cells contain hereditary information which is passed from cell to cell during cell division. 5. All cells are basically the same in chemical composition. 6. All energy flow (metabolism and biochemistry) of life occurs within cells. -5-

Figure 1.2 Plant cells Source: fig.cox.Miami.edu/~cmallery/150/unity/cell.text.htmLandmarks in the Study of Cell Biology 1595 Jansen credited with first compound microscope 1626 Redi postulated that living things do not arise from spontaneous generation. 1655 Hooke described 'cells' in cork. 1674 Leeuwenhoek discovered protozoa. He saw bacteria some 9 years later. 1833 Brown descibed the cell nucleus in cells of the orchid. 1838 Schleiden and Schwann proposed cell theory. 1840 Albrecht von Roelliker realized that sperm cells and egg cells are also cells. 1856 N. Pringsheim observed how a sperm cell penetrated an egg cell. 1858 Rudolf Virchow (physician, pathologist and anthropologist) expounds his famous conclusion: omnis cellula e cellula, that is cells develop only from existing cells [cells come from preexisting cells] 1857 Kolliker described mitochondria. 1869 Miescher isolated DNA for the first time. 1879 Flemming described chromosome behavior during mitosis. 1883 Germ cells are haploid, chromosome theory of heredity. 1898 Golgi described the golgi apparatus. 1926 Svedberg developed the first analytical ultracentrifuge. 1938 Behrens used differential centrifugation to separate nuclei from cytoplasm. 1939 Siemens produced the first commercial transmission electron microscope. -6-

1941 Coons used fluorescent labeled antibodies to detect cellular antigens.1952 Gey and co-workers established a continuous human cell line.1953 Crick, Wilkins and Watson proposed structure of DNA double-helix.1955 Eagle systematically defined the nutritional needs of animal cells in culture.1957 Meselson, Stahl and Vinograd developed density gradient centrifugation in cesium chloride solutions for separating nucleic acids.1965 Ham introduced a defined serum-free medium. Cambridge Instruments produced the first commercial scanning electron microscope.1976 Sato and colleagues publish papers showing that different cell lines require different mixtures of hormones and growth factors in serum-free media.1981 Transgenic mice and fruit flies are produced. Mouse embryonic stem cell line established.1987 Creation of first knockout mouse which contains an artificially introduced mutation in their cells.1998 Mice are cloned from somatic cells.2000 Human genome DNA sequence draft Figure 1.3 Cork cells and the early microscope Source: fig.cox.miami.edu/~cmallery/150/unity/cell.text.htm Prior to 1931 when the first electron microscope was developed, magnification ofmicroscopes was limited to about 2 000 times. The small cell structures did not show upwell or remained invisible. The electron microscope not only showed more detail of -7-

previously known parts of the cell but also revealed new parts. Cells and cell structures cannow be examined at magnifications of up to 500 000 times and more. What you will do Activity 1.1 The Street Sweepers The air we breathe is filled with dust, smoke, and even small bacteria. How come all these materials do not accumulate in the lungs and clog their passageways? Key to answers on page 21. What you will do Self-Test 1.1Answer the following questions briefly.1. What contributions did van Leeuwenhoek, Hooke, Schleiden, Schwann, and Virchow make to the development of the cell theory? ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________2. What role did the invention of the microscope play in the development of the cell theory? ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ Key to answers on page 21. -8-

Lesson 2. Cell: The Basis of Life Have you tried to look closely at something? You may have picked up a coin andlooked closely at its surface. You may also have examined the face of a stamp or looked ata blade of grass. Such curiosity led early investigators to examine living things in the hope of getting abetter view of their structure. Little by little, they discovered that all living things are made ofcells. Cells are the basic units of structure and function in living things. All organisms suchas the birds you watch, the cork trees and so on are made of living cells. Figure 2.1 Living things Source: www.goofyanimals.com/pictures FIND OUT! Break a chicken egg into a dish, and look at the yolk. How large do you think is it? Estimate its width. Then use a metric ruler to measure the width of your chicken yolk cell. With a hand lens, observe the yolk closely. Other cells that can be seen easily are large fish eggs.Most cells are too small to be seen without the help of a microscope. Luckily, there are afew cells that can be seen with your naked eyes.Cells Have Structures Imagine that you could become smaller, down to the size of one micron (1 micron =1/1000 inch). Your whole body would be smaller than the typical animal cell (see figure2.2). Imagine, that you could step inside this cell and explore it. Find out some structuresinside a cell. Be able to explore how bacterial cells are different from other cells such asplant and animal cells. -9-

cytoplasm Figure 2.2 An animal cell Source: http://www.cellsalive.com/cells/animcell.htm While cells differ in size and shape, most of them have common structures. The cellsof animals, plants, and related organisms have three basic structures:  Cell membrane – the outer boundary of the cell.  Nucleus – the control center of the cell.  Cytoplasm – the material between the cell membrane and the nucleus. The first thing you see as you approach this cell is a thin sac-like membrane. Thecell membrane covers the entire surface of the cell. As you take the imaginary step throughthe cell membrane, you immediately come in contact with the cytoplasm. Moving throughthe cytoplasm would be like moving through a jar of jelly. What you will do Activity 2.1 Construct This MINI-Lab (What a cytoplasm is like) Make a model of cytoplasm. Fill a jar/wide-mouthed bottle with water. Add unflavored gulaman and stir. Shine a flashlight through the beaker. What do you see? How does a model cell help you understand what a real one is like? - 10 -

A large, round nucleus is found somewhere in the cytoplasm. As the “control center”of the cell, the nucleus contains coded instructions for all of the cell’s activities. Thesecoded instructions are stored on special structures called the chromosomes.Chromosomes are seen when a cell is reproducing. Just as the cell membrane covers the cell, a nuclear membrane covers the nucleusof the cell. It regulates the passage of materials in and out of the nucleus.Cytoplasmic Structures As you walk through the cytoplasm, you might bump into sausage-shaped bodiescalled mitochondria. They are commonly called the “power houses” of the cell. They trapthe energy that results when food is broken down. Just as a power plant supplies energy toa business, mitochondria provide energy for the cell. Some types of cells are more activethan others, that’s why they can have more mitochondria. Analyze This Why might a muscle cell have more mitochondria than other cells?Muscle cells are always undergoing some type of movement. Muscles are also the onesexposed to strenuous activities like doing some household chores, running, walking, etc. Ever since you entered the cell, you have been walking on a network of canals calledthe endoplasmic reticulum. The endoplasmic reticulum extends from the nucleus to thecell membrane and takes up quite a lot of space in some cells. It moves material from oneplace to another place inside the cell. Ribosomes are the tiny dots you see on the edges of some of the endoplasmicreticulum. Some cells may contain millions of ribosomes. The actual building blocks of thecell (proteins) are made on the surfaces of these very tiny structures. In a manufacturing business, products are made, packaged, and moved to loadingcenters to be carried away. Structures called golgi bodies are the packaging and releasingstructures of the cell. When something is released, it is given off by the cell. Applying a Concept An animal cell contains about 10 to 20 golgi bodies, while a plant cell contains several hundreds. Why do you think there is such a difference in the number of these structures in each cell type? - 11 -

Compare your answer to this: The fact that plants produce so many materials (food, oils,resins, etc.), they will be in need of more golgi bodies to store the said materials. Do you know that cells also produce wastes? In the cytoplasm, structures calledlysosomes contain chemicals that digest wastes and worn-out/damaged cell parts. When acell dies, chemicals in the lysosomes act to quickly break down the cell. In a healthy cell, themembrane around the lysosome keeps it from breaking down the cell itself. Plant cells donot have lysosomes. Many businesses have warehouses for storing products until they are sold.Vacuoles are storage areas in cells. They may store water, food, or waste products. Inplant cells, vacuoles are big. In animal cells, vacuoles are small. Why do you think so?Feedback: Plants are said to be the producers of food in the environment. They mayproduce sugar, oil, nectar, etc. They are in need of bigger vacuoles to store such materials. You have just looked at the inner workings of an animal cell. Imagine now that youare taking a microscopic tour through the green plant cell below. You will find that somestructures in this cell are quite different from the structures in an animal cell. Take note ofthem. Figure 2.3 A plant cell Source: http://www.cellsalive.com/cells/plantcell.htm - 12 -

The outer covering of the plant cell is not soft and thin. Instead, it is surrounded by arigid/tough structure called the cell wall that supports and protects the plant cell. Once you pass through the cell wall, you see the same structures you saw in theanimal cell. Hold on! Something new appears. The dark green bodies you see around you arechloroplasts. Substances inside the chloroplast help a green plant cell trap the sun’senergy and then produce food. Imagine you could take a trip into a tiny bacterial cell. Bacteria and blue-bacteria arequite different from other cells. They have fewer structures than plant or animal cells.However, they carry out all of the life processes that other cells carry out. You can see thata bacterium has a cell wall, a cell membrane, and cytoplasm. The chromosome material(nucleoid), which directs the cell’s activities, floats freely through the cytoplasm. The otherstructures are lacking. Figure 2.4 A bacterial cell Source: http//www.cellsalive.com/cells/bactcell.htm Remember Cells need water to maintain health. Turning off the faucet every time you brush your teeth can conserve as much as five gallons of water. It will surely benefit a living organism somewhere! - 13 -

What you will doActivity 2.2 Challenge Make your own model of a cell at home. Prepare a small package of gulaman and pour it into a dish. Put common foods in the gelatin to represent cell structures. You could use lettuce or shredded carrots for endoplasmic reticulum and raisins for mitochondria. Be creative! Unmold your “cell”. And serve it to your family for salad or dessert.What you will doSelf-Test 2.1 Let us see how well you can make a summary of what you know about the cell.Below is a table that lists the names of the cell structure(s). Now, compare animal, plantand bacterial cells by putting a (/) if the structure is present and an (X) if the structure isabsent under each column. Structures Animal cell Plant cell Bacterial cell1. Cell wall2. Cell membrane3. Cytoplasm4. Mitochondria5. Ribosomes6. Endoplasmic reticulum7. Golgi bodies8. Lysosomes9. Vacuoles10. Chloroplasts11. Nucleus12. Chromosomes Key to answers on page 22.Perfect?! If yes, fantastic! If not, just try and try again. Remember, no pain, no gain. - 14 -

What you will do Self-Test 2.2 A Tale of a Tail Mrs. Gonzales' class studied the parts of plant and animal cells. The class capturedtiny tadpoles in a local stream. Mrs. Gonzales showed the students how to care for thetadpoles in the classroom. Gradually, as the animals grew, the bodies were changing inshape. Back and front legs grew out. The mouth expanded from a small hole to a largeopening capable of swallowing large insects. In addition, the tails started to disappear. Mrs.Gonzales told the whole class that there would be a bonus question about the tadpoles inthe test on animals. For a study clue, she told them to review their notes on cells. What dochanges in the body parts of the tadpoles have to do with cells?Think critically: Answer the bonus question:What cell part makes the tadpole tails disappear? How? Figure 2.5 Tadpoles Source: http://www.sciencedaily.com/encyclopedia/tadpole Key to answers on page 22.Ooops! Take a deep breath. Relax for a while. What?! You want to move on? All right,your wish is granted! You may continue. Are you enjoying the module? I hope so. If yes,well and good! Hold on! We will now take the path to the next lesson. Keep on having funas you learn!Lesson 3. Cell TypesCells Vary in Shape, Size, and Arrangement Just as there is variety among organisms, there is also variety among cells. Your own body contains over a hundred different kinds of cells. Some of these cells are round. Others are shaped like long, tangled strings. - 15 -

 Cells vary greatly in size, too. The bacteria that naturally live deep inside your body are very tiny. The ostrich egg cell below is 800,000 times bigger than the bacterial cells. Ostrich egg cell The living arrangement of cells also varies. The bacteria and other cells you might find in a drop of pond water live by themselves. These cells are one-celled organisms. You, your classmates, the cork trees and a variety of other organisms are many-celled organisms. Now that we’ve learned all about cells and their contents, it’s time to learn how cellsare categorized. The first grouping is Prokaryotes and Eukaryotes. These are hard topronounce Latin words, but their meanings are simple. Prokaryote refers to bacterial cells.Eukaryote refers to everything else. So, streptomyocin bacteria are prokaryote cells.Animals, plants and fungi (mushrooms) are made of eukaryote cells. Figure 3.1 Eukaryotic organisms Source: http://userpages.umbc.edu/~lruppi/project1index.shtml What are the differences between these cell types? A major difference between thetwo is the presence of membrane-bound organelles. Inside these cells we get things likemitochondria, golgi bodies, a nucleus, etc. They are clearly defined because they haveinternal membranes around them. The membranes hold them together. Prokaryote lacksthese membranes, so consequently they don’t have these organelles. Instead of a clearlydefined nucleus with chromosomes, they have a single, circular piece of DNA. Thus,prokaryotes are simple and smaller than eukaryotes. What do they have in common? Well, while the prokaryotes do not have internalmembranes, they do have a cell membrane just like the eukaryotes. They are also filledwith cytoplasm. Finally, they have organelles which do not require membranes, (e.g.ribosomes). Imagine you could take a trip into a tiny bacterial cell. Bacteria and blue-bacteria arequite different from other cells. They have fewer structures than plant or animal cells.However, they carry out all of the life processes that other cells carry out. You can see thata bacteria has a cell wall, a cell membrane, and cytoplasm. The chromosome material,which directs the cell’s activities, floats freely through the cytoplasm. The other structuresare lacking. - 16 -

A single-celled bacteria: The one-celled organism A human red blood cell E. coli Amoeba proteus Figure 3.2 Some cell types. Source: http://web.jjay.cuny.edu/~acarpi/NSC/13-cell.htm The second cell grouping is Plants versus Animal cells. Both of these cell types areeukaryotes. This means they have a lot of organelles in common. One organelle they don’thave in common is chloroplasts, which only plants have. Another organelle difference is thevacuoles. In animal cells the vacuoles are small and plenty. In the plant cells, there is alarge central vacuole that occupies over 50% of the plant cell’s volume. This vacuole isfilled with water and nutrients under pressure. The pressure helps maintain the plant cell’srigid shape. The rigid shape results in plant cells looking rectangular as compared to the round-like animal cells. While both cell types have cell membranes, the plant cell’s rigidity isfurther maintained by an additional cell wall outside the membrane. What you will do Activity 3.1Read, Think and WriteOne day one-celled organisms got Blah! Blah! Blah! Blah! Blah! Blah! Blah! Blah!tired of being called simpleorganisms by the many-celledorganisms. The one-celledorganisms felt that they were rathercomplex individuals and should berecognized as such. In order togain this recognition, theychallenged the many-celledorganisms to a debate. Pretendthat you are a one-celled organism.What arguments would you use todefend your position? Write them Key to answers on page 22.down. - 17 -

What you will do Self-Test 3.1Answer the following questions:1. Chloroplasts are found in which type of cell?2. What do you call the broad group of cells that lack membrane bounded organelles?3. What type of cell (prokaryote or eukaryote) has DNA that floats freely in the cell?4. Mushroom is a unicellular organism. (True or false)5. Human is a multicellular organism. (True or false) Key to answers on page 22. Let’s Summarize 1. Cells are amazing, variable, beautiful, and functionally superb. A concept of genius, they work alone or in groups with equal ease. 2. Cells are the basic units of life. All living things are made up of one or more cells. Organisms that exist as single cells are called unicellular and organisms that are made up of groups of cells working together are called multicellular. 3. Because all living things are made up of cells, and because we desire to understand ourselves and the other living things around us it makes sense to learn something about cells. 4. All living things are divided into two major groups depending on how their cells are set up. These two groups are the Prokaryotes and the Eukaryotes. 5. The basic structure of plant and animal cell is almost the same except for certain differences. The basic structure of a cell is composed of the following components. a. Cell Membrane b. Cytoplasm c. Nucleus However in plants, a rigid \"Cell wall\" is present outside the cell membrane or plasma membrane. 6. Cell Theory: All living things are composed of cells. Cells are the basic units of structure and function in living things. All cells come from preexisting cells. - 18 -

Whew! At last! You have finished studying the module. But, before you completelyexit from this module, let us find out how much you learned from this material.PosttestMultiple Choice. Choose the letter of the best answer. Write the chosen letter on aseparate sheet of paper.1. Which of the following is NOT true of chloroplasts? a. They synthesize sugar b. They contain pigments c. They are only found in plants d. They appear green because of the chlorophyll2. Which of the following organelles transports materials inside the cella. lysosome c. mitochondriab. chloroplast d. endoplasmic reticulum3. Which of the following is found in the nucleus?a. vacuoles c. mitochondriab. chloroplasts d. chromosomes4. What type of cell has these characteristics: contains DNA but no nucleus, containsflagella, ribosomes, cytoplasm, and a cell membrane.a. plant c. animalb. fungi d. bacteria5. What site regulates what goes in and out of the cell?a. cell wall c. cell membraneb. vacuole d. nuclear membrane6. Digestive enzymes or hydrolytic enzymes are terms associated witha. ribosomes c. golgi apparatusb. lysosomes d. smooth endoplasmic reticulum7. In which of the following items would you expect to find cells?a. strawberry c. silver dollarb. eyeglasses d. plastic flower8. Where is the site of protein synthesis? c. ribosome a. nucleus d. mitochondria b. lysosome - 19 -

9. A cell with relatively few energy needs will probably have a relatively small number ofa. ribosomes c. mitochondriab. lysosomes d. chromosomes10. Organisms whose cells do not have a nucleus are calleda. plants c. eukaryotesb. organelles d. prokaryotes11. Which of the following structures are common to both eukaryotic and prokaryotic cells?a. nucleus c. both b and cb. ribosomes12. A cell is observed to contain a nucleus, mitochondria and chloroplasts. From thisinformation you can conclude that the cell is:a. a plant cell c. a bacterial cellb. an animal cell d. a prokaryotic cell13. Which of the following statements is always true?a. All cells have a cell wall. c. All cells contain a chloroplast.b. All cells contain a nucleus. d. All cells have a cell membrane.14. Plant cells often have a box-like shape because of thea. nucleus c. cytoplasmb. cell wall d. cell membrane15. Which is the “brain” of the cell? c. golgi bodies a. nucleus d. mitochondria b. chloroplast16. The site of ATP production and the site of photosynthesis are the _______________ and_________________.a. ribosomes and vacuoles c. mitochondria and chloroplastb. chloroplast and lysosome d. Golgi complex and chloroplast17. Which of the following forms of life is NOT eukaryotic?a. a bacterial cell c. a plant cell like gumamelab. protist such as an amoeba d. a human cell such as a red blood cell18. A cell that lacks a nucleus and membrane bound organelles is known as a(an)______________ cell.a. plant c. eukaryoteb. animal d. prokaryote19. Which organelle has no membrane? c. ribosome a. vacuole d. chloroplast b. lysosome - 20 -

20. What is the outermost boundary of an animal cell?a. the cell wall c. the cell membraneb. the cytoplasm d. the nuclear envelope Got a perfect score? Check it out! Key to answers on page 23. Key to AnswersPretest1. c 6. d 11. d 16. c2. d 7. b 12. a 17. a3. d 8. a 13. d 18. d4. c 9. b 14. b 19. c5. a 10. c 15. c 20. cLesson 1Activity 1.1 The Street SweepersLining the passageways are special cells that release a mixture of water,carbohydrates, and salts, called mucus. The particles of dust and dirt that areinhaled are trapped in this sticky mucus. Underneath this layer of mucus is anothergroup of specialized cells that have cilia. As the cilia move, they create a sweepingaction. This action keeps the most vital passageways in the body clean and open forbusiness.Self-Test 1.11. Leeuwenhoek: discovered protozoa Hooke: described “cells” in cork Schleiden & Schwann: proposed cell theory Virchow: concluded that cells come from preexisting cells2. The microscope opened up the world of the very small to biologists. It enabled scientists to discover that all living things are made up of cells. - 21 -

Lesson 2Self-Test 2.1 Cell Structures: A Summary Structures Animal cell Plant cell Bacterial cell1. Cell wall /2. Cell membrane X/ /3. Cytoplasm /4. Mitochondria // X5. Ribosomes /6. Endoplasmic // X reticulum //7. Golgi bodies X8. Lysosomes // X9. Vacuoles X10. Chloroplasts // X11. Nucleus X12. Chromosomes // / /X // X/ // //Self-Test 2.2The body parts of the tadpoles change in response to the activity of the cells which iscell division. When cells divide, their number increases. Growth results when cellsincrease in number.The tails of the tadpole disappear due to the lysosomal activity. The lysosome, if youwill recall, contains powerful chemicals which are used to digest or breakdownmaterialsLesson 3Activity 3.1Feedback: One-celled organisms may have fewer or different structures from plantor animal cells. However, they carry out all of the life processes (reproduction,digestion, excretion, respiration, etc.) that other cells carry out.Self-Test 3.11. plant2. prokaryote3. prokaryote4. false5. true - 22 -

Posttest 6. b 11. b 16. c 7. a 12. a 17. a 1. c 8. c 13. d 18. d 2. d 9. c 14. b 19. c 3. d 10. d 15. a 20. c 4. b 5. cReferencesBooks:Alexander, G.; Balzer, L.; Collins, A.; Goodson, P.; Lauer, L.; Slesnick, I. (1984). Introduction to biology. Glenview, Illinois: Scott Foresman And Company.Biggs, A.; Daniel, L.; Ortleb, P. (1994). Life science. Westerville, OH: Merrill Publishing Co., Mcmillan/McGraw-Hill.Campbell, N.A. (1996). Biology. California: The Benjamin/Cummings Publishing Company.Miller, K.R. & Levine, J. (1991). Biology. New Jersey, Massachusetts: Prentice Hall.Hopson, J.L. & Wessells, N.K. (1990). Essentials of biology. USA: McGraw-Hill Publishing Company.Wong, H.K. & Dolmatz, M.S. (1986). Biology: The key ideas. New York, NY: Globe Book Company, Inc.Electronic Sources:Retrieved November 26, 2004 from http://www.cellsalive.com/cells/bactcell.htmRetrieved November 26, 2004 from http://webjjay.cuny.edu/~acarpi/NSC/13-cell.htmRetrieved November 26, 2004 from http://koning.ecsu.ctstateu.edu/Plants_Human/ unitlife.htmlRetrieved November 26, 2004 from http:www.sciencedaily.com/encyclopedia/TadpoleRetrieved November 26, 2004 from http://userpages.umbc.edu/~lruppi/project1index.shtmlRetrieved December 21, 2004 from fig.cox.miami.edu/~cmallery/150/unity/cell.text.htm - 23 -

Module 3 Movement of Materials Through the Cell Membrane What this module is about Have you tried washing the dishes or staying in a pool so long that your fingersbecame wrinkled? What caused your fingers to wrinkle? How long did it take your fingersto return to normal? Why does this happen? In this lesson, you will learn how materials move into and out of the cells. You willalso learn how materials are constantly being exchanged between a living cell and the non-living world. You will also learn how discoveries on cellular structures and functions haveled to useful technologies. This module has the following lessons:  Lesson 1 – Substance Transport Across the Membrane  Lesson 2 – Passive Transport versus Active transport  Lesson 3 – Useful Technologies on Cellular Structures and Functions What you are expected to learn After going through this module, you are expected to: 1. discuss cellular exchange of materials with the environment; 2. explain osmosis as a type of diffusion; 3. distinguish between active and passive transport; 4. appreciate how discoveries on cellular structures and functions have led to useful technologies; and 5. explain how the activities of certain cell organelles are used to promote food production and health.

How to learn from this module I know you are excited to start the adventure just as I am but remember to do thefollowing tips to successfully achieve the objectives of this self-learning kit. 1. Read the instructions carefully. 2. Follow the instructions carefully. 3. Answer the pretest before you start the lesson. 4. Take note and record points for clarifications. 5. Try to achieve at least a 75% level of proficiency in the tests. 6. Work diligently and honestly. 7. Answer the posttest.What to do before (Pretest) Answer the pre-test to measure how much you know about the topic. You can start now.  There are 20 questions. Each question has ONLY ONE CORRECT ANSWER. Choose the one you believe to be best.  Each question is worth 2 points.  Read each question. Take your time.  GOOD LUCK!1. Which of the following molecules can penetrate rapidly across the cell membrane?a. H2O c. sugarb. Na+ d. protein2. Proteins enter and exit the cell by c. phagocytosis c. diffusion d. facilitated diffusion d. osmosis -2-

Use the diagram to answer questions 3 and 4. Outside CellCell Opening Inside Cell Cell Membrane = Water = Sugar3. What happens with the water molecules? a. The water molecules will enter the cell. b. The water molecules will move out of the cell. c. The water molecules will remain where they are.4. What happens with the sugar molecules? a. The sugar molecules will enter the cell. b. The sugar molecules will move out of the cell. c. The sugar molecules will remain where they are.5. Through which process do sugar molecules enter or exit a cell?a. diffusion c. facilitated diffusionb. osmosis d. none of the above6. Which process ALWAYS involves movement of materials from inside the cell to outsidethe cell?a. osmosis c. exocytosisb. diffusion d. endocytosis7. A substance that moves across a cell membrane without using the cell’s energy tends to move a. toward the area where it is more concentrated. b. away from the area where it is less concentrated. c. away from the area where it is more concentrated.8. If a solution outside a cell is more concentrated so that the cell loses water to itsenvironment, which of the following describes the external solution?a. isotonic c. hypertonicb. hypotonic d. in equilibrium -3-

9. Which mechanism requires energy? c. active transport a. osmosis d. facilitated diffusion b. diffusion10. Certain types of lymphocytes (white blood cells) in the lymph nodes ingest bacteria anddebris. This function most likely occurs bya. exocytosis d. passive transportb. pinocytosis e. facilitated transportc. phagocytosis11. Which of the following is characteristic of cell membrane?a. permeable c. semi permeableb. impermeable d. none of these12. Which refers to a solution containing a greater concentration of solvent than the solutionit is being compared with?a. isotonic c. hypertonicb. hypotonic d. equilibrium13. Which solution contains a higher concentration of solute than the solution it is beingcompared with?a. isotonic c. hypertonicb. hypotonic d. equilibrium14. What part of the cell maintains homeostasis in the cell?a. cell membrane c. Golgi bodiesb. mitochondria d. ribosomes15. What are the current benefits of having foods made from genetically modified crops? a. They improve farm profitability and make some farmers' jobs easier. b. They allow farmers to greatly increase the amount of crops produced. c. They improve convenience for consumers, e.g. by creating foods with longer shelf lives d. They improve the nutritional quality of foods. e. They cause less damage to the environment than conventional chemical intensive agriculture.16. What effect does eating genetically modified foods have on your genes? a. It has no effect on your genes. b. It could cause your own genes to mutate. c. The effects on human genetics are not known. d. It could cause your own genes to absorb the excess genes. -4-