9B01_The Fundamental Unit of Life_Avanti Module

9B01 – The Fundamental Unit of Life 1 Fifth Edition 9B01. The Fundamental Unit of Life TABLE OF CONTENTS 9B01. The Fundamental Unit of Life 1 9B01.1 Introduction to the Cell...........................................................................................................................................................2 9B01.2 Cell Wall, Cytoplasm and Nucleus......................................................................................................................................3 9B01.3 Cell Organelles ............................................................................................................................................................................5 Objective Assignment...............................................................................................................................................................................7 Olympiad Practice Problems..............................................................................................................................................................10

9B01 – The Fundamental Unit of Life 2 9B01.1 Introduction to the Cell CONCEPTS COVERED 1. Discovery of cell and its parts 2. Cell theory 3. Three main features of the cell 4. Plasma membrane and its role 5. Diffusion 6. Osmosis and its effect on cells under different environmental conditions IN CLASS EXERCISE Q1. Name the scientist who first studied living cell. Q2. What is the functional unit of life? Name the scientist who discovered it. How did he discover it? Q3. Who proposed the cell theory? What does it say? Q4. What is the plasma membrane and what are its constituents? Q5. Why is plasma membrane called a ‘selectively permeable membrane’? Q6. Define diffusion. Q7. What is osmosis? Q8. What is active transport? Q9. What is endocytosis? Explain with an example. Q10. Explain why it is not enough just to say that a solution is ‘hypertonic’. Q11. What will happen when I. An egg without shell is placed in concentrated salt solution for 5 minutes. Give reason in brief. II. An egg without shell is placed in pure/ distilled water for 5 minutes. Give reason in brief. HOMEWORK Q1. What are the three main features of a cell? Q2. Why did Robert Hooke name the functional unit of life as 'cell'? Q3. What is the difference between protoplasm and cytoplasm? Q4. What is the main function of plasma membrane? Q5. What do we mean by unicellular and multicellular? Q6. What are the different kinds of membranes, with respect to permeability? Q7. How do substances like ������������������������2 and water move in and out of the cell? Q8. Define I. Hypertonic solution; II. Hypotonic solution III. Isotonic solution Q9. What is division of labour? Explain it in context of multicellular organisms. Q10. Differentiate between diffusion and osmosis with examples. Q11. Differentiate between optical and electron microscope. 9B01.1

9B01 – The Fundamental Unit of Life 3 9B01.2 Cell Wall, Cytoplasm and Nucleus CONCEPTS COVERED 1. Cell wall and its role 2. Plasmolysis 3. Cytoplasm and its role 4. Nucleus, parts of the nucleus, and its role 5. Eukaryotic and prokaryotic cells 6. Introduction to cell organelles 7. Smooth and rough endoplasmic reticulum and their role 8. Ribosome and its role IN CLASS EXERCISE Q1. Which cell type probably evolved first? Q2. Where are proteins synthesized in our cells? Q3. Why is the nucleus called the 'director of cell'? Q4. What is the cell wall? Comment on its permeability. Q5. For each of the following situations, state whether we can observe plasmolysis. Give reasons for your answers. I. Freshly obtained leaves kept in concentrated sugar solution II. Freshly obtained leaves kept in distilled water III. Boiled leaves kept in concentrated sugar solution IV. Boiled leaves kept in distilled water V. Freshly collected cheek cell sample, kept in concentrated sugar solution VI. Freshly collected cheek cell sample, kept in distilled water Q6. What is cytoplasm? Q7. Define the following: I. Chromosome II. Chromatin material III. DNA IV. Gene Q8. What is the difference between the cytoplasmic content of a prokaryotic and eukaryotic cell? Q9. List two functions of chromosomes. Q10. How is the nucleoid region of a prokaryotic cell unlike the nucleus of a eukaryotic cell? Q11. Cells of plants, fungi and bacteria can withstand much greater changes in the surrounding medium than animal cells. Explain. Q12. What is endoplasmic reticulum? Describe its structure with a neat diagram. Q13. What are the two types of endoplasmic reticulum? Differentiate between the two. Q14. What is the significance of membranes for a cell? How is the presence of organelles within eukaryotes significant for their higher complexity and diversity as compared to prokaryotes? 9B01.2

9B01 – The Fundamental Unit of Life 4 HOMEWORK Q1. Give one word answers for the following: I. Organisms whose cells lack a nuclear membrane II. Entire fluid content of the cell, other than the nucleus, enclosed by the plasma membrane III. Functional segment of DNA IV. Rod-shaped structures present in nucleus visible during cell division V. Entangled mass of thread-like structures present in nucleus Q2. What method should we use if we need to identify a nucleus under a microscope? Q3. What is DNA? Why is it important? Q4. What is nucleoid? Q5. What is an organelle? Q6. What is nuclear membrane? Q7. What is the difference between plasma membrane and cell wall? Explain giving functions of each. Q8. What is cell wall? What are its constituents in different types of cells? Q9. What is membrane biogenesis? Q10. What is plasmolysis? Explain with diagrams. Q11. What role does nucleus play in cellular reproduction? Q12. How are cells differentiated on the basis of presence and absence of nuclear membrane? Q13. Draw a neat labelled diagram of a prokaryotic cell. Q14. What is the function of endoplasmic reticulum? 9B01.3

9B01 – The Fundamental Unit of Life 5 9B01.3 Cell Organelles CONCEPTS COVERED 1. Golgi apparatus and its role 2. Lysosomes and its role 3. Mitochondria and its role 4. Plastids, their types and role 5. Vacuoles and their role 6. Differences in plant and animal cell IN CLASS EXERCISE Q1. Name the two cell organelles that contain their own genetic material (in addition to the nucleus)? Q2. What is mitochondria? Q3. What is a cistern? Q4. Why are lysosomes known as 'suicide bags'? Q5. Expand the term ATP. What is its function? Q6. What is ‘stroma’? Where is it present inside the cell? Q7. What are plastids? Name the plastid which stores starch, oils and protein granules. Q8. What are vacuoles? Q9. What would happen if the Golgi apparatus did not exist in a cell? Q10. Bacteria do not have chloroplast, but some bacteria are photoautotrophic in nature and perform photosynthesis. How do these cells do this? Q11. Describe the structure of mitochondria with the help of a neat labeled diagram. Q12. Draw a neat labelled diagram of plant cell. Q13. Solve the crossword puzzle below using the given clues: Across 1. Type of solution which will make the cell shrink if the cell is surrounded by it 4. Entangled thread-like mass in the nucleus 6. Energy currency of the cell 9. Number of layers in nuclear membrane 10. Suicide bags of the cell 12. Discoverer of cell, Robert __________ 13. Type of cells that don't have a nucleus 14. Non-cellular microbes Down 2. Spheres embedded on the surface of endoplasmic reticulum, making it rough 3. Amoeba acquires its food through a process called __________ 5. Cellular storage sacs 7. Green organelles found only in plant cells 8. Plant cell wall is made of _________ 11. Movement of water molecules across a semi-permeable membrane 9B01.3

9B01 – The Fundamental Unit of Life 6 HOMEWORK Q1. Give one word answer for the following: I. __________ is called the energy currency of the cell. II. _________ are important for photosynthesis in plants III. Coloured plastids are called __________, while white or colourless plastids are called __________ IV. The internal organisation of the plastids consists of numerous membrane layers embedded in a material called __________. Q2. You have learnt about the active and passive transport mechanisms occurring in the cell. What is the energy source for active transport? Q3. What are lysosomes? Q4. What are chromoplasts and leucoplasts? Which chromoplast has a green pigment? Q5. Which organelle is known as the powerhouse of the cell? Why? Q6. Give scientific reason for the following: I. Inner membrane of mitochondria is deeply folded II. Mitochondria are able to make some of their own proteins III. Golgi apparatus is also called the 'secretory organelle of the cell' Q7. I. Name the organelle which provides turgidity and rigidity to the plant cell. Name any two substances which are present in it. II. How are they useful in unicellular organisms? Q8. Why do plant cells have more and larger vacuoles, as compared to the animal cell? Q9. What is the difference between a plant cell and an animal cell? Q10. If the organization of a cell is destroyed due to some physical or chemical influence, what will happen to the cell? Q11. What types of enzymes are present in the lysosomes and what is their function? Q12. Draw a neat labelled diagram of animal cell. Q13. Draw and briefly explain the structure of Golgi apparatus. 9B01.3

7 9B01 – Fundamental Unit of Life – CBSE Practice Problems INSTRUCTIONS Answer each of the following questions. 1. Which of the following can be made into crystals? B) An Amoeba D) A Sperm A) A Bacteriun C) A virus 2. Chromosomes are made up of B) Protein D) RNA A) DNA C) DNA and Protein 3. Colourless plastids are known as B) Chloroplasts D) Protoplast A) Chromoplasts C) Leucoplasts 4. The barrier between the protoplasm and the outer environment in an animal cell is A) Cell wall B) Plasma Membrane C) Nuclear Membrane D) Cytoplasm 5. Which is the largest cell organelle present in plant cell? B) Chloroplast D) Mitochondria A) Nucleus C) Endoplasmic Reticulum 6. Which of the following are the main constituents of cell wall? A) Cellulose B) Pectin C) Starch D) Protein D) Lysosome 7. Root hair absorbs water from soil through D) Kidney cell D) Eukaryotes A) Osmosis B) Active transport C) Diffusion D) Endocytosis D) 1 8. Double membrane is absent in A) Mitochondria B) Chloroplast C) Nucleus 9. The longest cell in the human body is A) Nerve cell B) Muscle cell C) Liver cell 10. A plant cell differs from an animal cell in the absence of: B) Mitochondria D) Centriole A) Endoplasmic Reticulun C) Ribosome 11. Organisms Lacking nucleus and membrane bound organelle are: A) Diploids B) Prokaryotes C) Haploids 12. Cell secretion is done by:- B) Endoplasmic reticulum D) Nucleolus A) Plastids C) Golgi apparatus C) 4 13. The number of lenses in compound light microscope is/are: A) 2 B) 3 14. Identify the following image and choose the correct option Avanti – 9B01 – Fundamental Unit of Life –CBSE Practice Problems

8 A) Cell of cheeks B) Cell of onion peels C) Cell of cork cambium D) None of these 15. Identify the following cells and match them with the incorrect options A) Bone cells ՜ B) Nerve cells ՜ C) Smooth muscle cell ՜ D) Sperm cell ՜ 16. The free living cells in the pond water were discovered by B) Robert Hooke D) Camillo Golgi A) Anton Von Leewenhoek C) Robert Brown 17. Name two cell organelles which contain their own genetic material A) Mitochondria and lysosomes B) Golgi apparatus and Endoplasnic Reticulum C) Nucleus and mitochordria D) Lysosomes and Ribosomes 18. Eukaryotic cells ranges in size from A) 5 െ 100 ݊݉ B) 1 െ 10 ߤ݉ C) 5 െ 100 ߤ݉ D) 1 െ 10 ݊݉ 19. Which of the following is the incorrect statement with respect to cell? A) Cell is the basic unit of life B) A single cell may constitute a whole organism C) All cells do not arise from pre-existing cells D) All living organisms are composed of cells 20. In which of the following process, the substance move across the membrane without the expenditure of ATP A) Exocytosis B) Active tronsport C) Diffusion D) Endocytosis 21. Ribosomes are associated with B) Respiration D) Fat synthesis A) ATP Synthesis C) Protein Synthesis Avanti – 9B01 – Fundamental Unit of Life –CBSE Practice Problems

22. A plant cell becomes swollen due to 9 A) Exosmosis B) Plasmolysis C) Endosmosis D) Electrolysis 23. Which of the following cell is visible to human eye? A) Blood Cell B) Smooth muscle cell C) Egg of ostrich D) Sperm cell 24. Which of the following is a unicellular organism? A) Cladophora B) Yeast C) Marsilea D) Funaria 25. Which cell organelle provides the pathway for the distribution of nuclear material? A) Ribosomes B) Endoplasmic Reticulum C) Golgi Apparatus D) Vacuole Avanti – 9B01 – Fundamental Unit of Life –CBSE Practice Problems

10 9B01 – Fundamental Unit of Life – Olympiad Practice Problems INSTRUCTIONS Answer each of the following questions. 1. Select the correct statement regarding cell wall of plant cells. A) Primary cell wall is chiefly composed of a soluble fibrous polysaccharide called suberin. B) Secondary cell wall is mainly composed of lignin and is deposited on the outer surface of primary wall. C) Pits are present in primary walls whereas they are absent in secondary walls. D) The primary cell walls of adjacent cells are cemented through middle lamella which is composed of calcium and magnesium pectate. 2. Anaya took a few stalks of celery and immersed them in solution X. After 10 minutes, the stalks became swollen. Simi- larly, she immersed some celery stalks in solution Y, which after 10 minutes became shrunken. What can you deduce from this observation? A) Solution X is hypotonic, while solution Y is hypertonic for celery stalks. B) Solution X is hypertonic, while solution Y is hypotonic for celery stalks. C) Solution X is isotonic, while solution Y is hypertonic for celery stalks. D) Solution X is hypotonic, while solution Y is isotonic for celery stalks. 3. Shefali classified the functions of cell organelles as given in the table below. Group A Group B Group C Group D Endocytosis & exocytosis Freely permeable. Storage, modification & Synthesis and transport of Provides shape and rigidity packaging of secretory proteins & fats. To the cell. products. Group D Which of the following have the correct headings for the given table? Group A Group B Group C A) Cell wall Cell membrane Golgi body Endoplasmic reticulum B) Cell membrane Cell wall Endoplasmic reticulum Golgi body C) Cell wall Cell membrane Endoplasmic reticulum Golgi body D) Cell membrane Cell wall Golgi body Endoplasmic reticulum 4. Which of the following statements is correct about the lack of organelles in prokaryotes? A) The lack of organelles in prokaryotes means that their basis cellular processes are different from eukaryates. B) It suggests that the amount of DNA remains the same throughout the life cycle. C) Absence of organelles in prokaryotes means that they cannot perform the function of photosynthesis. D) It suggests that they contain more variety of phospholipids in their cell membrane. 5. Refer to the given venn diagrams and select the incorrect option regarding structures V, W, X, Y and Z. A) V could be an outermost protective covering, which is composed of lipo-polysaccharides in bacteria and cellulose in plants. B) ܻ could be a membrane- less organelle involved in protein synthesis whereas Z could be an ingrowth of cell membrane that contains respiratory enzymes. C) Both ܹ and ܺ could be double membrane structures but inner membrane of ܹ is smooth whereas that of ܺ is thrown into folds. D) ܹ takes part in photosynthesis whereas ܼ connects genetic material with plasma membrane. Avanti – 9B01 – Fundamental Unit of Life – Olympiad Practice Problems

6. The given diagram shows a cell placed in a concentrated solution. What would happen when the cell is taken out from 11 the concentrated solution and is placed in freshwater for a long time? i) The cell will recover its shape slowly. ii) The cell will shrink first. iii) The cell will burst eventually. iv) Water molecules will diffuse into the cell by osmosis. Select the correct option. A) I and II B) IV only C) I, III and IV D) I, II, III and IV 7. Which of the following match is incorrect? i) Diffusion - Movement of substances from higher concentration to lower concentration - Occurs in only one direction. ii) Osmosis - Prevents passage of solute molecules Withdrawal of water from the vacuole iii) Semi-permeable membrane Shrinkage of protoplasm when kept in hypotonic solution iv) Endosmosis - v) Plasmolysis - A) (ii), (iv) & (v) B) (iv) & (v) C) (i), (iii) & (iv) D) (iv) only 8. Categorise the following functions respectively associated with the given cell organelles ܲ and ܳ. i) Work as a seat of protein synthesis. ii) Helps in secretion of mucus, enzymes and hormones. iii) Help in storage of secretory products. iv) Helps in development of acrosome of sperm. v) Helps in membrane biogenesis. vi) Froms a continuous transport channel with nuclear membrane. A) P-(i), (ii), (v); Q-(iii), (iv), (vi) B) P-(iii), (iv), (v); Q-(i), (ii), (vi) C) P-(ii), (iii), (iv); Q-(i), (v), (vi) D) P-(i), (ii), (iii), (iv); Q-(v), (vi) 9. A scientist was studying the production of a protein, that was released by an animal cell into a culture medium. She found that the protein only appeared in the culture medium after she added a few drops of a hormone to the cell. Be- fore adding the hormone, she labelled the protein inside the cell with a fluorescent dye was seen in flattened sheets and tube-like structures throughout the cell, and in stacks of flattened sac-like structures. After adding the hormone, the dye was also seen as small dots clustered against the cell membrane. Which statement most likely explains these observations? A) The hormone stimulates protein synthesis in the cell vacuole; the protein is then passed to the Golgi apparatus, and eventually passes through the cell membrane by passive diffusion. B) The hormone triggers the synthesis of the protein in the endoplasmic reticulum which is then secreted in the en- doplasmic reticulum which is then secreted outside the cell via channel proteins in the cell membrane. C) The protein is made in the endoplasmic reticulum, which is next passes to the Golgi apparatus, and then secreted throught hormone-stimulated exocytosis. D) The protein is made in the Golgi apparatus, which is then passed to the endoplasmic reticulum, is then passed to the endoplasmic reticulum, and finally secreted through hormone-stimulated pinocytosis. 10. The diagram shows five different structures that can be ob- served in cells. Which structures would be present in large quantities in lipid synthesizing cell? A) 1, 2, 4 and 5 B) 1, 3 and 4 C) 2, 3 and 5 D) 3, 4 and 5 Avanti – 9B01 – Fundamental Unit of Life – Olympiad Practice Problems

11. A single-celled organism which has contractile vacuole to move water from inside to outside of the cell was studied in 12 an experiment in which the organism was placed in water with different salt concentrations. The rate at which the contractile vacuole contracted to pump out excess water was recorded. Salt cone. Rate of contractile vac- uole contractions per minute Very high 2 High 8 Medium 15 Low 22 Very low 30 Which of the following explains the observed relationship between the rate of contractile vacuole contraction and the salt concentration? A) When the salt concentration outside the cell is very low, osmosis causes body salts to move outside the cell, in- creasing water content in body and the contractile vacuole needs to contract rapidly. B) When the salt concentration outside the cell is very high, diffusion causes water to move outside the cell, and the contractile vacuole does not need to contract as rapidly. C) When the salt concentration outside the cell is very low, diffusion causes water to move outside the cell, and the contractile vacuole contractions. D) When the salt concentration outside the cell is very high, osmosis causes water to move outside the cell, and the contractile vacuole does not need to contract as rapidly. 12. Read the following statement and select the correct option. Statement 1: In a mature plant cell, the nucleus and cell organelles are pushed against the cell wall. Statement 2: The plant cell have single and large central vacuole which occupies 50 െ 90% of the cell volume. A) Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1. B) Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1. C) Statements 1 is false and statement 2 is true. D) Statements 1 is true and statement 2 is false. 13. Four strips of fresh potato ܲ, ܳ, ܴ and ܵ were immersed in solution of different concentrations. Osmosis occurred according to the concentra- tion difference between cell sap and ambient solution. A graph was plot- ted between initial length of strips and the change in length after osmo- sis. Which of these strips was placed in the most diluted solution? A) S B) Q C) R D) P 14. Find out the false sentence. A) Golgi apparatus is involved in the formation of lysosomes. B) Nucleus, mitochondria and plastid have DNA; hence they are able to make their own structural proteins. C) Mitochondria is said to be the power house of the cell as ATP is generated in them. D) Cytoplasm is also called protoplasm. 15. While observing a stained mount of onion peel under high power compound microscope, the following options cor- rectly identifies the central part of the cell ? A) Nucleus B) Cell wall C) Vacuole D) Chloroplast Avanti – 9B01 – Fundamental Unit of Life – Olympiad Practice Problems

16. Refer to the given diagram which shows a root hair cell surrounded by a dilute solution of mineral ions. 13 The mineral ions show B) Uphill movement by active transport D) Downhill movement by active transport. A) Uphill movement by diffusion C) Downhill movement by osmosis 17. Match column I with column II and select the correct option from the given codes. Column I Column II a) Ribosomes i) Jelly like substance b) Lysosomes ii) Powerhouse of the cell c) Endoplasmic reticulum iii) Site of protein synthesis d) Cytoplasm iv) Synthesis of lipids e) Mitochondria v) Suicide bags A) (a)-(iii), (b)-(v), (c)-(iv), (d)-(i), (e)-(ii) B) (a)-(iv), (b)-(v), (c)-(iii), (d)-(i), (e)-(ii) C) (a)-(iii), (b)-(iv), (c)-(i), (d)-(v), (e)-(ii) D) (a)-(iv), (b)-(v), (c)-(ii), (d)-(i), (e)-(iii) 18. Study the given diagram representing the process of osmosis and select the correct statement regarding this. A) Limb ܲ of the ܷ-tube functions like the root hair of a plant for the absorption of water. B) Net movement of sucrose molecules takes place from limb ܳ to limb ܲ of the ܷ-tube. C) Net movement of water molecules takes place from limb ܲ to limb ܳ of the ܷ- tube. D) Semi-permeable membrane allows only solute sucrose molecules to pass through it. 19. The materials commonly used for staining and mounting human cheek cells respectively. A) Safranin and glycerine B) Methylene blue and glycerine C) Safranin and methylene blue D) Fast green and glycerine. 20. Read the following statements associated with the given cell organelles ܺ and ܻ. i) ܺ works as a seat of protein synthesis. ii) ܻ helps in exhange of materials between the cytoplasm and the nucleus. iii) ܺ help in storage of secretory products. iv) Both ܺ and ܻ help in membrane biogenesis. v) ܺ usually forms a continuous transport channel with nuclear membrane. Which of the above statements are correct ? A) (i), (ii), (iii) and (v) only B) (i), (iv) and (vi) only C) (ii),(iii) and (v) only D) (iii), (iv), (v) and (vi) only Avanti – 9B01 – Fundamental Unit of Life – Olympiad Practice Problems

21. Direction : Refer to the given dichotomous key regarding cell organelles and answer the questions 21 and 22. 14 21.(I) (a) surrounded by a double unit membrane. … Go to (II) (b) not surrounded by a double unit membrane. … Go to (iv) (II) (a) Membrane with definite pores. ܲ (b) Membrane with no definite pores … Go to (III) (III) (a) Inner membrane with stalked particles. ܳ (b) inner membrane folded into thylakoids. ܴ (IV) (a) contains digestive enzymes. ܵ (b) composed of one large subunit and one small subunit. ܶ Identify the cell organelles ܲ, ܳ, ܴ, ܵ and ܶ and select the correct option regarding these. A) ܲ can be ‫ ܴܧ‬and ܳ can be Golgi apparatus. B) ܴ can be chloroplasts and ܵ can be ribosomes. C) ܲ can be nucleus and ܶ can be ribosomes. D) ܴ can be mitochondria and ܵ can be lysosomes. 22. Select the incorrect option regarding the given dichotomous key. A) The organelles ܳ and ܴ are present but poorly developed in prokaryotes. B) The organelles ܳ and ܴ possess their own genetic material. C) The organelle ܶ is present in both prokaryotic and eukaryotic cells. D) The organelle ܵ plays an important role at the time of fertilisation in human beings. 23. Find out the incorrect statement. A) Osmosis is a slow process, occurs down the concentration gradient and does not expend energy. B) Electron microscope uses very high voltage electricity. It uses electromagnets instead of glass lenses and beam of electrons instead of light. C) A semi-permeable membrane does not allow both solvent and solute molecules to pass through it. D) Active transport of materials is rapid and usually occurs against the concentration gradient involving carrier pro- teins and energy in the form of ATP. 24. A strain of an animal exists in wild in which there is only one nucleolus in the nucleus of each cell instead of the usual two. When such animals are mated, approximately one quarter of the offspring have two nucleoli per nucleus, one half have no nucleolus at all. Offspring without nucleoli die about four days after hatching. These offspring die because they do not possess. A) Mitochondria are unable to obtain energy. B) Centrioles are unable to undergo cell division. C) Golgi apparatus are unable to remove dead cells. D) Ribosomes are unable to manufacture proteins. 25. Refer to the given diagram of an animal cell and select the option that correctly de- scribes the functional relationship between organelles ܲ and ܳ. A) Polypeptides synthesised at ܳ are transported to ܲ where they are stored for regular use in cytoplasm. B) Polypeptides synthesised at ܳ are transported to ܲ where they are modified in- to functional proteins for secretion. C) Polypeptides synthesised at ܲ are packaged into vesicles that move to ܳ for fur- ther modification. D) Polypeptides synthesises at ܲ are packaged without modification and move to ܳ where they are stored for regular use in cytoplasm. Avanti – 9B01 – Fundamental Unit of Life – Olympiad Practice Problems