1 BASIC BIOLOGY I. Multiple choice questions: Tick mark ( ) the correct choice. 1. Cell was discovered by (a) Robert Brown (b) C. Linnaeus (c) Robert Hooke (d) C. Darwin Ans. (c) 2. Each cell has a (a) nucleus (b) cell wall (c) chloroplast (d) all the above 3. The cell is surrounded by a membrane called (a) cell wall (b) cell membrane (c) cytoplasm (d) nuclear membrane Ans. (b) 4. Organelles are present in (a) cytoplasm (b) vacuoles (c) nucleus (d) all the above 5. A cell organelle commonly called suicide bag is (a) nucleus (b) lysosome (c) chloroplast (d) ribosome Ans. (b) 6. The cell membrane is (a) impermeable (b) selectively permeable (c) freely permeable (d) none of the above Ans. (b) 7. The thread-like structures which are visible only during cell division are called (a) chromosomes (b) lysosomes (c) genes (d) centriole 8. Longest cell of an animal s body is usually the (a) nerve cell (b) muscle cell (c) liver cell (d) red blood cell Biology Class VII 1 Question Bank
9. Smallest cell among the following is (a) red blood cell (b) bacteria (c) white blood cell (d) liver cell Ans. (b) 10. The term cell in biology was given by (a) Robert Hooke (b) Aristotle (c) Leeuwenhoek (d) Robert Brown 11. The cell wall is made up of (a) proteins (b) fats (c) cellulose (d) vitamins Ans. (c) 12. An organelle not bound by a membrane is the (a) nucleus (b) chloroplast (c) mitochondrion (d) ribosome Ans. (d) 13. In a cell, proteins are formed with the help of (a) nucleus (b) golgi bodies (c) mitrochondria (d) ribosomes Ans. (d) 14. The powerhouse of a cell is the (a) chloroplast (b) mitochondrion (c) centrosome (d) cell wall Ans. (b) 15. The infolding of the inner membrane of a mitochondrion is called (a) matrix (b) cisternae (c) cristae (d) vesicles Ans. (c) 16. The green pigment in the chloroplast is present in its (a) outer membrane (b) matrix (c) grana (d) all of the above Ans. (c) 17. The centrosome has (a) two centrioles (b) one centriole (c) three centrioles (d) four centrioles Biology Class VII 2 Question Bank 2
18. The membrane surrounding the vacuole is called (a) plasma membrane (b) nuclear membrane (c) tonoplast (d) cell wall Ans. (c) 19. Which one of the following is present only in animal cell? (a) Plastids (b) Centriole (c) Chloroplast (d) Cell wall Ans. (b) 20. Which of the following contains digestive enzymes? (a) Lysosome (b) Centriole (c) Mitochondria (d) Nucleolus 21. Cell division is needed for (a) growth (b) repair (c) reproduction (d) all the above Ans. (c) 22. Which of the following is not a cell organelle? (a) Latex (b) Chloroplast (c) Nucleus (d) Ribosome II. State whether the following statements are True or False. 1. Most of the cells have only one nucleus. 2. Only the nucleus of a cell represents the protoplasm. 3. All living organisms are made of cells. 4. Cells must have a nucleus to live. 5. Every cell has cytoplasm. 6. The outermost covering in an animal cell is called cell wall. 7. The cell is the fundamental structural and functional unit of all living organisms. 8. Protoplasm is divided into two parts, the nucleus and the cytolplasm. 9. Since nerve cells are elongated, it enables them to make an efficient system for communication. 10. The muscle cells are contractile which help in the movement of bones. 11. Amoeba is an irregular cell. Biology Class VII 3 Question Bank
12. Organisms whose body is formed of just one cell are called multicellular. 13. Ostrich egg is the largest cell. 14. The cell wall is made up of cellulose. 15. The size of a cell is measured in centimetres. 16. Every cell is bound by a cell wall. 17. The nuclear membrane encloses a colourless, dense fluid called nucleoplasm. 18. A mitrochondrion is bound by two membranes. 19. Vacuoles are filled with a fluid called nucleoplasm. 20. Ribosomes are the sites of respiration in a cell. 21. Chromoplasts are the kitchen of the cell. 22. Plastids in a leaf that give it green colouration are called chloroplast. 23. Centrosome is called the powerhouse of the cell. 24. Plant cells and animal cells have a cell wall. 25. Cell division occurs only in animal cells. 26. Centrosome is present only in plant cells. 27. Mitochondria are the power houses of a cell. 28. All cells have walls made of cellulose. 29. Animals cells have larger vacuoles. 30. Chromosomes have chlorophyll. Ans. 1. True 2. False 3. True 4. True 5. True 6. False 7. True 8. True 9. True 10. True 11. True 12. False 13. True 14. True 15. False 16. False 17. True 18. True 19. False 20. False 21. False 22. True 23. False 24. False 25. False 26. False 27. True 28. False 29. False 30. False. III. Match the statements in column A with those in column B. Column A Column B 1. Cell (a) Unit of living body 2. Nucleus (b) Boss of the cell 3. Cytoplasm (c) Jelly-like substance between cell membrane and nucleus 4. Ribosomes (d) help in cell division Biology Class VII 4 Question Bank 4
Column A Column B 5. Mitochondria (e) transport of material 6. Endoplasmic reticulum (f) digesting foreign bodies 7. Golgi bodies (g) makes the cell turgid 8. Centrosome (h) making proteins 9. Vacuole (i) releasing energy 10. Lysosomes (j) synthesis of cell wall in a plant well 11. Chromosome (k) contains pigments 12. Plastids (l) hereditary material Ans. 1. a 2. b 3. c 4. h 5. i 6. e 7. j 8. d 9. g 10. f 11. l 12. k. IV. Select suitable words given here to match the statements under column A. Write the selected word in the appropriate place under Column B. [List of words: Mitochondria, cytoplasm, cell wall, lysosome, centrioles, ribosome, vacuole, nucleus, chromosome, chlorophyll, plastid, Golgi apparatus, centrosome.] Column A Column B 1. The substance is transferred from one generation... to another. 2. It provides energy for the cell.... 3. It contains enzymes which destroys the dead or... injured cell. 4. It traps the sunlight.... 5. It is made up of cellulose.... Ans. 1. Chromosomes 2. Mitochondria 3. Lysosomes 4. Chlorophyll 5. Cell wall V. Fill in the blanks. 1. The... is the control centre of the cell. 2. The instrument used to see tiny objects is called.... 3. An... is a cell that can be seen without a microscope. Biology Class VII 5 Question Bank
4. The term cell was given by.... 5. A plant cell gets shape and support from its.... 6. The cell wall is made up of a complex chemical substance called.... 7. The jelly-like fluid that surrounds the nucleus of a cell is called.... 8.... is called the powerhouse of a cell. 9. The organelles involved in the synthesis of proteins are the.... 10. In a plant cell photosynthesis occurs in.... 11.... give colour to flowers and fruit. 12. Fluid-filled cell organelles that are usually larger in a plant cell than in an animal cell are called.... 13. Cell shape is related to its.... 14.... is the unit of life. 15. One micron is... of a metre. 16. The largest cell in the animal kingdom is that of an... egg. 17. Single-celled organisms are called.... 18.... is the smallest cell in the human body. 19. Cells are measured in.... 20.... takes part in animal cell division. Ans. 1. Nucleus 2. Microscope 3. Egg 4. Robert Hooke 5. Cell wall 6. Cellulose 7. Cytoplasm 8. Mitochondrion 9. Ribosomes 10. Chloroplasts 11. Chromoplasts 12. Vacuoles 13. Function 14. Cell 15. 10 6 16. Ostrich 17. Unicellular organism 18. R.B.C. 19. Micron 20. Centrosome. VI. Given below is a list of cell structures and cell contents: Cytoplasm, chloroplasts, starch grains, nucleus, vacuole, glycogen granules, cell wall, chromosomes, cell membrane, mitochondria. Categorise these under the following three categories: (a) Found in animals cell only. (b) Found is plant cells only. Biology Class VII 6 Question Bank 6
(c) Found in both animal and plant cells. Glycogen granules (b) Chloroplasts, starch grains, cell wall, Vacuole (c) Cytoplasm, nucleus, chromosomes, cell membrane, mitochondria. VII. Assign one function for the following cells: (i) The nerve cells are long... (ii) The muscle cells are elongated and contractible... Ans. (i) Long shape of nerve cell enables them to send messages over long distances. (ii) The muscle cells are elongated and contractible. Due to this feature, movement in the bones occurs. VIII. Give on example of each of the following: (i) Largest cell... (ii) A contractile cell... Ans. (i) Ostrich egg (ii) Muscle cell IX. Cell division is essential for (tick-mark the four correct functions). (i) growth of the organism. (ii) nutrition of the organism. (iii) replacement of dead cells. (iv) excretion of the waste products. (v) repair of injuries. (vi) sexual reproduction. Ans. (i), (iii), (v), (vi). X. Give reasons: (a) Study of cells could not start before the 17th century. Ans. Before 17th century, it was impossible to study the cells. Because at that time we have no microscope. After 17th century, invention of light microscope and then electron microscope, makes it easy to study the cell. (b) Mitochondria are called the powerhouses of the cell. Ans. Mitochondria are called powerhouse of cell because these are Biology Class VII 7 Question Bank
the sites of respiration in the cell. Food is oxidised in the presence of oxygen and energy is released. XI. The diagram given here shows a diagrammatic sketch of a plant cell. A list of the parts it contains is given below: Chloroplast, Plasma membrane, Vacuole, Cell-wall, Cytoplasm, Nucleus. (i) Name the parts (1-5) indicated by guidelines choosing the correct words from the above list. (ii) Mention three parts of the cell which indicate that it is a plant cell. (iii) State the function of the part labelled 2 and 6. Ans. (i) (1) Cell wall (2) Plasma membrane (3) Chloroplart (4) Cytoplasn (5) Nucleus (6) Vacuole (ii) Three points which indicate that it is a plant cell: (1) Presence of cell wall (2) Presence of large vacuoles (3) Presence of chloroplast (iii) Plasma membrane. It controls the movement of materials in and out of the cell. It allows certain substances to pass through it. Hence, it is called a selectively permeable membrane. Vacuole: Vacuoles helps the cell to remain turgid. They store materials and water in the cell. XII. Given below is the diagram of a generalized cell as seen under an electron microscope. (i) It is an animal cell or plant cell. Ans. It is an animal cell because cell wall is absent. (ii) Name the parts indicated by guidelines 1-7. Ans. (1) Nucleus (2) Ribosomes Biology Class VII 8 Question Bank 8
(3) Nucleolus (4) Plasma membrane (5) Endoplasmic reticulusm (6) Mitochondria (7) Cytoplasm (iii) Give one function of each of the part 1, 5 and 6. Ans. Nucleus. It controls all the vital activities of the cell. So it is called control centre of the cell Endoplasmic reticulum. It provides a pathway for the transport of material within the cell and often between cells. Mitochondria. It is called powerhouse of the cell. Food is oxidised in the presence of oxygen and energy is released. XIII.Complete this table: Structure Function (i) Supports and protects the cell (ii) Mitochondria (iii) Centrosome (iv) Contains various coloured pigments. Ans. (1) Plasma membrane Supports and protects the cell (2) Mitochondria Powerhouse of the cell (3) Centrosome Helps in cell division (4) Plastids Contains various coloured pigments. XIV. Name the following: (i) The non-living structures found in the cytoplasm. Ans. Granules (ii) The organelle in the cell that synthesize energy. Ans. Mitochondria (iii) The controlling centre of the cell Ans. Nucleus (iv) The scientist who invented the first microscope Ans. Robert Hooke (v) Any one structure to identify a plant cell. Ans. Cell wall Biology Class VII 9 Question Bank
XV. Answer the following questions. 1. Give three examples of unicellular organisms. Ans. Three unicellular organisms: (i) Amoeba (ii) Paramecium (iii) Chlamydomonas 2. Mention the functions of the following: (i) Cell membrane (ii) Chloroplast (iii) Mitochondria Function of cell membrane (i) It controls the movement of material in and out of the cell. It is called selectly permeable membrane because it allows only certain substances to pass through it and others are prevented. (ii) It provides protection to the cell organelles. (iii) It gives shape to the cells. (b) Functions of chromosomes Chromosomes are present in nucleus and play an important role in the inheritance of characters from one generation to another, i.e., from parents to children. 3. Why are the following important to a plant cell? (i) Cell wall (ii) Chloroplast (iii) Mitochondria (iv) Nucleus Ans. (i) Cell wall. Cell wall is non-living part of plant cell and made up of complex carbohydrate called cellulose. It is important to plant cells because it gives a definite shape to the cell and provide rigidity and strength to it. (ii) Chloroplast. It is very important to plants because it contains chlorophyll that trap solar energy to manufacture food. These are also called kitchen of the cell. (iii) Mitochondria. Mitochondria are called powerhouse of the cells. They are the site of respiration in the cell. Food is oxidised in the presence of oxygen and energy is released. (iv) Nucleus. It is the largest cell organelle. It contains threadlike structures called chromosomes that carry genes. These Biology Class VII 10 Question Bank 10
genes are responsible for hereditary characters. It is also called the control centre of the cell because it controls all the vital activities of the cell. We can say that it is the head-office of the cell. 4. Which cell organelle is found only in animal cells? Ans. Centrosome is the cell organelle that is present only in animal cell. It is non-membranous organelle and has two tiny cylindrical structures called centrioles. 5. Mention at least four differences between plant cells and animal cells. Ans. Difference between plant cell and animal cell. Plants cell Animals cell (1) Cell wall is present around (1) Cell wall is absent. cell membrane. (2) Plastids are present. (2) Plastids are absent. (3) Centrosomes are absent. (3) Centrosomes are present. (4) Large vacuoles are present. (4) Vacuoles are absent. If present, they are very small. 6. What features are possessed by both plant cells and animal cells? Ans. Similarities between plant cell and animal cell. (1) Plant cell and animal cell both have cell membrane. (2) Both cells contain all the cell organelles except plastids and cell wall in plant cells and centrosome in animal cells. (3) Plant and animal cells both have reserve food materials in the form of starch and glycogen respectively. 7. Name the cell organelles which are found only in the plant cell. Ans. Plastids are present only in plant cell. These are doublemembrane bound cell organelles. 8. Name the different cell organelles and the functions which perform in the cell. Biology Class VII 11 Question Bank
Ans. Different cell organelles and their functions. (i) Nucleus. It is the largest cell organelle. It contains threadlike structures called chromosomes that carry genes. These genes are responsible for hereditary characters. It is also called the control centre of the cell because it controls all the vital activities of the cell. We can say that it is the headoffice of the cell. (ii) Endoplasmic reticulum. It provides a pathway for the transport of material within the cell. It gives internal support to the cell. (iii) Ribosomes: These are the main sites of protein synthesis. These are also called protein factory. (iv) Mitochondria. In mitochondria food is oxidised in the presence of oxygen and energy is released. So, these are also called powerhouses of the cell. (v) Golgibody. These help in the synthesis of cell wall in plant cells. (vi) Plastids. (a) They use solar energy and manufacture food for the plants. (Chloroplast) (b) They imparts colour to fruits and flowers. (Chromoplasts). (c) They store food prepared in the plant in the form of starch, proteins and fats. (Leucoplasts) (vii) Lysosomes. (a) They are called suicide bags because in certain condition they release digestive enzymes that digest the dead and damged cell organelles. (b) They protect the cell against various foreign bodies. (c) They contain many digestive enzymes which help in the digestion of food material. 9. Mention the two types of cell division. Ans. Cell division in most of the organisms is of two types: (a) Mitosis (b) Meiosis. Mitosis takes place in normal cells and responsible for growth of organisms. Biology Class VII 12 Question Bank 12
Meiosis takes place in reproductive cells and is responsible for the passing on of characters from the two parents to the child. 10. How do cells increase in number? Ans. Cell increase in number due to cell division. Cells division is an important characteristic of living beings. Most of the cells are capable of growing and splitting into two similar cells. These cells are indentical to the mother cell. During cell division, firstly nucleus divides into two parts followed by the division of cytoplasm. Finally, two daughter cells are formed. 11. Why is a cell called the structural unit of a living organism? Ans. All the plants and animals are made up of cells. If we examine any structures from plants or animals microscopically, they will be seen to consist of more or less distinct units called cells. Groups of cells of the same type make up the different tissues of the organism, e.g., muscle tissue. Several different types of tissues together form an organ, e.g., stomach. A number of organs together form a system, e.g., digestive system. Hence, a cell is called the structural unit of a living organism. 12. Why was the invention of the microscope so important to the study of living things? Ans. Any living organisms is made up of microscopic units called cells. These cells are too small that we can not see them with naked eyes. With the invention of microscope, it is convenient to study these tiny structures. First the simple microscope and then compound microscope and electron microscope are the great inventions in the cell biology. 13. What is cell theory? Name the three scientists whose work led to the formulation of the cell theory. Ans. Cell theory was given by three scientists- Schleiden, Schwann and Virchow. According to this theory (i) All living things are made of one or more cells. (ii) Cells are the basic structural and functional unit of all living things. Biology Class VII 13 Question Bank
(iii) New cells come from pre-existing cells. 14. Why is the cell membrane called selectively permeable membrane? Ans. Cell membrane is called selectively permeable membrane because it controls the movement of material in and out of the cell. It also allows only certain substances to pass through it and others are prevented. 15. Which structure of a plant cell is non-living and what are its functions? Ans. Cell wall is a non-living part of the cell. It is made up of complex carbohydrate called cellulose. It gives a definite shape to the cell and provides strength and rigidity to it. It is only the characteristic of plant cells not animal cells. 16. Explain the structure and the functions of the nucleus. Ans. Nucleus is the largest cell organelle. Most of the cells have single nucleus. It is spherical or oval in shape. It is surrounded by double membrane called nuclear membrane and contain a colourless, dense fluid called nucleoplasm. In nucleoplasm, some spherical bodies are embeded called nucleoli. In nucleoplasm, some thread-like structures form a network called chromatin network. These thread-like structures are called chromosomes. These chromosomes carry genes which are responsible for hereditary characters. Since, nucleus controls all the vital activities of the cell so it is also called control centre of the cell. 17. Where are the genes located in a cell? Ans. Genes are located on the chromosomes which are present in the nucleus. 18. The cells in a potato tuber do not have chloroplasts. How would you identify its cells as plant cells by observing them under a microscope? Biology Class VII 14 Question Bank 14
Ans. All the plant cells have a characteristic property, i.e., the presence of cell wall. The cells in potato tuber do not have chloroplasts. But under microscope, we can see the cell wall and deside it that it is a plant cell. 19. What is the relationship between growth and cell division? Ans. Growth is directly proportional to the cell division. In multicellular organisms more the cell divisions more will be the growth. Due to the cell division a seedling grows into a big plant and a newborn changes into an adult. Thus, we can say that cell division is the process by which a cell divides, forming two new cells. 20. How will you differentiate cell wall from plasma membrane? Ans. In plant cells an additional covering is present around plasma membrane that provide strength and rigidity to the cell. This additional covering is called cell wall. It is made of complex carbohydrate called cellulose whereas plasma membrane is made of proteins. 21. What are plastids? State two of its main functions. Ans. Plastids are the double membrane-bounded cell organelles which are present only in plant cells. Plastids have following functions: (i) They use solar energy and manufacture food for the plants (chloroplasts). (ii) They imparts colour to fruits and flowers (chromoplasts). (iii) They store food prepared in the plants in the form of starch proteins and fats (leucoplasts). **** Biology Class VII 15 Question Bank