NCERT Exemplar Solutions for Class 9 Science Chapter 5 The Fundamental Unit of Life (MCQ, SAQ and LAQ)
Chapter Name | NCERT Exemplar Solutions for Class 9 Science Ch 5 The Fundamental Unit of Life |
Topics Covered |
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Related Study |
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Objective Type Questions for The Fundamental Unit of Life
1. Which of the following can be made into crystal?
(a) A bacterium
(b) An amoeba
(c) A virus
(d) A sperm
Solution
(c) A virus
2. A cell will swell up if :
(a) The concentration of water molecules in the cell is higher than the concentration of water molecules in surrounding medium.
(b) The concentration of water molecules in surrounding medium is higher than water molecules concentration in the cell.
(c) The concentration of water molecules is same in the cell and in the surrounding medium.
(d) Concentration of water molecules does not matter.
Solution
(b) The concentration of water molecules in surrounding medium is higher than water molecules concentration in the cell.
3. Chromosomes are made up of :
(a) DNA
(b) protein
(c) DNA and protein
(d) RNA
Solution
(c) DNA and protein
4. Which of these options are not a function of ribosomes?
(i) It helps in manufacture of protein molecules
(ii) It helps in manufacture of enzymes
(iii) It helps in manufacture of hormones
(iv) It helps in manufacture of starch molecules
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (iv) and (i)
Solution
(c) (iii) and (iv)
5. Which of these is not related to endoplasmic reticulum?
(a) It behaves as transport channel for proteins between nucleus and cytoplasm.
(b) It transports materials between various regions in cytoplasm.
(c) It can be the site of energy generation.
(d) It can be the site for some biochemical activities of the cell.
Solution
(c) It can be the site of energy generation.
6. Following are a few definitions of osmosis, read carefully and select the correct definition :
(a) Movement of water molecules from a region of higher concentration to a region of lower concentration through a semipermeable membrane.
(b) Movement of solvent molecules from its higher concentration to lower concentration.
(c) Movement of solvent molecules from higher concentration to lower concentration of solution through a permeable membrane.
(d) Movement of solute molecules from lower concentration to higher concentration of solution through a semipermeable membrane.
Solution
(a) Movement of water molecules from a region of higher concentration to a region of lower concentration through a semipermeable membrane.
7. Plasmolysis in a plant cell is defined as :
(a) Break down (lysis) of plasma membrane in hypotonic medium
(b) Shrinkage of cytoplasm in hypertonic medium
(c) Shrinkage of nucleoplasm
(d) None of the above
Solution
(b) Shrinkage of cytoplasm in hypertonic medium
8. Which of the following are covered by a single membrane?
(a) Mitochondria
(b) Vacuole
(c) Lysosome
(d) Plastid
Solution
(b) Vacuole, (c) Lysosome
9. Find out the false sentences :
(a) Golgi apparatus is involved with 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 powerhouse of the cell as ATP is generated in them.
(d) Cytoplasm is called as protoplasm.
Solution
(a) Golgi apparatus is involved with the formation of lysosomes.
10. Find out the correct sentence :
(a) Enzymes packed in lysosomes are made by RER (rough endoplasmic reticulum).
(b) Rough endoplasmic reticulum and smooth endoplasmic reticulum produce lipid and protein respectively.
(c) Endoplasmic reticulum is related with the destruction of plasma membrane.
(d) Nucleoid is present inside the nucleoplasm of eukaryotic nucleus.
Solution
(a) Enzymes packed in lysosomes are made by RER (rough endoplasmic reticulum).
11. Which cell organelle plays a crucial role in detoxifying many poisons and drugs in a cell?
(a) Golgi apparatus
(b) Lysosomes
(c) Smooth endoplasmic reticulum
(d) Vacuoles
Solution
(c) Smooth endoplasmic reticulum
12. The proteins and lipids, essential for building the cell membrane, are manufactured by :
(a) rough endoplasmic reticulum
(b) golgi apparatus
(c) plasma membrane
(d) mitochondria
Solution
(a) rough endoplasmic reticulum
13. The undefined nuclear region of prokaryotes are also known as :
(a) nucleus
(b) nucleolus
(c) nucleic acid
(d) nucleoid
Solution
(d) nucleoid
14. The cell organelle involved in forming complex sugars from simple sugars are :
(a) endoplasmic reticulum
(b) ribosomes
(c) plastids
(d) Golgi apparatus
Solution
(d) Golgi apparatus
15. Which out of the following is not a function of vacuole?
(a) Storage
(b) Providing turgidity and rigidity to the cell
(c) Waste excretion
(d) Locomotion
Solution
(d) Locomotion
16. Amoeba acquires its food through a process, termed :
(a) exocytosis
(b) endocytosis
(c) plasmolysis
(d) exocytosis and endocytosis both
Solution
(b) endocytosis
17. Cell wall of which one of these is not made up of cellulose?
(a) Bacteria
(b) Hydrilla
(c) Mango tree
(d) Cactus
Solution
(a) Bacteria
18. Silver nitrate solution is used to study :
(a) endoplasmic reticulum
(b) Golgi apparatus
(c) nucleus
(d) mitochondria
Solution
(b) Golgi apparatus
19. Organelle other than nucleus, containing DNA is :
(a) endoplasmic reticulum
(b) Golgi apparatus
(c) mitochondria
(d) lysosome
Solution
(c) mitochondria
20. Kitchen of the cell is :
(a) mitochondria
(b) endoplasmic reticulum
(c) chloroplast
(d) golgi apparatus
Solution
(c) chloroplast
21. Lipid molecules in the cell are sythesized by :
(a) smooth endoplasmic reticulum
(b) rough endoplasmic reticulum
(c) golgi apparatus
(d) plastids
Solution
(a) smooth endoplasmic reticulum
22. Cell arises from pre-existing cell was stated by :
(a) Haeckel
(b) Virchow
(c) Hooke
(d) Schleiden
Solution
(b) Virchow
23. Cell theory was given by :
(a) Schleiden and Schwann
(b) Virchow
(c) Hooke
(d) Haeckel
Solution
(a) Schleiden and Schwann
24. The only cell organelle seen in prokaryotic cell is :
(a) mitochondria
(b) ribosomes
(c) plastids
(d) lysosomes
Solution
(b) ribosomes
25. Organelle without a cell membrane is :
(a) ribosome
(b) Golgi apparatus
(c) chloroplast
(d) nucleus
Solution
(a) ribosome
26. 1μm is :
(a) 10–6 m
(b) 10–9 m
(c) 10–10 m
(d) 10–3 m
Solution
(a) 10–6 m
27. Lysosome arises from :
(a) endoplasmic reticulum
(b) Golgi apparatus
(c) nucleus
(d) mitochondria
Solution
(b) Golgi apparatus
28. Living cells were discovered by :
(a) Robert Hooke
(b) Purkinje
(c) Leeuwenhoek
(d) Robert Brown
Solution
(c) Leeuwenhoek
29. Select the odd one out
(a) The movement of water across a semipermeable membrane is affected by the amount of substances dissolved in it.
(b) Membranes are made of organic molecules like proteins and lipids.
(c) Molecules soluble in organic solvents can easily pass through the membrane.
(d) Plasma membranes contain chitin sugar in plants.
Solution
(d) Plasma membranes contain chitin sugar in plants.
Short Answer Questions for The Fundamental Unit of Life
30. Why are lysosomes known as ‘suicide-bags’ of a cell?
Solution
Lysosomes are known as suicide bags as they are membrane bound organelles which contains hydrolytic enzymes which have the capability to digest all organic components present and even unwanted cells. Lysosomes may burst and the digestive enzymes thus released digest their own cell.
31. Do you agree that “A cell is a building unit of an organism.” If yes, explain why?
Solution
Yes, cells are the building blocks of life. Every organism is made up of basic unit called cell. The different and special property of a cell helps the cell to form tissues, which further joins to form organs and transforms into a complete organism finally.
32. Why does the skin of your finger shrink when you wash clothes for a long time?
Solution
The skin of our finger shrinks when we wash clothes for a long time due to the process of osmosis. In this, the moisture present inside our fingers flows out due to the presence of hypertonic solution of detergent water. This causes our skin to shrink.
33. Why is endocytosis found in animals only?
Solution
The process where cells have to engulf the food and other substances from external environment is called endocytosis. This is because cell wall is absent in animals.
34. A person takes concentrated solution of salt, after sometime, he starts vomiting. What is the phenomenon responsible for such situation? Explain.
Solution
Concentrated salt solution causes irritation and excessive dehydration in the wall of alimentary canal due to exosmosis. There is uncomfortable stretching which causes reverse movements and result vomiting.
35. Name any cell organelle which is non-membranous.
Solution
Ribosome is cell organelle which is non-membranous.
36. We eat food composed of all the nutrients like carbohydrates, proteins, fats, vitamins, minerals and water. After digestion, these are absorbed in the form of glucose, amino acids, fatty acids, glycerol, etc. What mechanisms are involved in absorption of digested food and water?
Solution
Water is absorbed through the process of osmosis. Fatty acids and glycerol are diffused through submissive transport mechanism. Active transport helps in the absorption of glucose, amino acids and some ions.
37. If you are provided with some vegetables to cook, you generally add salt into the vegetables during cooking process. After adding salt, vegetables release water. What mechanism is responsible for this?
Solution
Vegetables release water (present in it) when salt is added due to the process of exosmosis.
38. If cells of onion peel and RBC are separately kept in hypotonic solution, what among the following will take place? Explain the reason for your answer.
(i) Both the cells will swell.
(ii) RBCs will burst easily while cells of onion peel will resist the bursting to some extent.
(iii) (i) and (ii) both are correct.
(iv) RBC and onion peel cells will behave similarly.
Solution
(ii) RBC cells will burst out due to osmosis in hypertonic solution, as they do not have cell wall. While in the onion peel cell, a counter pressure is opposite inside the cell against the direction of the entry of water after the cells become turgid. Due to this the further entry of water reduces.
39. Bacteria do not have chloroplast, but some bacteria are photoautotrophic in nature and perform photosynthesis. Which part of bacterial cell performs this?
Solution
These types of bacteria have photosynthetic pigments inside their vesicles attached to the plasma membrane, which helps in photosynthesis.
40. Match the following A and B :
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A |
B |
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(1) |
Smooth endoplasmic |
(a) |
Amoeba |
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(2) |
Lysosome |
(b) |
Nucleus |
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(3) |
Nucleoid |
(c) |
Bacteria |
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(4) |
Food vacuoles |
(d) |
Detoxification |
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(5) |
Chromatin material |
(e) |
Suicidal bags |
Solution
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A |
B |
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(1) |
Smooth endoplasmic |
(a) |
Amoeba |
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(2) |
Lysosome |
(b) |
Nucleus |
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(3) |
Nucleoid |
(c) |
Bacteria |
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(4) |
Food vacuoles |
(d) |
Detoxification |
|
(5) |
Chromatin material |
(e) |
Suicidal bags |
41. Write the name of different plant parts in which chromoplast, chloroplast and leucoplast are present.
Solution
(i) Chroinoplasts : flowers and fruits
(ii) Chloroplasts : green parts of plants (stems, leaves, etc.)
(iii) Leucoplasts : The covered underground parts (roots, stems, etc.)
42. Name the organelles which show the analogy written as under :
(a) Transporting channels of the cell _____
(b) Powerhouse of the cell _____
(c) Packaging and dispatching unit of the cell _____
(d) Digestive bag of the cell _____
(e) Storage sacs of the cell _____
(f) Kitchen of the cell _____
(g) Control room of the cell _____
Solution
(a) endoplasmic reticulum
(b) mitochondria
(c) golgi body
(d) lysosome
(e) vacuole
(f) chloroplast
(g) nucleus
43. How is a bacterial cell different from an onion peel cell?
Solution
The bacterial cells are the type of prokaryotic cells, but the onion peel cells come under plant cells
(eukaryotes).
44. How do substances like carbon dioxide (CO2) andwater (H2O) move in and out of the cell?
Solution
Diffusion helps in the gaseous exchange and due to the chemical concentration difference and osmosis helps for water movement.
45. How does amoeba obtain its food?
Solution
The process through which amoeba takes up food is called as endocytosis. It includes three different types of consumption depending upon the food particle. If solid then through phagocytosis, liquid food particles are taken up by pinocytosis and endocytosis depend on various receptors.
Endocytosis
46. Name the two organelles in a plant cell that contain their own genetic material and ribosomes.
Solution
Mitochondria and plastids.
47. Why are lysosomes also known as “scavengers of the cells”?
Solution Due to the properties of lysosomes like dead cell removals, cleaning the debris and indigestion of the unwanted particles through the digestive enzymes present in it, it is called “scavengers of the cells”.
48. Which cell organelle controls most of the activities of the cell?
Solution
Nucleus controls most of the activities of the cell.
49. Which kind of plastid is more common in :
(i) Roots of the plant?
(ii) Leaves of the plant?
(iii) Flowers and fruits of the plant?
Solution
(i) Leucoplasts
(ii) Chloroplasts
(iii) Chromoplasts
50. Why do plant cells possess large sized vacuole?
Solution
The membrane bound sacs found in cytoplasm of a plant cell is known as vacuole. It has many fusions :
(a) Its large size provides structural support.
(b) It helps in storage, waste disposal as well as protection.
(c) They also contain cell sap which provides cell turgidity.
51. How are chromatin, chromatid and chromosomes related to each other?
Solution
Chromatin can be seen in diffused network of fine filamentous structures and found only in a non dividing cell.
- Chromatin undergoes further condensation during the cell division to reproduce.
- Each chromosome contains two arms which consist of the alleles at various loci, known as chromatids.
52. What are the consequences of the following conditions?
(i) A cell containing higher water concentration than the surrounding medium.
(ii) A cell having low water concentration than the surrounding medium.
(iii) A cell having equal water concentration to its surrounding medium.
Solution
(i) Due to exosmosis, water will come out of the cell.
(ii) Endosmosis will pull water inside the cell.
(iii) This condition will have no effect on the cell.
Long Answer Questions for The Fundamental Unit of Life
53. Draw a plant cell and label the parts which :
(a) Determines the function and development of the cell.
(b) Packages materials coming from the endoplasmic reticulum.
(c) Provides resistance to microbes to withstand hypotonic external media without bursting.
(d) Is site for many biochemical reactions necessary to sustain life.
(e) Is a fluid contained inside the nucleus.
Solution
Following is the schematic diagram of plant cell containing the specific cell organelles as asked in the question :
(a) Nucleus
(b) Golgi apparatus
(c) Cell wall
(d) Cytoplasm
(e) Nucleoplasm
54. Draw a neat labelled diagram of an animal cell.
Solution
55. Draw a well labelled diagram of a eukaryotic nucleus. How is it different from nucleoid?
Solution
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Nucleus |
Nucleoid |
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1. |
Found in eukaryotic cell |
Found it prokaryotic cell |
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2. |
Nuclear membrane present |
Nuclear membrane absent |
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3. |
Large in size |
Small in size |
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4. |
Chromosome contains DNA |
Circular DNA is present. |
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5. |
Nucleoplasm and nucleolus are found. |
Nucleoplasm and nucleolus are absent |
56. Differentiate between rough and smooth endoplasmic reticulum. How is endoplasmic reticulum important for membrane biogenesis?
Solution
The differences between Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER) are as follows : 
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Smooth Endoplasmic Reticulum |
Rough Endoplasmic Reticulum |
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SER has no ribosomal particles on the surface, hence looks smooth. It helps in the manufacture of lipids and fat molecules. |
RER has particles of ribosomes on the surface, hence looks rough. Ribosome, are the site of protein synthesis. |
57. In brief state, what happens when :
(a) Dry apricots are left for sometime in pure water and later transferred to sugar solution?
(b) A Red Blood Cell is kept in concentrated saline solution?
(c) The Plasma-membrane of a cell breaks down?
(d) Rheo leaves are boiled in water first and then a drop of sugar syrup is put on it?
(e) Golgi apparatus is removed from the cell?
Solution
(a) Initially when water solution is kept, endosmosis take place. Later, due to the transfer of sugar solution, exosmosis take place and result is as a shrinkage of apricot.
(b) Concentrated saline medium will force the RBC to shrink and collapse due to exosmosis.
(c) The Plasma-membrane of a cell breaks down because of huge damage to the cell’s internal environment.
(d) The cells will be killed by boiling at high temperature and there would be no effect of addition of sugar syrup.
(e) Separate vesicles are formed with the help of Golgi apparatus. Hence, this will be influenced.
58. Draw a neat diagram of plant cell and label any three parts which differentiate it from animal cell.
Solution
