NCERT Exemplar Class 9 Science Chapter 5 The Fundamental Unit of Life Solutions
NCERT Exemplar Solutions for Class 9 Science Chapter 5 The Fundamental Unit of Life covers all the important questions and answers as well as advanced level questions. It helps in learning about the structure of units that make living organisms, unicellular organisms, multicellular organisms, Structure of a cell, cell organelles, plasma membrane, nucleus and cytoplasm.
The NCERT Exemplar solutions for class 9 science is very important in the examination. NCERT Exemplar Solutions for Class 9 Science Chapter 5 The Fundamental Unit of Life is provided by our experts. They prepared the best solutions which help the students in understanding the solutions in an easy way. This chapters also covers the other topics like rough Endoplasmic reticulum (RER), smooth Endoplasmic reticulum (SER), lysosomes, vacuoles, bacteria, fungi, plastids, chromoplasts, chloroplasts and leucoplast.
Chapter Name | Chapter 5 The Fundamental Unit of Life |
Book Title | NCERT Exemplar for Class 9 Science |
Related Study |
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Topics Covered |
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NCERT Exemplar Solutions for Chapter 5 The Fundamental Unit of Life Class 9 Science
Multiple Choice Questions
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
Viruses are considered to be intermediates between living and non-living. This is because they cannot metabolize or reproduce on their own. Moreover, virus requires a host for all its processes. Viruses can be stored as crystal like chemicals. Virus crystals are collection of millions of virus cells.
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.
The water from the surrounding enter the cell through osmosis and the cell swells up when the concentration of water molecules in surrounding medium is higher.
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)
Proteins are produced in ribosomes. Enzymes are proteins. Hormones and starch are not produced in ribosome.
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.
Energy is produced in the mitochondria.
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
Living plant cell loses water through the process of osmosis. This results in shrinking or contraction of the contents of the cell away from the cell wall. This is known as plasmolysis. When a plant cell has more water content than the surrounding, the plant cell tends to transfer water to its surroundings.
8. Which of the following are covered by a single membrane?
(a) Mitochondria
(b) Vacuole
(c) Lysosome
(d) Plastid
Solution
(b) Vacuole, (c) Lysosome
Both (b) and (c)
Both vacuole and lysosome are single membrane bound cell organelles. Mitochondria and plastids are double membrane bound cell organelles
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.
Golgi apparatus has a role in the storage and synthesis of certain biomolecules. It does not have any role in the synthesis of lysosome.
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).
RER has ribosomes present on its surface. These ribosomes are responsible for the synthesis of proteins and enzymes.
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
SER plays an important role in detoxifying many poisons and drugs in the liver cells of vertebrates.
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
Endoplasmic reticulum plays important role in the production of both lipids and proteins. SER produces proteins and RER produces lipids.
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
Golgi apparatus is involved in the packaging and transport of many biomolecules such as proteins, lipids and carbohydrates.
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
Vacuoles are responsible for storage, turgidity and rigidity of the cell and waste excretion. Locomotion is carried out by specialised organelles present outside cytoplasm. Vacuoles are present inside the cytoplasm.
16. Amoeba acquires its food through a process, termed :
(a) exocytosis
(b) endocytosis
(c) plasmolysis
(d) exocytosis and endocytosis both
Solution
(b) endocytosis
The process of taking in of matter by a living cell by invagination of its membrane to form a vacuole is known as endocytosis. In endocytosis, substances that are external to a cell are brought into the cell.
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
Hydrilla, mango tree and cactus are plants and thus their cell wall is made up of cellulose. The cell wall of bacteria is made of polysaccharide.
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
Mitochondria and chloroplast are the organelles that have separate DNA called as mitochondrial DNA and chloroplast DNA.
20. Kitchen of the cell is :
(a) mitochondria
(b) endoplasmic reticulum
(c) chloroplast
(d) golgi apparatus
Solution
(c) chloroplast
Food in plants is produced inside 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
The cell theory which stated that all plants and animals are made up of cell and cell is the basic unit of life was proposed by 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
Golgi bodies, chloroplast and nucleus are all membrane bound organelles but ribosomes are organelles without membrane.
26. 1μm is :
(a) 10–6 m
(b) 10–9 m
(c) 10–10 m
(d) 10–3 m
Solution
(a) 10–6 m
10–3 m–millimetre
10–6 m –Micrometer
10–9 m –nanometer
27. Lysosome arises from :
(a) endoplasmic reticulum
(b) Golgi apparatus
(c) nucleus
(d) mitochondria
Solution
(b) Golgi apparatus
The main functions of golgi apparatus are secretion, packaging and modification of proteins. It is also involved in the synthesis of new membranes and lysosomes.28. Living cells were discovered by :
(a) Robert Hooke
(b) Purkinje
(c) Leeuwenhoek
(d) Robert Brown
Solution
(c) Leeuwenhoek
Robert hook observed cells first but he observed the dead cork cell. It was Leeuwenhoek who observed living cell from his microscope.
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.
Plant plasma membrane contains cellulose in it.
Short Answer Questions
30. Why are lysosomes known as ‘suicide-bags’ of a cell?
Solution
Lysosomes have digestive enzymes. When it bursts, the digestive enzymes are released and it starts digesting its own cells. This is the reason why lysosomes are known as suicidal bags of a cell.
31. Do you agree that “A cell is a building unit of an organism.” If yes, explain why?
Solution
Yes, the cells are the building units of an organism. Cells which perform similar functions join together to form tissues which further forms organs and organ systems.
This forms an organism. In a unicellular organism, a single cell performs all the life processes.
32. Why does the skin of your finger shrink when you wash clothes for a long time?
Solution
Soap solution is hypertonic in nature. This makes the water move out of the cells which in turn result in shrinking of fingers when you wash clothes for a long time.
33. Why is endocytosis found in animals only?
Solution
As cell wall is absent in animals, endocytosis is found only in animals. Because of this the movement of substances inside the cell is easier in animals than in plants.
34. A person takes concentrated solution of salt, after sometime, he starts vomiting. What is the phenomenon responsible for such situation? Explain.
Solution
Upon consumption of concentrated salt solution, the process of osmosis process takes place which results in dehydration. This is the reason why a person vomits.
35. Name any cell organelle which is non-membranous.
Solution
The only non-membranous cell organelle is the ribosome.
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
Diffusion and osmosis are involved in absorption and digestion respectively. 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 on adding salt due to the process of osmosis. The addition of salt makes the external environment hypertonic. That is the concentration of water outside is lowered as compared to the concentration of water inside the cell. This results in the elimination of water from the vegetables due to 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
The hypotonic water surrounding the cell moves inside the cell. This leads to swelling of the cells. As RBCs do not have plasma membrane, they swell and burst easily. Plant cells have cell wall which prevents them from bursting.
39. Bacteria do not have chloroplast, but some bacteria are photoautotrophic in nature and perform photosynthesis. Which part of bacterial cell performs this?
Solution
Small vesicles associated with plasma membrane are present in bacteria. These vesicles have pigment which can trap sunlight to carry photosynthesis.
40. Match the following A and B :
A | B | ||
(1) | Smooth endoplasmic | (a) | Amoeba |
(2) | Lysosome | (b) | Nucleus |
(3) | Nucleoid | (c) | Bacteria |
(4) | Food vacuoles | (d) | Detoxification |
(5) | Chromatin material | (e) | Suicidal bags |
Solution
A | B | ||
(1) | Smooth endoplasmic | (a) | Amoeba |
(2) | Lysosome | (b) | Nucleus |
(3) | Nucleoid | (c) | Bacteria |
(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
- Chromoplast is present in flower and fruit.
- Chloroplast is found in the leaves.
- Leucoplast is present in the roots.
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
|
Bacterial cell |
Onion peel cell |
|
Prokaryotic cell |
Eukaryotic cell |
|
Lack of organized nucleus, the genetic material present in the form of nucleoid |
Well-organised Nucleus |
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Nuclear membrane absent |
Nuclear membrane present |
|
Only a single chromosome is present |
More than one chromosome are present |
|
Membrane-bound organelles absent |
Membrane-bound organelles present |
|
Nucleolus is absent |
Nucleolus is present |
|
Cell division takes place by fission or budding |
Cell division takes place by mitosis or meiosis |
44. How do substances like carbon dioxide (CO2) and water (H2O) move in and out of the cell?
Solution
Carbon dioxide (CO2) moves in and out of the cell by the process of diffusion and water (H2O) move in and out of the cell through osmosis.
45. How does amoeba obtain its food?
Solution
Amoeba obtains its food through the process of endocytosis. Amoeba has finger-like projections which fuse with the food particles to forma food vacuole. Inside the vacuole the complex food particles are broken down into simpler ones which are then diffused into the cytoplasm.
46. Name the two organelles in a plant cell that contain their own genetic material and ribosomes.
Solution
The two organelles in a plant cell that contain their own genetic material and ribosomes are chloroplast and mitochondria.
47. Why are lysosomes also known as “scavengers of the cells”?
Solution
Lysosomes have lytic enzymes which are used to destroy the pathogens and worn-out cells. Lysosomes also destroy waste materials which are harmful for the cell. This is the reason why Lysosomes also are known as “scavengers of the cells”.
48. Which cell organelle controls most of the activities of the cell?
Solution
Most of the activities of the cell are controlled by the nucleus.
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 are more common in roots of the plant.
(ii) Chloroplasts are more common in leaves of the plant.
(iii) Chromoplasts are more common in flowers and fruits.
50. Why do plant cells possess large sized vacuole?
Solution
Vacuoles not only store important material but they also contain a sap that gives turgidity to the cell, this is the reason why plant cells possess large-sized vacuole.
51. How are chromatin, chromatid and chromosomes related to each other?
Solution
- Chromatin is a thread-like structure which forms chromosomes.
- A copy of duplicated chromosome which is generally joined to the other copy by a centromere is called Chromatid.
- When a cell starts to divide, the tangled mass of chromatin condenses into long threads and finally, rod-like bodies called chromosomes.
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) The cell loses water and shrinks if it contains higher water concentration than the surrounding medium. This is known as exosmosis.
(ii)The cell bursts if it has a lower water concentration than the surrounding medium. This process is known as endosmosis.
(iii) There is no change in the cell if a cell having equal water concentration to its surrounding medium.
Long Answer Questions
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 determines the function and development of the cell.
(b) Golgi apparatus is the package material coming from the endoplasmic reticulum.
(c) Cell wall provides the resistance to microbes to withstand hypotonic external media without bursting.
(d) Cytoplasm is a site for many biochemical reactions necessary to sustain life.
(e) Nucleoplasm is a fluid contained inside the nucleus.
54. Illustrate only a plant cell as seen under electron microscope. How is it different from animal cell?
Solution
|
Plant Cell |
Animal Cell |
|
Cell wall present |
Cell wall absent |
|
It has a large vacuole |
It has a small vacuole |
|
Plastids are present |
Plastids are absent |
|
Centriole absent |
Centriole present |
55. Draw a neat labelled diagram of an animal cell.
Solution
56. Draw a well labelled diagram of a eukaryotic nucleus. How is it different from nucleoid?
Solution
|
Nucleus |
Nucleiod |
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A membrane-bound organelle in the cytoplasm of eukaryotes. |
A particular area in the cytoplasm of eukaryotes. |
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Contains more than one chromosome. |
Contains a single chromosome. |
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Well-organized structure |
Poorly organized structure |
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Spherical shaped |
Irregular shaped |
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Nucleolus and nucleoplasm present |
Nucleolus and nucleoplasm absent |
57. Differentiate between rough and smooth endoplasmic reticulum. How is endoplasmic reticulum important for membrane biogenesis?
Solution
Differences between Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER):
|
Rough endoplasmic reticulum |
Smooth endoplasmic reticulum |
|
It possesses ribosomes attached to the membrane. |
It does not possess ribosomes attached to its membrane. |
|
Found deep inside the cytoplasm. |
Found on the periphery. |
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Involved in protein synthesis. |
Involved in lipid synthesis. |
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May develop from the nucleus. |
May develop from the rough endoplasmic reticulum. |
58. 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) When we put few dried raisins or apricots in plain water and leave them for some time, the cell gains water and swells. If we put the same seeds in a concentrated sugar solution, the seeds lose water, and consequently shrink.
(b) The red blood cells lose water when kept in concentrated saline solution and shrink consequently.
(c) The cell dies when the plasma membrane of a cell breaks down.
(d) The cells of rheo leaves are dead on boiling. If we put sugar solution on the dead leaves, there will be no intake of water due to lack of osmosis. Here the cell undergoes plasmolysis. This concludes that only living cells undergo osmosis.
(e) Removal of golgi apparatus stops the formation of vesicles and transport of proteins and lipids.
58. Draw a neat diagram of plant cell and label any three parts which differentiate it from animal cell.
Solution
