NCERT Class 9 Science Chapter 5 Solutions for Class 9 contains all the main and important topics which have a complete and detailed description. NCERT Class 9 Science Chapter 5 Solutions for Class 9 will help the students of class 9 to understand concepts.
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| NCERT Class 9 Science Chapter 5 Solutions |
NCERT Class 9 Science Chapter 5 Solutions
NCERT Class 9 Science Chapter 5 Solutions for Class 9 covers the complete syllabus. You can do your homework and
assignments with the help of NCERT
Solutions Class 9 Science chapter 5. This is very useful for the students who
are studying NCERT Science books.
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Table of Contents |
The students can
download the fundamental unit of life class 9 NCERT Solutions for Class 9 in
PDF format for offline use.
Before you study NCERT solutions of class 9 science chapter 5, You must go through the Overview class 9-chapter science solutions
Class 9 chapter science solutions Chapter Overview
1. What are Living Organisms Made Up of?
2. What is a Cell Made Up of? What is the Structural Organisation of a Cell?
i. Discovery of cell
ii. Cell theory
iii. Instruments for studying cell
iv. Shape and size of a cell
v. Plasma membrane or cell membrane
vi. Structure of cell membrane
vii. Functions of plasma membrane
viii. Transportation across the cell membrane
ix. Endocytosis and exocytosis
x. Cell wall
xi. Nucleus
xii. Cytoplasm
xiii. cytosol
xiv. Cell organelles
a. Endoplasmic reticulum(ER)
b. Golgi Apparatus
c. Lysosomes
d. Mitochondria
e. Plastids
f. Vacuoles
g. Centrosomes
So these are the main topic of class 9 chapter science solutions, you will have to read and
study. in this post, you have been provided ncert solutions of chapter 5.
Students of CBSE affiliated schools and, RBSE all other state boards can download fundamental unit of life class 9 NCERT solutions.
Class 9 Science Chapter 5 Questions- Answer
Intext Questions
NCERT Solutions
Class 9 Science Chapter 5 Page No. 59
Q.1 Who discovered the cell, and how?
Ans. Robert Hooke (1165) discovered the
cell. He examined a fine slice of a cork under a self-manufactured primitive
microscope. He observed that the slice of cork resembled the structure of a
honeycomb. These were actually dead cell walls observed by Robert Hooke. He
named these tiny compartment cellulae now termed cells.
Q.2 Why is the cell
called the structural and functional unit of life?
Ans. Cell is the structural unit of life
because; all living organisms are made up of cells. A cell is the functional unit of
life because functions of life like nutrition, respiration, excretion reproduction, etc. are performed by cells only.
NCERT Solutions Class 9 Science Chapter 5 Page No. 61
Q.1 How do substances
like CO2 and water move in
and out of the cell? Discuss.
Ans. Carbon dioxide (CO2)
moves in and out of the cells by the process of diffusion. In this
movement particles of various substances move from the region of the higher
concentration to the region of the lower concentration.
Water
moves in and out of the cells by osmosis. This is the movement of
water from the region of its higher concentration to the region of its lower
concentration through a semi-permeable membrane.
Q.2Why is a plasma
membrane called a selectively permeable membrane?
Ans. Plasma membrane allows the movement
of only selected molecules across it, so it is called a selectively permeable
membrane. For example, It allows the entry of gases through diffusion and water
through osmosis. Larger molecules may pass through the plasma membrane by an
active process. The plasma membrane is impermeable to certain other materials.
That’s why it is selectively permeable.
NCERT Solutions Class 9 Science Chapter 5 Page No. 63
Q.1 Fill in the gaps
in the following table illustrating differences between prokaryotic and
eukaryotic cells.
|
Prokaryotic Cell |
Eukaryotic Cell |
|
1. Size
: generally small (1-10 μm) 2. Nuclear
region ..................... and known as
....................................... 3. Chromosomes.
Single 4. Membrane-Bound cell organelles: Absent |
1. Size
: generally small (5-10 μm) 2. Nuclear
region is well defined surrounded by a nuclear membrane 3. Chromosomes.
more than one chromosome. |
Ans.
|
Prokaryotic
Cell |
Eukaryotic Cell |
|
1. Size
: generally small (1-10 μm) 2. Nuclear
region is poorly defined due to absence of nuclear membrane and known as nucleoid. 3. Chromosomes.
Single 4. Membrane
Bound cell organelles : Absent |
1. Size
: generally small (5-10 μm) 2. Nuclear
region well defined surrounded by a
nuclear membrane 3. Chromosomes.
More than one chromosome. 4. Membrane
bound cell organelles are present. |
NCERT Solutions Class 9 Science Chapter 5 Page No. 65
Q.1 Can you name the
two organelles, we have studied that contain their own genetic material?
Ans. Yes, mitochondria and chloroplast.
Q.2
If the
organisation of a cell is destroyed due to some physical or chemical influence,
what will happen?
Ans. If organisation is destroyed or
plasma membrane is disturbed the cell would not be able to maintain the
internal environment and chemical uniqueness. It will lead to the death of the
cell, Lysosomes would cause autolysis of the cell.
Q.3 Why are lysosomes
known as suicide bags?
Ans. Lysosomes are membrane-bound sacs
that contain hydrolytic enzymes. If lysosomes burst, enzymes are released and
digest other organelles of the same cell. Therefore, they are known as ‘suicide
bags’.
Q.4 Where are proteins
synthesised inside the cell?
Ans. Proteins are synthesized over the
ribosomes.
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NCERT Solutions Class 9 Science Chapter 5 exercise
Q.1 Make a comparison and write down ways in which plant cells are different from animal cells.
Ans.
Plant cell | Animal cell |
1.Plant cells have cell wall | 1.They don’t have a cell wall. |
2.They don’t have centriole. | 2.They have centriole. |
3.They have chloroplast. | 3.They don’t have chloroplast. |
4.Vacuole is very large and present in the centre of the cell. | 4.Small vacuole are present. |
5.Nucleus is present in the side of the cell. | 5.Nucleus is present in the centre of the cell. |
Q.2 How is a prokaryotic cell different from a eukaryotic cell?
Ans.
|
Prokaryotic
Cell |
Eukaryotic Cell |
|
1. Size
: generally small (1-10 μm) 2. Nuclear
region is poorly defined due to absence of nuclear membrane and known as nucleoid. 3. Chromosomes.
Single 4. Membrane
Bound cell organelles : Absent |
1. Size
: generally small (5-10 μm) 2. Nuclear
region well defined surrounded by a
nuclear membrane 3. Chromosomes.
More than one chromosome. 4. Membrane
bound cell organelles are present. |
Q.3 What would happen if the plasma membrane ruptures or breaks down?
Ans. If the plasma membrane ruptures or breaks down, the cell would not be able to maintain the internal environment and chemical uniqueness. It will lead to the death of the cell. Lysosomes would cause autolysis of the cell.
Q.4 What would happen to the life of a cell if there was no Golgi apparatus?
Ans. Golgi apparatus packages and dispatch enzymes, hormones, and other necessary lipids and proteins secreted by ER to target inside and outside of the cell.
The digestive enzymes which remain concealed in lysosome will remain free in the cytoplasm killing the other cell organelles. So in absence of Golgi apparatus cells would die.
Q.5 Which organelle is known as the powerhouse of the cell? Why?
Ans. Mitochondria are known as the powerhouse of the cell because the energy required for various life activities is released by mitochondria in the form of ATP molecules. Mitochondria contain enzymes that are needed for the oxidation of food present in the cells to CO2 and water. Oxidation of food releases energy which is used to form high-energy ATP molecules. ATP is known as the energy currency of the cell and these are used as cellular fuel.
Q.6 Where do the lipids and proteins constituting the cell membrane get synthesized?
Ans. Proteins are synthesized over ribosomes which are attached to the rough endoplasmic reticulum while lipids are synthesized over the smooth endoplasmic reticulum.
Q.7 How does an Amoeba obtain its food?
Ans. Amoeba is unicellular organism. It acquires its food by the process of endocytosis. The plasma membrane of the Amoeba is flexible which helps it to engulf food particles. Phagosome combines with a lysosome to produce digestive or food vacuole. Digestion occurs in the food vacuole. The digested food passes into the surrounding cytoplasm. The undigested residue is thrown out of the cell.
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| process of endocytosis |
Q.8 What is osmosis?
Ans. Osmosis: Osmosis is the process of Diffusion of water from the region of its higher concentration (pure water or dilute solution) to the region of its lower concentration through a semi-permeable membrane is called osmosis.
Q.9 Carry out the following osmosis experiment:
Take four peeled potato halves and hollow each one out to make potato cups. One of these potato cups should be made from boiled potatoes. Put each potato cup in through containing water. Now
(a) keep cup A empty.
(b) Put one teaspoon sugar in cup B
(c) Put one teaspoon salt in cup C
(d) Put one teaspoon sugar in a boiled potato cup D.
Keep this set up for two hours. Then observe the four potato cups and answer the following:
(i) Explain why water gathers in the hollowed portion of B and C.
(ii) Why is potato A necessary for this experiment.
(iii) Explain why water does not gather in the hollowed-out portions A and D.
Ans.(i) Water gathers in the hollowed portions B and C because the living plasma membrane of the potato cup acts as a semi-permeable membrane. There is a higher concentration of water in through than the sugar solution of B and salt solution of C potato cup respectively. So, by process of osmosis water moves into potato cups B and C.
(ii) Potato A functions as a control experiment which indicates that the cavity does not induce movement of water.
(iii) Water does not gather in potato cup A because it does not possess a higher osmotic concentration than the cell of potato.
Potato cup D is a boiled cup. It does not have a living cell and the membrane of the potato cells has lost its permeability. As a result, when a teaspoon of sugar is added into a hollowed portion of boiled potato cup D, water does not come out from within the potato cells intothehollowedprotein.
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| class 9 science chapter 5 Osmosis |
Important points of the fundamental unit of life class 9 NCERT solutions
1. All living forms are composed of small microscopic units called cells.
2. The fundamental organisational, functional unit of life is the cell.
3. The term ‘cell’ was given by Robert Hooke.
4. Cells are enclosed by a plasma membrane composed of lipids and proteins.
5. J.M. Schleiden and T. Schwann proposed the cell theory. Rudolf Virchow modified the cell theory and stated that every cell arises from pre-existing cells.
6. The cell membrane is an active part of the cell. It regulates the movement of materials between the ordered interior of the cell and the outer environment.
7. The living organisms who are made up of a single cell are called unicellular and those made up of more than one cell are called multicellular.
8. In plant cells, a cell wall proposed mainly of cellulose is located outside the cell membrane.
9. The presence of a cell wall enables the cells of plants, fungi, and bacteria to exist in hypotonic media without bursting.
10. Viruses’ are the exception to the cell theory.
11. The nucleus in eukaryotes is separated from the cytoplasm by a double-layered membrane and it directs the life processes of the cell.
12. In a prokaryotic cell, a well-organized nucleus is present and membrane-bound cell organelles are also absent – bacteria, blue-green algae.
13. The Endoplasmic reticulum is both a passageway for intracellular transport and as a manufacturing surface.
14. The Golgi apparatus consists of stacks of membrane-bound vesicles that function in the storage, modification, and packaging of substances manufactured in the cell.
15. A typical cell is bounded by a plasma membrane that has cytoplasm and genetic material.
16. Most plant cells have large membranous organelles called plastids which are of two types – chromoplasts and leucoplasts.
17. In a eukaryotic cell, a well-organized nucleus is present and membrane-bound cell organelles are present – plants, animals fungi, etc.
18. Chromoplasts that contain chlorophyll are called chloroplasts and they perform photosynthesis.
19. Plasma membrane is a living membrane. it provides shape and protection to the cell. It is called a selectively permeable membrane.
20. The primary function of leucoplasts is storage.
21. The diffusion of water through a semipermeable membrane from a region of higher concentration to the region of lower concentration is called Osmosis.
22. Most mature plant cells have a large vacuole that helps or maintains the turgidity of the cell and stores important substances including wastes.
23. When a cell is kept in a highly concentrated solution, it gets shrunk, this phenomenon is called Exo osmosis.
24. When a cell is kept in a dilute solution, it gets swelled, this phenomenon is called endo osmosis.
25. In plant cells a rigid cell wall is present which is composed of cellulose and present outside the cell membrane.
26. Cell wall provides a definite shape to the cell.
27. Cell wall protects plasma membrane and internal structures.
28. When a living plant cell losses water through osmosis, there is shrinkage or contraction of the contents of the cell away from the cell wall, this is known as plasmolysis.
29. Robert Brown discovered the nucleus in the cell.
30. Nucleus is the largest cell structure; it is spherical or oval in shape.
31. The nucleus is distinguished into- nucleoplasm, nuclear membrane, chromatin network, nucleolus.
32. The nucleus controls all metabolic activities of a cell, regulates the cell cycle.
33. The nucleus is concentrated with a chromatin network.
34. Cytoplasm is the fluid material present in the cell which is found in between plasma membrane and nuclear envelope.
35. Cytoplasm contains all cell organelles.
36. Endoplasmic reticulum provides internal support to the cytoplasm.
37. Rough endoplasmic reticulum helps in protein synthesis.
38. Smooth endoplasmic reticulum helps in lipid synthesis.
39. Golgi apparatus is made up cisternae, vacuole and saccule.it helps in the formation of cell plants and the synthesis of lysosomes.
40. Lysosomes are suicide bags.
41. Plastids are present only in plant cells and are of three types -chloroplast, chromoplast, and leucoplast.
42. Chloroplast take part in photosynthesis.
43. Vacuoles are involved in the maintenances of water balance.
44. Ribosomes are of two types 80s and 70s.
45. Ribosomes are the site of protein synthesis.
46. Centrosome helps in cell division in animal cells.
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Important Facts of Class 9 Science Chapter 5 NCERT Solutions
1. The smallest known cell is Mycoplasma gallisepticum which is 0.1 – 0.3 µ in diameter.
2. Largest cell is an egg of ostrich which is 170 ×135m.m. in size.
3. Acetabularia is the longest unicellular algae up to 10 c, long.
4. Longest plant cell is the fiber cell of manila hemp up to 100 cm in length.
5. Longest animal cell is a nerve cell up to 90 cm in length.
6. Term ‘Bio membrane’ was coined by Singer and Nicolson.
7. Prokaryotic cells and plant cells do not show endocytosis and exocytosis.
8. In a turgid cell DPD is minimum and is zero as osmotic pressure and turgor pressure are equal.
9. In plasmolysed cells DPD is maximum and is equal to osmotic pressure.
10. A plant cell composed of cellulose.
11. Bulk transport includes pinocytosis and phagocytosis.
12. The shrunken state of RBCs caused by exosmosis is called crenation.
13. Nucleus is considered as the brain of the cell.
14. Hofineister discovered chromosomes.
15. Term ‘Chromosome’ was given by Waldayer.
16. Nucleus is the largest component of a cell.
17. A plant Haplopappus gracilis contains a minimum chromosomes number.
18. An animal ascaris megalocephala has a minimum number of chromosomes.
19. Maximum number of chromosomes in a plant cell found in Ophioglossuim.
20. Maximum number of chromosomes in an animal cell found in Aulacantha.
21. Human RBCs lack of nucleus.
Important Terms related to NCERT Solutions Class 9 Chapter 5 Science
1. Cristae – The fold of the inner membrane of mitochondria.
2. Grana – Thylakoids packed like piles of coins.
3. Acellular – Single-celled organisms are known as Acellular.
4. Algae – A group of aquatic plants which lack root, stem, and leaves and perform photosynthesis.
5. Plasmodesmata – Fine cytoplasmic strands interconnecting adjacent cells in plants.
6. Thylakoids – Flattened disc-like membranous structure in the stroma of the chloroplast.
7. Bacteria – Group of prokaryotic organisms except for blue green algae.
8. Chromosomes- Thread-like structure having genetic material made up of chromatin.
9. Centromere – Region of chromosomes at which spindle fibril is attached during cell division.
10. Chromatin - Thin thread-like structure found in the region of the nucleoplasm.
11. Autolysis - Process of self-destruction of the cell by the release of lysosomal enzymes in the cell.
12. Chromatid – during cell division each chromosome consists of two identical halves and each half is called a chromatid.
13. Gene – A unit of genetic information that transfers hereditary characters.
14. Cilium – A minute hair-like structure that is found on the surface of the cell and helps in the movement of the cell.
15. Microvilli- Electron microscopic evaginations of the plasma membrane of some cells.
16. Cytology – The study of various aspects of cells and their organelles is called cytology.
17. Hydrolysis – Cleavage of a molecule with water into two or smaller molecules.
18. Diffusion – Movement of molecules from a region of higher concentration to a region of lower concentration.
19. Tonoplast – Vacuolar membrane
20. Crenation – when an animal cell is placed in a hypertonic solution, it shrinks on all sides to give a wrinkled appearance the phenomenon is known as crenation.
21. Mesosomes - Infolds of the plasma membrane found in the bacteria cell.
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Oral questions of class 9-chapter 5 science solutions
Question -1-Who discovered the cell?
Answer-Rohbert Berown
Question -2- Who invented the electron microscope/
Answer-Knoll and Ruska
Question -3-Which instrument is used to observe the cellular organisation of living beings?
Answer-Microscope
Question -4-What is the exception of cell theory?
Answer-viruses
Question -5-what is the source of light in an electron microscope?
Answer-Beam of electrons
Question -6-Who called protoplasm the physical basis of life?
Answer-Huxley
Question -7-Who Propose cell theory?
Answer-Schleiden and Schwann
Question -8-When did Robert Hook discover cell?
Answer- In 1665
Question -9- What term did Robert Hooke give to cell
Answer-Celluae
Question -10-Name the red colour bearing plastids.
Answer-Chromoplast
Question -11-What is the location of the nucleus in animal cells?
Answer-In animals nucleus is located in the center.
Question -12-Name the smallest cell?
Answer-Pleuro Pneumonia like an organism
Question -13-Name two prokaryotic cells.
Answer- Bacteria and cyanobacteria
Question -14-Name the longest plant cell.
Answer-Acetabularia
Question -15-What is phagocytosis?
Answer-The process of intake of solid particles by a cell through the plasma membrane.
Question -16-What will happen to a cell if it is placed in hypertonic solutions?
Answer-The cell will shrink
Question -17-Where do the red-colored plastids occur in plants?
Answer-These plastids occur in flowers and fruits
Question -18-Name the component which is present in plant cells but absent in animal cells.
Answer-Plastids
Question -19- Who coined the term ‘Protoplasm’ for a living matter?
Answer-E.J.purkinge
Question -20-Name any two Eukaryotic organisms
Answer-Amoeba and Mouse
Suggested Topics of The Fundamental Unit of Life Solutions
You are suggested some important topics of chapter 5 science class 9 NCERT solutions for your better preparation for upcoming examinations so prepare notes on them.
1. Difference between prokaryotic cell and eukaryotic cell
2. Difference between plant cell and animal cell
3. Functions of plasma membrane
4 . Nucleus – its structure and functions
5. Endoplasmic reticulum- Types, structure, and functions
6. Lysosomes
7. Mitochondria- structure and functions
8. Plastids
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Frequently Asked questions
1. What is the main function of plasma membrane class 9 ncert?
The plasma membrane defines the boundary of the cell and regulates the flow of substances into and out of the cell.
2. What are mitochondria Class 9?
Mitochondria are the powerhouse of a cell. The energy required for different functions for life is released or produced by mitochondria.
3. What is cell class 9 ncert?
The cell is the fundamental and structural unit of life. A cell contains different cell organelles. A cell performs different kinds of functions.
4. What is the fundamental unit of life class 9?
In class 9th chapter 5 is the fundamental unit of life. A cell is known as a fundamental and structural unit of life.
5. what is endoplasmic reticulum class 9?
The endoplasmic reticulum is a complex network of membrane-bound channels or sheets, tubules, and vessels.
Remedial Education Point.com provides you complete study material for class 9 absolutely free. Now you can get accurate NCERT Class 9 Science Chapter 5 Solutions prepared by our expert teachers.
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