• School
  • Engineering and Architecture
  • Management and Business Administration
  • Medicine and Allied Sciences
  • Law
  • Animation and Design
  • Media, Mass Communication and Journalism
  • Finance & Accounts
  • Computer Application and IT
  • Pharmacy
  • Hospitality and Tourism
  • Competition
  • Study Abroad
  • Arts, Commerce & Sciences
  • Learn
  • Online Courses and Certifications
NCERT Solutions For Class 9 Science Chapter 5 - The Fundamental Unit Of Life

NCERT Solutions For Class 9 Science Chapter 5 - The Fundamental Unit Of Life

Irshad AnwarUpdated on 20 Sep 2025, 03:44 PM IST

The NCERT Solutions for Class 9 Science Chapter 5 - The Fundamental Unit of Life explain that everything living is made of cells. Cells are the basic and fundamental units of life that keep a living being alive. In this chapter, students learn what cells are, how they were first discovered, and why they are important for each organism. The NCERT Solutions break down the difficult topics in simple steps and make things easier to understand.

This Story also Contains

  1. Download The Fundamental Unit of Life NCERT Solutions PDF
  2. Access Class 9 Science Chapter 5 - The Fundamental Unit of Life Solutions (In-text Exercise)
  3. Get Class 9 Science Chapter 5 - The Fundamental Unit of Life Solutions (Chapter-end Exercise)
  4. Approach to Solve The Fundamental Unit of Life Class 9 Question Answer
  5. Important Topics of Class 9 NCERT Science Chapter 5
  6. Important Question from NCERT Class 9 Science Chapter 5
  7. What will You Learn From The Fundamental Unit of Life NCERT Solutions
  8. NCERT Solutions for Class 9 Science Chapter-wise
NCERT Solutions For Class 9 Science Chapter 5 - The Fundamental Unit Of Life
NCERT Solutions for Class 9 Science Chapter 5 The Fundamental Unit of Life

The Fundamental Unit of Life class 9 question answer explains how cells grow and divide. Processes like mitosis and meiosis are explained, which are needed for growth and reproduction. The role of the plasma membrane is also explained in simple steps. Students can also download the Fundamental Unit of Life NCERT PDF, which follows the NCERT guidelines, to study in a simple and organised way. Doing studies in an organised way builds a strong foundation for higher classes.

Download The Fundamental Unit of Life NCERT Solutions PDF

Students can download the complete questions with detailed answers in a PDF for better learning. The Class 9 Science Chapter 5 - The Fundamental Unit of Life question answer explores various topics that form the base of biology. The NCERT Solutions for Class 9 improve performance and boost confidence.

Download PDF

Also Read,

Access Class 9 Science Chapter 5 - The Fundamental Unit of Life Solutions (In-text Exercise)

The detailed answers to all the questions in this chapter are given below. Studying the Class 9 Science Chapter 5 - The Fundamental Unit of Life solutions will help to understand how cells are discovered.

Topic 5.1 - What are Living Organisms made up of?

Ques. 1. Who discovered cells, and how?

Answer:

Cells were discovered in 1665 by Robert Hooke. He was examining a thin slice of cork using a compound microscope designed by him. He saw that the structure of the cork at a microscopic level is similar to that of a honeycomb. It had several small chambers like those in a honeycomb.

These small chambers were termed cells.

Ques. 2. Why is the cell called the structural and functional unit of life?

Answer:

The cell is called the structural and functional unit of life, as it is the smallest living unit that can carry out all the living processes essential for living.

Topic 5.2 What is a cell made up of? What is the structural organisation of the cell?

Ques. 1. How do substances like CO2 and water move in and out of the cell? Discuss

Answer:

CO2 and water move in and out of the cell through the cell membrane. CO2 moves by diffusion, and water moves by osmosis, which is the diffusion of water through a selectively permeable membrane.

Ques. 2. Why is the plasma membrane called a selectively permeable membrane?

Answer:

The plasma membrane is called a selectively permeable membrane because it allows the movement of certain substances from the inside of the cell to the outside and vice versa. This membrane also restricts the movement of some substances. This selectivity depends on the requirements of the cell and the substances present in the surroundings of the cell.

Topic 5.2.2 Cell Wall

Ques. 1. Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.

Prokaryotic Cell

Eukaryotic Cell

Size: Generally small (1-10μm)

1μm=10-6m

Size: Generally large (5-100μm)

Nuclear region: ..................................

.......................and known as......

Nuclear region: well-defined and surrounded by a nuclear membrane

Chromosome: single

More than one chromosome

Membrane-bound cell organelles are absent

...................................................................

...............................................................

....................................

Answer:

Prokaryotic Cell

Eukaryotic Cell

1. Size is generally small.

1. Size is generally large.

2. Nuclear Region: poorly defined (nucleoid), no nuclear membrane

2. Nuclear Region: well-defined, surrounded by nuclear membrane

3. Chromosome: single.

3. More than one chromosome.

4. Membrane-bound cell organelles are absent

4. Membrane-bound cell organelles are present.

Topic 5.2 What is a cell made up of? What is the structural organisation of the cell?

Ques. 1. Can you name the two organelles we have studied that contain their own genetic material?

Answer:

Two organelles that contain their genetic material are

1. Mitochondria

2. Chloroplasts (A type of Plastid)

Ques. 2. If the organisation of a cell is destroyed due to some physical or chemical influence, what will happen?

Answer:

If the organisation of a cell is destroyed due to some physical or chemical influence, it will not be able to perform the life processes important for living, and may undergo self-digestion by lysosomes.

Ques. 3. Why are lysosomes known as suicide bags?

Answer:

When the cells are damaged to such an extent that they are incapable of performing certain functions that are essential for survival, the organism tries to get rid of these cells.

For this function, the lysosomes, which are membrane-bound organelles, burst and release hydrolytic enzymes called hydrolases, which destroy the cell, and lysosomes are therefore called suicide bags.

Ques. 4. Where are proteins synthesised inside the cell?

Answer:

  • Inside the cells, the proteins are synthesised at sites called ribosomes.

  • These are very small structures made up of ribonucleic acids and proteins.

Get Class 9 Science Chapter 5 - The Fundamental Unit of Life Solutions (Chapter-end Exercise)

All the detailed answers to the questions given at the end of the chapter are given below. The Fundamental Unit of Life class 9 question answer forms the base of many topics in science for higher classes.

Ques1. Make a comparison and write down ways in which plant cells are different from animal cells.

Answer:

Plant Cells

Animal Cells

1. Plant cells are generally bigger than animal cells.

1. Animal cells are relatively small.

2. Plant cells have a cell wall.

2. Animal cells do not have a cell wall.

3. The nucleus is pushed to the periphery due to a large central vacuole.

3. The nucleus is at the centre of the cell.

4. Large central vacuole.

4. Small or multiple vacuoles.

5. Chloroplast is present.

5. Chloroplast is absent.

Ques 2. How is a prokaryotic cell different from an eukaryotic cell?

Answer:

Prokaryotic Cell

Eukaryotic Cell

1. A prokaryotic cell is quite small in size. (1-10 μm)

1. A eukaryotic cell is relatively larger.

(5-100 μm)

2. The nuclear region is poorly defined as the nuclear membrane is absent.

2. The nuclear membrane is present, and the nuclear region is well defined.

3. Organelles are not membrane-bound.

3. Organelles are membrane-bound.

4. Only one chromosome is present.

4. More than one chromosome is present.

Ques 3. What would happen if the plasma membrane ruptured or broke down?

Answer:

  • If the plasma membrane ruptures, the cell would eventually die because the movement of substances wouldn't be regulated.

  • This will cause important substances to move out of the cell and harmful substances from the environment to enter the cell.

Ques 4. What would happen to the life of a cell if there were no Golgi apparatus?

Answer:

  • The Golgi apparatus stores and transports materials through vesicles.

  • In the absence of the Golgi apparatus, these functions would stop, and this would cause the death of the cell.

Ques 5. Which organelle is known as the powerhouse of the cell? Why?

Answer:

Mitochondria are known as the powerhouse of the cell, as they release energy in the form of ATP, which is essential for performing all the functions of the cell.

Ques 6. Where do the lipids and proteins constituting the cell membrane get synthesised?

Answer :

  • Lipids and proteins are synthesised in the endoplasmic reticulum.

  • In the Rough Endoplasmic Reticulum, proteins are manufactured, whereas the manufacturing of lipids takes place in the Smooth Endoplasmic Reticulum.

Ques 7. How does an Amoeba obtain its food?

Answer:

  • Amoeba obtains its food through the flexibility of its shape.

  • An amoeba obtains its food by engulfing food particles with its cell membrane, forming a food vacuole. This process is called phagocytosis, a type of endocytosis.

Ques 8. What is osmosis?

Answer:

Osmosis is the movement of water from a region of high water concentration (low solute concentration) to a region of low water concentration (high solute concentration) through a semipermeable membrane.

Ques 9. (i) Carry out the following osmosis experiment:

Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,

(a) Keep cup A empty

(b) Put one teaspoon of sugar in cup B

(c) Put one teaspoon of salt in cup C

(d) Put one teaspoon of sugar in the boiled potato cup D. Keep these for two hours. Then, observe the four potato cups and answer the following:

(e) Explain why water gathers in the hollowed portion of B and C.

Answer:

(i) Due to the presence of a solute (sugar in the case of B and salt in the case of C), there is a concentration difference of water in the potato cup and the trough, due to which osmosis takes place where the cells of the potato act as the semi-permeable membrane.

Ques 9. (ii) Carry out the following osmosis experiment:

Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,

(a) Keep cup A empty

(b) Put one teaspoon of sugar in cup B

(c) Put one teaspoon of salt in cup C

(d) Put one teaspoon of sugar in the boiled potato cup D.

Keep these for two hours. Then, observe the four potato cups and answer the following:

(ii) Why is potato A necessary for this experiment?

Answer:

Potato A is necessary because it acts as the control for the experiment. Without A, we will have no reference to compare the other cases with.

Ques 9.(iii) Carry out the following osmosis experiment:

Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,

(a) Keep cup A empty

(b) Put one teaspoon of sugar in cup B

(c) Put one teaspoon of salt in cup C

(d) Put one teaspoon of sugar in the boiled potato cup D.

Keep these for two hours. Then observe the four potato cups and answer the following:

(iii) Explain why water does not gather in the hollowed-out portions of A and D.

Answer:

Since there is no solute in the hollow part of potato A, no osmosis has taken place, and water does not gather in the hollowed part of A.

In the case of D, even after the presence of solute, osmosis does not take place. Boiling this potato has destroyed the cells, and thus, no semipermeable membrane is present for osmosis to take place.

Ques 10. Which type of cell division is required for the growth and repair of the body and which type is involved in the formation of gametes?

Answer:

Mitosis is required for the growth and repair of the body, and meiosis is involved in the formation of gametes.

Approach to Solve The Fundamental Unit of Life Class 9 Question Answer

Given below are a few important tips that students can follow to solve the questions effectively.

  • Students should begin by understanding the structure and functions of different cell organelles. It includes the nucleus, mitochondria, Golgi apparatus, and Endoplasmic Reticulum (ER).

  • Focus should be laid on the difference between plant and animal cells. Students can take help from the Class 9 Science Chapter 5 - The Fundamental Unit of Life question answer.

  • Having neat, labelled diagrams of plant and animal cells will improve visual learning. The Class 9 Science Chapter 5 - The Fundamental Unit of Life solutions have all the well-labeled diagrams.

  • Students are advised to make short notes by highlighting the important terms.

  • Solving questions from the NCERT Solutions for Class 9 Science will improve understanding.

Also, check the NCERT Books and the NCERT Syllabus here:

Important Topics of Class 9 NCERT Science Chapter 5

Important topics and subtopics of this chapter are listed below. Questions are frequently asked about these topics in the exam. To gain clarity, students can refer to the NCERT Solutions for Class 9 Science Chapter 5 - The Fundamental Unit of Life.

Important Question from NCERT Class 9 Science Chapter 5

Below is the solved practice question along with the answer. Practicing questions is important to understand the pattern and difficulty level. The NCERT Solutions for Class 9 Science Chapter 5 - The Fundamental Unit of Life includes different forms of questions along with the detailed answers.

Q1. Vacuoles maintain the turgidity in plant cells.

Options:

(1) True

(2) False

Explanation:

Vacuoles are large, fluid-filled organelles found in plant cells and play an important role in maintaining the structure and rigidity of the cell. When the vacuole is filled with water, it creates a state that keeps the plant upright and firm. This pressure prevents the plant from wilting and maintains its shape.

Therefore, the correct answer is Option (1) True.

What will You Learn From The Fundamental Unit of Life NCERT Solutions

Cells are the basic structural and functional units of all living organisms. This chapter explains their importance and how they work together to support life.

  • Students will understand the concept of the cell and its discovery with the help of The Fundamental Unit of Life NCERT Solutions.

  • They will learn about different cell organelles and their functions, along with the diagrams.

  • The solutions explain the differences between plant and animal cells in a simple way.

  • With the Fundamental Unit of Life class 9 question answer, learners can understand important diagrams like cell structure.

  • They will know how the process of mitosis and meiosis takes place, by which cells divide and grow.

NCERT Solutions for Class 9 Science Chapter-wise

Below are the chapter-wise solutions:

Frequently Asked Questions (FAQs)

Q: What is the structure of a plant cell?
A:

A plant cell has a cell wall, cell membrane, nucleus, cytoplasm, mitochondria, chloroplasts, vacuole, Golgi apparatus, ribosomes, and endoplasmic reticulum. All these organelles maintain functions such as photosynthesis, storage, and structural support.

Q: What are the main differences between plant and animal cells?​
A:

Plant cells contain a cell wall, chloroplasts, and a large vacuole, while animal cells do not have these but contain centrioles and lysosomes. Plant cells are stiff, owing to the cell wall, whereas animal cells are elastic. All the differences are well-explained in the NCERT Solutions for Class 9 Science Chapter 5 The Fundamental Unit of Life. 

Q: What is a cell?
A:

A cell is a fundamental structural and functional unit of life as explained in the NCERT Solutions for Class 9 Science Chapter 5 The Fundamental Unit of Life. It performs fundamental biological functions, and it exists both in unicellular and multicellular organisms with organelles to carry out functions of various lives.

Q: How do cell organelles contribute to cellular functions?​
A:

Cell organelles perform specialized functions: mitochondria produce energy, the nucleus controls activities, the Golgi apparatus processes proteins, and the endoplasmic reticulum aids transport. Together, they maintain cellular structure and function.

Q: What is the significance of the cell membrane and cell wall?
A:

The cell membrane controls movement of materials into and out of the cell to ensure homeostasis. The cell wall (in plants) gives support, protection, and shape to cells, keeping from taking too much water.

Articles
Upcoming School Exams
Assam High School Leaving Certificate Examination
Ongoing Dates
Assam HSLC Application Date

1 Sep'25 - 4 Oct'25 (Online)

Maharashtra Higher Secondary School Certificate Examination
Ongoing Dates
Maharashtra HSC Board Application Date

8 Sep'25 - 30 Sep'25 (Online)

Popular Questions

A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

 Option 2)

0.16\; J
Option 3)

1.00\; J

 Option 4)

0.67\; J
Read Complete Answer

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

 Option 2)

 6.45×10−3 kg
Option 3)

 9.89×10−3 kg

 Option 4)

12.89×10−3 kg

 
Read Complete Answer

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

 Option 2)

200 \, \, J - 500 \, \, J
Option 3)

2\times 10^{5}J-3\times 10^{5}J

 Option 4)

20,000 \, \, J - 50,000 \, \, J
Read Complete Answer

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

 Option 2)

\; K\;
Option 3)

zero\;

 Option 4)

K/4
Read Complete Answer

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

 Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced
Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

 Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .
Read Complete Answer

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

 Option 2)

3.125 × 10-2
Option 3)

1.25 × 10-2

 Option 4)

2.5 × 10-2
Read Complete Answer

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

 Option 2)

increase two fold
Option 3)

remain unchanged

 Option 4)

be a function of the molecular mass of the substance.
Read Complete Answer

With increase of temperature, which of these changes?

Option 1)

Molality

 Option 2)

Weight fraction of solute
Option 3)

Fraction of solute present in water

 Option 4)

Mole fraction.
Read Complete Answer

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

 Option 2)

6.023 × 1022
Option 3)

half that in 8 g He

 Option 4)

558.5 × 6.023 × 1023
Read Complete Answer

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

 Option 2)

more than 3 but less than 6
Option 3)

more than 6 but less than 9

 Option 4)

more than 9
Read Complete Answer

Courses After 12th

Applications for Admissions are open.

NEET Most scoring concepts
Get now

This ebook serves as a valuable study guide for NEET 2025 exam.

NEET Previous 10 Year Questions
Get now

This e-book offers NEET PYQ and serves as an indispensable NEET study material.

JEE Main Important Physics formulas
Get now

As per latest syllabus. Physics formulas, equations, & laws of class 11 & 12th chapters

JEE Main Important Chemistry formulas
Get now

As per latest syllabus. Chemistry formulas, equations, & laws of class 11 & 12th chapters

JEE Main high scoring chapters and topics
Get now

As per latest 2024 syllabus. Study 40% syllabus and score upto 100% marks in JEE

JEE Main Important Mathematics Formulas
Get now

As per latest syllabus. Maths formulas, equations, & theorems of class 11 & 12th chapters

View all Application Forms

News and Notifications

Latest updates