NCERT Solutions For Class 9 Science Chapter 5 - The Fundamental Unit Of Life
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
- Download The Fundamental Unit of Life Class 9 Questions and Answers PDF
- Access Class 9 Science Chapter 5 The Fundamental Unit of Life Question Answer (In-text Exercise)
- Get Class 9 Science The Fundamental Unit of Life Question Answer (Chapter-end Exercise)
- Approach to Solve Chapter 5 The Fundamental Unit of Life Question Answer
- Important Topics of Class 9 NCERT Science Chapter 5
- Important Questions from NCERT Class 9 Science Chapter 5
- What will You Learn From The Fundamental Unit of Life NCERT Solutions?
- Why Class 9 Science Chapter 5 The Fundamental Unit of Life NCERT Solutions are Important?
- NCERT Solutions for Class 9 Science Chapter-wise
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. Doing studies in an organised way builds a strong foundation for higher classes. Students can also download the Fundamental Unit of Life Class 9 questions and answers PDF, which follows the NCERT guidelines, to study in a simple and organised way.
Download The Fundamental Unit of Life Class 9 Questions and Answers PDF
Students can download the complete questions with detailed answers in a PDF for better learning. The Fundamental Unit of Life Class 9 questions and answers PDF explores various topics that form the base of biology. The NCERT Solutions for Class 9 improve performance and boost confidence.
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Access Class 9 Science Chapter 5 The Fundamental Unit of Life Question Answer (In-text Exercise)
The detailed answers to all the questions in this chapter are given below. Studying the NCERT Solutions Class 9 Science Chapter 5 The Fundamental Unit of Life 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 organization 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
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)
Answer:
If the organization 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 synthesized inside the cell?
Answer:
Inside the cells, the proteins are synthesized at sites called ribosomes.
These are very small structures made up of ribonucleic acids and proteins.
Get Class 9 Science The Fundamental Unit of Life Question Answer (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 synthesized 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.
Answer:
Mitosis is required for the growth and repair of the body, and meiosis is involved in the formation of gametes.
Approach to Solve Chapter 5 The Fundamental Unit of Life 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.
Students are advised to make short notes by highlighting the important terms.
Having neat, labeled diagrams of plant and animal cells will improve visual learning. The Fundamental Unit of Life Class 9 question answer have all the well-labeled diagrams.
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 Questions 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.
Question 1: 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.
Question 2: What are the structures performing different functions in the cell called?
Options
(1) Organs
(2) Organelles
(3) Cytoplasm
(4) Cell membrane
Explanation:
All the functions of the cell are assigned to different structures of the cell, such as mitochondria, endoplasmic reticulum, Golgi apparatus, etc. These are called organelles of the cell.
Therefore, the correct answer is option (2) Organelles.
Question 3: What is the role of chromoplasts?
Options
(1) Production of energy
(2) Production of food
(3) Digestion of foreign particles
(4) None of the above
Explanation:
The role of chromoplasts is to absorb sunlight and use it to trap the energy in the form of food molecules by the process of photosynthesis.
Therefore, the correct answer is option (2), Production of food
Question 4: Vacuoles are absent in:
Options
(1) Plants
(2) Animals
(3) Microorganisms
(4) None of the above
Explanation:
Vacuoles are present in plants, animals, and even some microorganisms, though their size and function may vary. In plants, vacuoles are large and central, in animals, they are small and temporary, and in certain microorganisms, vacuole-like structures help store food or water.
Therefore, the correct answer is option (4), None of the above
Question 5: Lysosomes are used to store nutrients it.
Options:
(1) True
(2) False
Explanation:
Lysosomes contain digestive enzymes that help in the digestion of foreign materials.
Therefore, the correct answer is option (2) False.
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 Class 9 question answer.
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.
They will know how the process of mitosis and meiosis takes place, by which cells divide and grow.
With Class 9 Science The Fundamental Unit of Life question answer, learners can understand important diagrams like cell structure.
Why Class 9 Science Chapter 5 The Fundamental Unit of Life NCERT Solutions are Important?
Cells are the building blocks of all living organisms. The Fundamental Unit of Life chapter explains the structure and functions of cell organelles, the difference between plant and animal cells, and other concepts.
Students learn about the structure and function of cell organelles such as the nucleus, mitochondria, chloroplasts, and more.
Class 9 Science Chapter 5 The Fundamental Unit of Life NCERT Solutions explains the differences between plant and animal cells.
Knowledge of the Fundamental Unit of Life chapter forms the base for Class 11 and 12 topics in Cell Biology and Molecular Biology.
The chapter introduces the concept of cell theory, which is a very important concept in all biology studies.
Questions related to cell organelles and cell theory are frequently asked in the NEET and other competitive exams.
NCERT Solutions for Class 9 Science Chapter-wise
Below are the chapter-wise solutions that help students understand concepts, practice questions, and prepare effectively for exams.
NCERT Solutions for Class 9 Chapter 1 Matter in Our Surroundings |
NCERT Solutions for Class 9 Chapter 2 Is Matter Around Us Pure |
NCERT Solutions for Class 9 Chapter 5 The Fundamental Unit of Life |
NCERT Solutions for Class 9 Chapter 8 Force and Laws of Motion |
NCERT Solutions for Class 9 Chapter 12 Improvement in Food Resources |
Frequently Asked Questions (FAQs)
Q: What is the function of the nucleus?
A:
The nucleus oversees cellular processes through the regulation of gene expression. DNA is present in the nucleus, which stores genetic information, and the nucleolus, which synthesises ribosomes required for protein synthesis.
Q: What is the role of the cell membrane?
A:
The cell membrane defends the cell and controls the movement of nutrients, gases, and waste. It is semi-permeable and performs selective transport of molecules without disturbing the internal environment.
Q: How can students easily understand the concepts of chapter The Fundamental Unit of Life?
A:
Students can understand the concepts better by reading NCERT explanations carefully, revising diagrams, and practicing questions regularly to strengthen their basics.
Q: Is the chapter Fundamental Unit of Life important for higher studies?
A:
Yes, this chapter is very important for higher studies as it forms the foundation for understanding advanced topics in biology such as genetics, human physiology, and biotechnology.
Q: What is a cell?
A:
A cell is a fundamental structural and functional 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 life stages.
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 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.
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