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 : You will learn everything in this chapter that you need to know about the cell and its structure. Aakash Institute provides the solutions of this chapter. Solutions are carefully crafted by highly qualified science teachers who are experts in their respective fields.

Furthermore, we guarantee that the appropriate content solution, Aakash also provides a complete breakdown of the questions. The solutions provide detailing all the steps and processes in an easy-to-understand manner. Additionally, we guarantee that the solutions we provide are tailored to meet multiple criteria for scoring marks.

A cell is capable of independent existence. It is known to carry out all the functions which are essential to life in a being. A cell carries out the responsibilities in nutrition, respiration, excretion, transportation, and reproduction. The process of the cell forms the basis of the process as it is for an individual organism. Unicellular organisms are capable of independent existence. The above reasons are enough to prove a cell being the fundamental and structural unit of life. The cells of various types make up all the living beings. This chapter also talks about cells in different organisms, like plant cells, animal cells, and cytoplasm. Students will also study the difference between plant and animal cells along with structure and function of cytoplasm in class 9 chapter 5. 

• Robert Hooke became the first man to discover a cell in 1665.
• Leeuwenhoek was the first to discover free-living cells in pond water in 1674.
• Robert Brown discovered the nucleus in 1831.
• Purkinje coined the term protoplasm in 1839.

NCERT Solutions for Class 9 Science Chapter 5 The Fundamental Unit of Life

Q1. Who discovered cells, and how?
Answer: Cells were discovered in 1665 by Robert Hooke. He was examining a thin slice of cork using a primitive microscope designed by himself. 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 as cells.

Q2. 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 which 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?

Q1. How do substances like and water move in and out of the cell? Discuss
Answer: CO 2 and water move in and out of the cell through the cell membrane by the process of diffusion and osmosis respectively.

Q2. Why is the plasma membrane called a selectively permeable membrane?
Answer: The plasma membrane is called a selectively permeable membrane because it relatively allows the movement of substances from the inside of the cell to the outside and vice- versa.

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

Q1. Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.

Answer:

CBSE NCERT solutions for class 9 science chapter 5 The fundamental unit of life

Q1. Can you name the two organelles we have studied that contain their own genetic material?

Answer: Two organelles which contain their own genetic material are

1. Mitochondria
2. Plastids

Q2. If the organization of a cell is destroyed due to some physical or chemical influence, what will happen?

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 essential for living and therefore would be digested by lysozymes.

Q3. 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 which are essentials for survival, the organism tries to get rid of these cells.

For this function, the lysosomes which are membrane-bound organelles burst and release digestive enzymes called lysozymes which destruct the cell and lysosomes are therefore called suicide bags.

Q4. 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.

NCERT Solutions for Class 9 science Chapter 5 The Fundamental Unit of Life: Solved Exercise Solutions

Q1. Make a comparison and write down ways in which plant cells are different from animal cells.

Answer:

Q2. How is a prokaryotic cell different from a eukaryotic cell?

Answer:

Q3. What would happen if the plasma membrane ruptures or breaks down?

Answer:

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

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

 Q4. What would happen to the life of a cell if there was no Golgi apparatus?

Answer:

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.

Q5. Which organelle is known as the powerhouse of the cell? Why?

Answer:

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

Q6. Where do the lipids and proteins constituting the cell membrane get synthesized?

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.

Q7. How does an Amoeba obtain its food?

Answer:

Amoeba obtains its food by the virtue of the flexibility of its shape.

Amoeba entraps the food particle around its membrane and then engulfs it within the cytoplasm. This process is called endocytosis.

Q8. What is osmosis?

Answer:

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

Q9. (i) Carry out the following osmosis experiment:

Take four peeled potato halves and scoops 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 sugar in cup B 

(c) Put one teaspoon 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:

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

Answer:

(i) Due to the presence of a solute (sugar in case of B and salt in 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.

Q9. (ii) Carry out the following osmosis experiment:

Take four peeled potato halves and scoops 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 sugar in cup B

(c) Put one teaspoon 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 absolutely necessary because it acts as the control for the experiment. Without A we will have no reference to compare the other cases with. We can see that since there is no solute in the hollow part of this potato no osmosis has taken place. 

Q9.(iii) Carry out the following osmosis experiment:

Take four peeled potato halves and scooPs 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 sugar in cup B 

(c) Put one teaspoon 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 semi-permeable membrane is there for osmosis to take place.

Q10. Which type of cell division is required for growth and repair of the body and which type is involved in the formation of gametes? 

Answer:

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

The Fundamental Unit of Life Important Questions and Answers

Q1. What is the fundamental unit of life class 9 science chapter 5?
Answer: The fundamental unit of life is the cell. This chapter in Class 9 explains the structure, functions, and importance of cells, which make up all living organisms.

Q2. What is the answer to the fundamental unit of life?
Answer: The answer to the fundamental unit of life is the cell. Cells are the smallest units that perform all necessary functions for life, making them the building blocks of all living beings.

Q3. What is the structural and functional unit of life class 9?
Answer: The cell is known as the structural and functional unit of life. It forms the structure of organisms and performs essential functions like respiration, digestion, and reproduction.

Q4. What is the cell in class 9th?
Answer: In Class 9th, a cell is defined as the smallest unit of life that forms the structure of living organisms and carries out all life processes. It can be either simple, like in unicellular organisms, or complex, as in multicellular organisms

Q5. Who discovered the cell?
Answer: The cell was discovered by Robert Hooke in 1665. He observed cells for the first time while examining a slice of cork under a simple microscope.