NCERT Solutions for Class 9 Science Unit 5

The Fundamental Unit of Life Class 9

Unit 5 The Fundamental Unit of Life Exercise Solutions

A cell is capable of independent existence and can carry out all the functions which are necessary for a living being. A cell carries out nutrition, respiration, excretion, transportation and reproduction; the way an individual organism does. Unicellular organisms are capable of independent existence which shows a cell's capability to exist independently. Due to this, a cell is called the fundamental and structural unit of life. All living beings are composed of the basic unit of life, i.e. cell.
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Question : Solutions of Questions on Page Number : 59

Q1 :  

Who discovered cells and how?


Answer :

Cells were discovered in 1665 by an English Botanist, Robert Hooke. He used a primitive microscope to observe cells in a cork slice.

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Q2 :  

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


Answer :

Cells constitute various components of plants and animals. A cell is the smallest unit of life and is capable of all living functions. Cells are the building blocks of life. This is the reason why cells are referred to as the basic structural and functional units of life. All cells vary in their shape, size, and activity they perform. In fact, the shape and size of the cell is related to the specific functions they perform.

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Q3 :  

How do substances like CO2and water move in and out of the cell? Discuss.


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Q4 :  

Why is the plasma membrane called a selectively permeable membrane?


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Q5 :  

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) 1 µm== 10-6 m

1.

Size: generally large (5-100 µm)

2.

Nuclear region: _____________________________ and is known as ________.

2.

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

3.

Chromosome: single

3.

More than one chromosome

4.

Membrane-bound cell organelles are absent

4.

________________________________________________________________________________________________


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Q6 :  

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


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Q7 :  

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


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Q8 :  

Why are lysosomes known as suicide bags?


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Q9 :  

Where are proteins synthesized inside the cell?


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Exercise : Solutions of Questions on Page Number : 66

Q1 :  

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


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Q2 :  

How is a prokaryotic cell different from a eukaryotic cell?


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Q3 :  

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


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Q4 :  

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


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Q5 :  

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


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Q6 :  

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


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Q7 :  

How does anAmoebaobtain its food?


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Q8 :  

What is osmosis?


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Q9 :  

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 sugar in cup B

(c) Put one teaspoon salt in cup C

(d) Put one teaspoon 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.

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

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


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<< Previous Chapter 4 : Structure of the Atom Next Chapter 6 : Tissues >>

Science : CBSE NCERT Exercise Solutions for Class 9th for The Fundamental Unit of Life will be available online in PDF book form soon. The solutions are absolutely Free. Soon you will be able to download the solutions.

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