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NCERT solutions Science Class 9 chapter 5 The Fundamental Unit of Life


NCERT Science Class 9

Science Textbook for Class 9

Chapter 5 - The Fundamental Unit of Life

Page 59

Who discovered cells and how?

Q 1 | Page 59

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

Q 2 | Page 59

Page 60

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

Q 1 | Page 60

Why is the plasma membrane called a selectively permeable membrane?

Q 2 | Page 60

Page 63

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 Size: generally large (5-100 µm)
2. Nuclear region: ______________and is known as____ Nuclear region: well-defined and surrounded by a nuclear membrane
3. Chromosome: single More than one chromosome
4. Membrane-bound cell organelles are absent  _______________________________
Q 1 | Page 63

Page 65

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

Q 1 | Page 65

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

Q 2 | Page 65

Why are lysosomes known as suicide bags?

Q 3 | Page 65

Where are proteins synthesized inside the cell?

Q 4 | Page 65

Pages 66 - 67

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

Q 1 | Page 66

How is a prokaryotic cell different from a eukaryotic cell?

Q 2 | Page 66

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

Q 3 | Page 66

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

Q 4 | Page 67

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

Q 5 | Page 67

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

Q 6 | Page 67

How does an Amoeba obtain its food?

Q 7 | Page 67

What is osmosis?

Q 8 | Page 67

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.

Q 9 | Page 67

NCERT Science Class 9

Science Textbook for Class 9