Chapter 5: The Fundamental Unit of Life Short Questions | science Class 9 CBSE

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Chapter 5: The Fundamental Unit of Life Short Questions | science Class 9 CBSE | ByteNotes.in

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Question 1

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Q1. Who discovered the cell?

Robert Hooke in 1665.
He observed cork under microscope.
Coined the term 'cell'.

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Question 2

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Q2. What is the function of the plasma membrane?

Controls entry and exit of substances.
Provides protection and support.
Performs osmosis and diffusion.

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Question 3

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Q3. Define osmosis.

Movement of water through a selectively permeable membrane.
From lower to higher solute concentration.
Important for cellular water balance.

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Question 4

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Q4. What is plasmolysis?

Shrinkage of cytoplasm due to water loss.
Occurs in hypertonic solutions.
Demonstrates osmosis.

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Question 5

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Q5. Name two cell organelles with their own DNA.

Mitochondria.
Chloroplast.
They replicate independently.

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Question 6

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Q6. What are ribosomes?

Small structures for protein synthesis.
Found in cytoplasm and on RER.
Not membrane-bound.

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Question 7

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Q7. Write one function each of SER and RER.

SER: Synthesizes lipids.
RER: Helps in protein synthesis.
Part of endomembrane system.

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Question 8

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Q8. What is the function of lysosomes?

Digest worn-out organelles.
Destroy harmful substances.
Help in cell clean-up.

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Question 9

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Q9. Write any two differences between plant and animal cells.

Plant cells have cell wall; animal cells don’t.
Plant cells have chloroplasts; animal cells don’t.
Vacuoles are larger in plant cells.

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Question 10

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Q10. What is cytoplasm?

Fluid inside the cell membrane.
Contains organelles.
Site of various biochemical reactions.

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Chapter sections

Chapter 5: The Fundamental Unit of Life | Short Questions

Q1. Who discovered the cell?

Q2. What is the function of the plasma membrane?

Q3. Define osmosis.

Q4. What is plasmolysis?

Q5. Name two cell organelles with their own DNA.

Q6. What are ribosomes?

Q7. Write one function each of SER and RER.

Q8. What is the function of lysosomes?

Q9. Write any two differences between plant and animal cells.

Q10. What is cytoplasm?