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Cell : The Unit of Life

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Biology

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Biology

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12
Distinguish between primary cell wall and secondary cell wall.

Primary cell wall

Secondary cell wall

1. It is found in young dividing cells.

2. It lies internal to the middle lamella.

3. It is present in all plant cells.

4. It is elastic and capable of expansion in a growing cell.

5. It is thin.

6. It is composed of mainly cellulose and lacks additional material.

1. It is found in a mature and non dividing cell.

2. It lies internal to the primary wall.

3. It is present in certain cells only.

4. It is rigid and incapable of expansion.

5. It is thick.

6. It has additional materials like hemi-cellulose lignin, suberin etc.

 

Who concluded, “Cells are the ultimate units forming the structure of all plant tissues”?

Mathias Schleiden.

What is the function of contractile vacuole in amoeba?

Excretion.

State one difference between gram positive and gram negative bacteria.

Gram positive bacteria retains the gram stain whereas the Gram negative bacteria does not. 

Who reported that the cell had an outer layer which is known as plasma membrane today?

Theodore Schwann 

 What are receptor molecules ?

Receptor molecules are specific proteins in the cell's plasma membrane that receive chemical signals from outside the cell. When such chemical signals bind to a receptor, they cause some form of cellular response.