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Cell : The Unit of Life

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12
Mention the differences between pili and fimbriae.



1. These are elongate tubular structures.

2. They are present mainly in Gram -ve bacteria.

3. They are involved in mating process and form conjugation tube.

4. These are not responsible in connecting cells.

1. These are small bristle like fibres.

2. They are present both in Gram +ve and Gram -ve bacteria.

3. They have no role in mating.

4. These are responsible for connecting cells.


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

Mathias Schleiden.

State one difference between gram positive and gram negative bacteria.

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

 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. 

What is the function of contractile vacuole in amoeba?


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

Theodore Schwann