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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
What are the characteristics of prokaryotic cells?

Characteristics of Prokaryotic cell are as follows:

1. The nucleus is not bounded by a membrane.

2. Their genetic material is naked and present in the form of nucleoid in the cytoplasm.

3. They are generally smaller and divide more rapidly as compared to the eukaryotic cell.

4. They are usually surrounded by cell wall except for mycoplasma.

5. Besides genomic DNA many prokaryotic cell have small circular DNA called plasmids outside the genomic DNA.

6. Eukaryotic organelles or membrane bound organelles are not found in the prokaryotic cells. The ribosomes found in these are of 70S type. 

7. Mesosomes which are the invaginations of plasma membrane may be present.

8. They have special inclusion bodies. 




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. 

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

Theodore Schwann 

What is the function of contractile vacuole in amoeba?