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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
Describe eukaryotic nucleus.

Nucleus is the control unit of cell. It was discovered by Robert Brown in 1831. The nucleus is found in all eukaryotic cells exceptin mature RBCs and sieve tubes. It is covered by a nuclear membrane which consists of two parallel membrane, The space between the two membrane is called perinuclear space. The nuclear membrane has pores and controls the transfer of material in and out of the nucleus. The nucleoplasm or the matrix inside the nucleus consists of dense spherical bodies called nucleolus. The nucleplus houses the chromatin. nucleolus is the site for active protein synthesis. The chromatin contains the DNA, histone and non-histone protein and RNA. The chromatin becomes dense during interphase of the cell division.



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

Theodore Schwann 

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

Mathias Schleiden.

What is the function of contractile vacuole in amoeba?


 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.