Question

? A cell that accumulates lots of mutational damage to its DNA may escape the normal controls of the cell cycle and become ____________________.

Answer 1

Ans : Cancer cells

Conversion of a normal cells into cancer cell is called oncogenesis. It involves ;

Transformation in which growth restriction is removed.

Repeated division.

Ability to metastatize new areas.

Nonmaturation

Change in cytoplasm and nucleus.

Noninhibition of growth even due to cell to cell contact.

Rous found a virus to cause cancer ( Rous sarcoma virus). Some more viruses were later associated with different types of cancers.

However, till now no human cancer is known definitely to be due to any virus.Actually in human beings cancer is caused by different type of mutations are described as follows ---

1.chromosome translocation

2. Extra - activation of certain genes

3. Jumping gene/ transposons

4. Amplification or depletion of certain genes etc