AP BIOLOGY

Detailed explanation-1: -Scientists call this process apoptosis. In cancer cells, the molecules that decide whether a cell should repair itself are faulty. For example, a protein called p53 usually checks if the cell can repair its genes, or if the cell should die.

Detailed explanation-2: -Telomerase is also abnormally active in most tumors. The enzyme allows tumor cells to maintain long telomeres and divide uncontrollably. Telomerase activity was thought to be turned off in most of the body’s other cells.

Detailed explanation-3: -Mutated genes don’t work properly because the instructions in their DNA get mixed up. This can cause cells that should be resting to divide and grow out of control, which can lead to cancer.

Detailed explanation-4: -Cancer is the result of unchecked cell division caused by a breakdown of the mechanisms regulating the cell cycle. The loss of control begins with a change in the DNA sequence of a gene that codes for one of the regulatory molecules. Faulty instructions lead to a protein that does not function as it should.