AP BIOLOGY

Detailed explanation-1: -Genes that normally block cell cycle progression are known as tumor suppressors. Tumor suppressors prevent the formation of cancerous tumors when they are working correctly, and tumors may form when they mutate so they no longer work.

Detailed explanation-2: -Tumor suppressor genes are normal genes that slow down cell division or tell cells to die at the right time (a process known as apoptosis or programmed cell death).

Detailed explanation-3: -Tumor suppressor genes are genes that code for the negative regulator proteins, the type of regulator that-when activated-can prevent the cell from undergoing uncontrolled division.

Detailed explanation-4: -A tumor suppressor gene is a segment of DNA that codes for one of the negative cell cycle regulators. If that gene becomes mutated so that the protein product becomes less active, the cell cycle will run unchecked.

Detailed explanation-5: -Tumor suppressor genes, active in normal cells, work to prevent uncontrolled cell growth. Proto-oncogenes, which are positive cell-cycle regulators, can become oncogenes and cause cancer when mutated.