AP BIOLOGY

Detailed explanation-1: -These changes are also called genetic changes. A DNA change can cause genes involved in normal cell growth to become oncogenes. Unlike normal genes, oncogenes cannot be turned off, so they cause uncontrolled cell growth. In normal cells, tumor suppressor genes prevent cancer by slowing or stopping cell growth.

Detailed explanation-2: -Cancer is unchecked cell growth. Mutations in genes can cause cancer by accelerating cell division rates or inhibiting normal controls on the system, such as cell cycle arrest or programmed cell death.

Detailed explanation-3: -Oncogenes may cause normal cells to become cancer cells and grow in the body. Mutations that lead to the conversion of proto-oncogenes to oncogenes usually occur during a person’s lifetime and are not inherited from a parent.

Detailed explanation-4: -Before an oncogene becomes mutated, it is called a proto-oncogene, and it plays a role in regulating normal cell division. Cancer can arise when a proto-oncogene is mutated, changing it into an oncogene and causing the cell to divide and multiply uncontrollably.

Detailed explanation-5: -Summary. Two classes of genes, oncogenes and tumor suppressor genes, link cell cycle control to tumor formation and development. Oncogenes in their proto-oncogene state drive the cell cycle forward, allowing cells to proceed from one cell cycle stage to the next.