AP BIOLOGY

Detailed explanation-1: -Most cancer-causing DNA changes occur in sections of DNA called genes. 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.

Detailed explanation-2: -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-3: -An oncogene is a mutated gene that has the potential to cause cancer. Before an oncogene becomes mutated, it is called a proto-oncogene, and it plays a role in regulating normal cell division.

Detailed explanation-4: -Three genetic mechanisms activate oncogenes in human neoplasms: (1) mutation, (2) gene amplification, and (3) chromosome rearrangements.

Detailed explanation-5: -Gene changes within cells (mutations) Sometimes a change happens in the genes when a cell divides. This is a mutation. It means that a gene has been damaged or lost or copied too many times. Mutations can happen by chance when a cell is dividing.