AP BIOLOGY

Detailed explanation-1: -Cancer is a disease in which some of the body’s cells grow uncontrollably. There are many different types of cancer, and each begins when a single cell acquires a genomic change (or mutation) that allows the cell to divide and multiply unchecked. Additional mutations can cause the cancer to spread to other sites.

Detailed explanation-2: -Cancer is a disease caused when cells divide uncontrollably and spread into surrounding tissues. Cancer is caused by changes to DNA. Most cancer-causing DNA changes occur in sections of DNA called genes. These changes are also called genetic changes.

Detailed explanation-3: -In cancer, the cells often reproduce very quickly and don’t have a chance to mature. Because the cells aren’t mature, they don’t work properly. And because they divide quicker than usual, there’s a higher chance that they will pick up more mistakes in their genes.

Detailed explanation-4: -DNA replication errors, especially those occurring at regions that are hard to replicate, called fragile sites, can cause breaks in DNA. This can lead to cancer, primarily by making it more likely that fragments of chromosomes rearrange themselves, activating genes that lead to uncontrollable cell division.

Detailed explanation-5: -Cancer is essentially a disease of mitosis-the normal ‘checkpoints’ regulating mitosis are ignored or overridden by the cancer cell. Cancer begins when a single cell is transformed, or converted from a normal cell to a cancer cell.