NEET BIOLOGY

Detailed explanation-1: -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-2: -With increasing cell growth, cancer cells spread or infiltrate to involve other organs, displacing normal tissue and severely depleting nutrient and metabolic resources, which results in death either from cancer cachexia or from mechanical disruption of normal organ function.

Detailed explanation-3: -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-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.

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.