EVERYDAY SCIENCE

Detailed explanation-1: -Conclusion. 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-2: -Mutations in particular genes may mean that: a cell starts making too many proteins that trigger a cell to divide. a cell stops making proteins that normally tell a cell to stop dividing. abnormal proteins may be produced that work differently to normal.

Detailed explanation-3: -Carcinogenesis can be divided conceptually into four steps: tumor initiation, tumor promotion, malignant conversion, and tumor progression (Figure 17-1).

Detailed explanation-4: -DNA repair genes are involved in fixing damaged DNA. Cells with mutations in these genes tend to develop additional mutations in other genes and changes in their chromosomes, such as duplications and deletions of chromosome parts. Together, these mutations may cause the cells to become cancerous.