Question

Normal (nonmutant) tumor-suppressor genes often function:

a) as negative regulators of cell division.

b) in the maintenance of genome integrity.

c) in the stimulation of cell division.

d) as both a and b.

Answer 1

Tumor suppressor genes are crucial for regulating cell division and maintaining genome integrity by acting as negative regulators, preventing uncontrolled cell proliferation. Mutations in these genes can lead to cancer as the cell's normal braking mechanism is compromised.

Step-by-step explanation:

The primary function of tumor suppressor genes is to regulate cell growth and division. These genes code for proteins that serve as negative regulators of cell division, essentially acting as the brakes for the cell cycle. When tumor suppressor genes function properly, they can prevent a cell from undergoing uncontrolled division, which is critical in the prevention of cancer. However, if there is a mutation in these genes, they may fail to stop the cell cycle, leading to abnormal cell proliferation and potentially resulting in cancer. Tumor suppressor genes like p53, Rb, and p21 are essential for maintaining genome integrity by putting up roadblocks to cell-cycle progression until certain events are completed. They are the cellular equivalent of a vehicle's brakes, and malfunctioning tumor suppressor genes can contribute to the development of cancer, similar to how faulty brakes can lead to a car crash.