[Campbell Biology P.437] Tumor-suppressor genes play a critical role in preventing uncontrol... | Practice Question
Tumor-suppressor genes play a critical role in preventing uncontrolled cell growth. What is their primary normal function, and how does a mutation that decreases their activity contribute to cancer?
A: Their normal function is to promote cell division; a mutation decreasing their activity leads to a halt in cell division.
B: Their normal function is to inhibit cell division; a mutation decreasing their activity leads to uncontrolled cell growth.
C: Their normal function is to repair damaged DNA; a mutation decreasing their activity primarily impairs cell adhesion.
D: Their normal function is to initiate apoptosis; a mutation decreasing their activity leads to increased cell senescence.
Explanation
According to the text, tumor-suppressor genes' normal products inhibit cell division and prevent uncontrolled cell growth. A mutation that decreases their normal activity contributes to cancer by stimulating growth through the absence of suppression.