Question

Which of the following is a consequence of inactivation of both p53 alleles in a cell?

a) Reduction of p21 synthesis
b) Programmed cell death (apoptosis) of the cell
c) A reduction in kinase activity of the cyclin-Cdk complex
d) Relative instability of the non-functional protein

Answer 1

Inactivation of both p53 alleles results in a reduction of p21 synthesis, leading to a compromised G1 checkpoint and potentially contributing to tumor growth due to unregulated cell division.

Step-by-step explanation:

The inactivation of both p53 alleles in a cell has significant consequences for the regulation of the cell cycle. One major consequence is a reduction of p21 synthesis, which acts as an inhibitor for the Cdk/cyclin complexes. Without p53 to upregulate p21, Cdk activation is not effectively blocked, leading to a compromised G1 checkpoint and continuation of the cell cycle regardless of DNA damage. Consequently, this dysregulation can contribute to tumor growth, as damaged cells may continue to divide without appropriate controls in place.