Question

Phosphorylated p53 is stable and active, being able to bind to regulatory region of p21 gene, promoting the gene expression of p21, a Cdk-cyclin inhibitor and prevents cell cycle from continuing

Answer 1

p53 is a multi-functional protein that halts the cell cycle in response to damaged DNA and triggers repair mechanisms or apoptosis. p21, produced by p53, inhibits the activity of Cdk/cyclin complexes, preventing cell cycle progression.

Step-by-step explanation:

p53 is a multi-functional protein that plays a major role in regulating the cell cycle. When p53 detects damaged DNA during the G1 phase of the cell cycle, it halts the cell cycle and recruits enzymes to repair the DNA. If repair is not possible, p53 can trigger apoptosis, or cell death, to prevent the duplication of damaged chromosomes. Additionally, p53 triggers the production of p21, which binds to and inhibits the activity of Cdk/cyclin complexes, effectively blocking the cell cycle from continuing.