Question

What steps are necessary for Cdk to become fully active?

a) Binding to cyclin and phosphorylation
b) Disruption of cyclin binding
c) Inhibition by p53
d) Entering the G0 phase

Answer 1

Cdk becomes fully active by first binding to cyclin to form a complex and then being phosphorylated by another kinase, changing its shape and activating the complex for cell cycle progression.

Step-by-step explanation:

The steps necessary for Cyclin-dependent kinases (Cdk) to become fully active involves two key processes: binding to a cyclin protein and subsequent phosphorylation by another kinase. When Cdk binds to a cyclin, a Cdk/cyclin complex is formed, which is necessary for Cdk's activation. To reach its fully active state, this complex must then be phosphorylated at specific sites by another kinase. This phosphorylation is a crucial step as it changes the shape of the protein, thus activating the Cdk/cyclin complex, and enables it to phosphorylate other proteins that are instrumental in advancing the cell to the next phase of the cell cycle.