Question

The activation of the cdk kinase signals that a particular set of separate upstream events has been completed. Thus, cdk acts as a specific ____?

1) signal relay protein
2) signal amplifier
3) signal distributor
4) signal integrator

Answer 1

Cyclin-dependent kinases (Cdks) function as signal integrators in cell cycle regulation, becoming fully active when bound to cyclins and phosphorylated, which in turn regulates the progression through different phases of the cell cycle.

Step-by-step explanation:

Cyclin-dependent kinases (Cdks) play a critical role in the regulation of the cell cycle by acting as signal integrators. The activation of a Cdk occurs when it binds to a cyclin protein and is subsequently phosphorylated by another kinase. This process ensures that Cdks only trigger progression of the cell cycle when preceding necessary conditions are met, effectively integrating signals from different pathways and checkpoints. Cyclin-dependent kinases (Cdks) function as signal integrators in cell cycle regulation, becoming fully active when bound to cyclins and phosphorylated, which in turn regulates the progression through different phases of the cell cycle.

Cdks phosphorylate specific target proteins, leading to changes in their activity and conformation, thereby advancing the cell to the next phase of the cycle. The fluctuation of cyclin concentrations throughout the cell cycle determines when Cdk/cyclin complexes form, which are necessary for the cell cycle to proceed.