Question

Cyclin dependent kinases which control progression through cell cycle checkpoints are totally activated by which of the following?

(a) Binding to cyclin, plus phosphorylation by a Cdk activating protein kinase

(b) Binding to cyclins

(c) Phosphorylation by Cdk activating protein kinase

(d) Phosphorylation by a tyrosine kinase

I had been asked this question in an interview for internship.

This intriguing question comes from Regulation of the Cell Cycle by Protein Kinases in section Biosignalling of Biochemistry

Answer 1

Right choice is (a) Binding to cyclin, plus phosphorylation by a Cdk activating protein kinase

Explanation: Cyclin dependent kinases are totally activated by binding to cyclin and phosphorylation by a Cdk activating protein kinase.