Question

Different cyclin-cdk complexes trigger different steps in the cell cycle. The cyclin that acts in G2 to trigger entry into M phase is called _____, and the active complex it forms with its Cdk is called _____. Other cyclins, called _____ and _____ bind to a distinct Cdk protein late in G1 to form S-Cdk and G1/S-Cdk; these cyclin-cdi complexes help launch the S phase. Another group of cyclins, called _____, act earlierin G1 and bind to other Cdk proteins to form _____, which help drive the cell through G1 toward S phase.

Answer 1

The specific cyclins and Cdk that regulate the cell cycle at various checkpoints are cyclin B and M-Cdk for G2/M transition, cyclin E and A for S-Cdk and G1/S-Cdk to initiate S phase, and cyclin D for G1-Cdk to drive the cell from G1 to S phase.

Step-by-step explanation:

Cyclin-cdk complexes play critical roles in the progression of different stages of the cell cycle. The cyclin that acts in G2 to trigger entry into M phase is called cyclin B, and the active complex it forms with its Cdk is called M-Cdk. Other cyclins, called cyclin E and cyclin A bind to a distinct Cdk protein late in G1 to form S-Cdk and G1/S-Cdk; these cyclin-Cdk complexes help launch the S phase. Another group of cyclins, called cyclin D, act earlier in G1 and binds to other Cdk proteins to form G1-Cdk, which helps drive the cell through G1 toward S phase.