Cell Cycle

Question 1

Classes of Cyclin-cdk complexes

Answer 1

G1-cdk-Cyclin D
G1/S-cdk-Cyclin E
S-cdk-Cyclin A
M-cdk-Cyclin B

Question 2

CAKs

Answer 2

Phosphorylates the activating site on the cyclin-cdk complex

Question 3

Wee1

Answer 3

Phosphorylates the inhibitory site on the cyclin-cdk complex

Question 4

cdc25

Answer 4

Removes the phosphate from the inhibitory site on the cyclin-cdk

Question 5

APC

Answer 5

Regulates M-cyclin by pushing it into being degraded by the proteasome so to allow the cell to progress into cytokinesis

Question 6

SCF

Answer 6

Regulates CKI by pushing it into being degraded by the proteasome so to allow the cell cycle to continue

Question 7

CKIs

Answer 7

CKIs are cdk inhibitors, it binds directly to the cyclin-cdk complex making it inactive (long term). CKIs are from the p21 family of genes.

Question 8

Explain why the loss of p53 activity can increase the proclivity for cancer

Answer 8

If there is DNA damage and there is the loss of p53, p21 would not be translated therefore the cell cycle would not arrest and would continue to grow and lead to abnormal proliferation.