Part 7: Cell cycle

Question 1

Function of cyclin dependent kinase

Answer 1

• Phosphorylates Ser and Thr on target protein

- Exists for specific cell cycle (e.g. activates TFs)

Question 2

Cyclin protein

Answer 2

• Complexes CDK and activates it

- Created and degraded during certain cell phases

Question 3

What’s the direct effect of a loss-of-function mutation in the gene encoding G1 specific cyclin on the cell cycle?

a) Failure to enter G1 phase
b) Failure to enter S phase
c) Failure to enter G2 phase
d) Failure to enter M phase

Answer 3

Can not enter S phase

Question 4

What are two major check points of the cell cycle?

Answer 4

Between G1 and S, between G2 and M. Cell can be arrested if not ready for replication (insufficient growth), has damaged DNA or there are enough cells in the tissue

Question 5

How is CDK-cyclin complex controlled?

Answer 5

• Phosphorylation/dephosphorylation

- Interactions with positive and negative regulatory proteins

Question 6

What’s the effect of a loss-of-function mutation in a negative regulator of apoptosis?

a) Increased cell number
b) Decreased cell number

Answer 6

Increased cell death

Question 7

What’s the effect of a gain-of-function mutation in a negative regulator of cell division?

a) Increased cell number
b) Decreased cell number

Answer 7

Decreased cell number