Cell Cycle

Question 1

cyclin and CDK of mid G1

Answer 1

cyclin D

CDK4/6

Question 2

cyclin and CDK of late G1

Answer 2

cyclin E

CDK 2

Question 3

cyclin and CDK of S

Answer 3

cyclin A

CDK 2

Question 4

cyclin and CDK of M

Answer 4

cyclin A and cyclin B

CDK 1

Question 5

What signal cascade leads to c-Fos transcription?

Answer 5

MAP kinase

Question 6

What does c-Fos transcribe?

Answer 6

mid-G1:
cyclin D
CDK4/6

Question 7

Which cyclin increases its level throughout G2 and peaks in M phase?

Answer 7

cyclin B

Question 8

Which two CDK complexes are inhibited until DNA replication have completed?

Answer 8

cyclin A/CDK1

cyclin B/CDK1

Question 9

What inhibits cyclin A/CDK 2?

Answer 9

p27KIP1

Question 10

What effect does cyclin D, CDK4/6 have on Rb?

Answer 10

phosphorylates it and releases it from E2F

Question 11

What does E2F do?

Answer 11

promotes the transcription of cyclin E/CDK2 and cyclin A/CDK2

Question 12

When is ATM activated?

Answer 12

when there are double-stranded DNA breaks, caused by irradiation

Question 13

When is ATR activated?

Answer 13

damages from UV light and certain drugs

Question 14

How do ATM and ATR work?

Answer 14

• inhibit phosphatases that normally dephosphorylate CDK complexes which then activate S-phase and mitosis
• also promotes p53 stabilization allowing it to stimulate p21CIP1, an inhibitor of CDK1/2 (no S phase or M phase)

Question 15

What disease is associated with mutation in the gene encoding ATM?

Answer 15

Ataxia Telangiectasia

Question 16

What are PUMA, BID, BAX?

Answer 16

pro-apoptotic proteins

Question 17

What is Bcl-2?

Answer 17

protein that is antiapoptotic and inhibits BAX

Question 18

What is the channel-forming protein of the mitochondrial membrae?

Answer 18

BAX, leads to release of cytochrome c from the mitochonria

Question 19

What stimulates BAX?

Answer 19

PUMA and BID

Question 20

Which is the initiator caspase and which is excecutioner caspase?

Answer 20

caspase-9 (initiator caspase)»_space; caspase-3 (executioner caspase)

Question 21

How does p53 trigger apoptosis?

Answer 21

by inducing pro-apoptotic proteins (PUMA, BID, BAX)