30_DNA Damage & Cell Cycle Checkpoints Flashcards Preview

BIOL 331 > 30_DNA Damage & Cell Cycle Checkpoints > Flashcards

Flashcards in 30_DNA Damage & Cell Cycle Checkpoints Deck (17)
Loading flashcards...
1

What are the cell's three reactions to DNA damage?

1) repair
2) activate checkpoint, arrest cell cycle
3) apoptosis

2

The cell cycle halts if two critical events are incomplete; what are they?

DNA replication in S phase
Chromosome alignment during M phase

3

What is the inheritance pattern of ataxia-telangiectasia?

recessive

4

What type of radiation are patients with AT sensitive to?

ionizing radiation (causing dsDNA breaks)

5

Which gene is mutated in AT patients?

ATM

6

What are ATM and ATR activated by?

ATM: dsDNA breaks
ATR: ssDNA breaks

7

What type of DNA damage does UV radiation induce?

ss-DNA breaks

8

Which type of radiation induces double-stranded DNA breaks?

ionizing radiation

9

Which checkpoint kinases do ATM and ATR activate?

ATM: Chk2
ATR: Chk1

10

Which protein is dubbed the "guardian of the genome"? At which stage does it arrest the cell cycle?

p53
G1 => S

11

Cdc25 is a (kinase/phosphatase).

phosphatase

12

What effect does phosphorylation have on cdc25?

results in its shuttling to the cytoplasm. CDK complex remains inactive, and cell cycle is arrested at G2-M.

13

Is p53 stable in its phosphorylated or dephosphorylated form?

phosphorylated

14

As a result of phosphorylation of p53, what genes are transcribed more?

p21 - CDI & Bax

15

What does p21 CDI inhibit?

G1 and S CDKs

16

What is the consequence of Bax upregulation?

apoptosis

17

Which effector is involved in arresting the cell cycle at the G2-M checkpoint?

cdc25