Flashcards in 30_DNA Damage & Cell Cycle Checkpoints Deck (17)
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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
