Cell cycle and division.

Question 1

4 phases of the cell cycle?

Answer 1

G1 - before DNA synthesis
S - DNA synthesised, chromosomes duplicated
G2 - synthesis complete
mitosis

Question 2

checkpoints in the cell cycle?

Answer 2

End of G1
End of G2
during metaphase

Question 3

what mediates cell cycle progression?

Answer 3

Cyclins and CDK
phosphorylation of proteins

Question 4

what are cyclins?

Answer 4

proteins that bind to CDKs to activate them

Question 5

What are CDKs?

Answer 5

enzymes that phosphorylate proteins

Question 6

What are liable cells?

Answer 6

constantly dividing cells
regenerate rapidly

Question 7

what are stable cells?

Answer 7

low level replicating
rapidly divide in response to stimuli

Question 8

what are non-dividing (permanent cells)?

Answer 8

fully differentiated
unable to proliferate/divide

Question 9

what does cyclin D bind to?

Answer 9

CDK 4 & 6

Question 10

what does p15/16 do?

Answer 10

tumour suppressor protein
bind to CDK 4/6 and inhibits cyclin D activity

Question 11

what is Rb attached to?

Answer 11

E2F transcription factor

Question 12

what phosphorylates Rb?

Answer 12

cyclin D CDK4/6 complex
cyclin E CDK 2 complex

Question 13

what inhibits cyclin e?

Answer 13

p21/27

Question 14

what happens when Rb is phosphorylated?

Answer 14

release of E2F
cell cycle progression