lecture 1

Question 1

what order is the cell cycle

Answer 1

G1, S, G2, M

Question 2

what cyclins are at what points of cell cycle

Answer 2

G1: CDK4/6 + cyclin D(1-3)
after R point: CDK2 + cyclin E
S: CDK2 + cyclin A then CDC2 + cyclin A
G2: CDC2 + cyclin B 
M: CDK2 + cyclin B

Question 3

what are the two major control factors in cell cycle control

Answer 3

normal control by cyclins

mechanisms that stop the cycle

Question 4

how do the cyclin levels fluctuate

Answer 4

Cyclin E: low in G1, rapid increase after R
Cyclin A: increase as entry to S phase
Cyclin B: increase before m phase

Question 5

what is the exception to cyclin ubiquitination as the cell cycle goes on

Answer 5

Cyclin D
expressed in G1 and is controlled by growth factors
other cyclins are controlled by IC signals

Question 6

CKI

Answer 6

cyclin inhibitor = 7 proteins that antagonise CDK/cyclin activity

Question 7

what happens at G1 checkpoint

Answer 7

is cell big enough
is environment favourable
DNA damage

Question 8

what happens at G2 checkpoint

Answer 8

is all DNA replicated
is cell big enough
is environment favourable

Question 9

what happens at metaphase checkpoint

Answer 9

are all chromosomes on spindle

Question 10

where in the cell cycle can DNA damage be detected

Answer 10

G1, entry to S phase, entry to mitosis

Question 11

how is DNA repaired in G1

Answer 11

NHEJ

Question 12

how is DNA repaired in G2

Answer 12

HR

Question 13

DNA damage response in G1

Answer 13

p53 - p21
inhibits S-CDK complexes
DNA is repaired
if DNA cant be repaired = apoptosis

Question 14

what is different in embryos

Answer 14

cyclin E and A are high in wrong phasers