Cell Division

Question 1

what is the cell cycle critically controlled by?

Answer 1

cdk - cyclin-dependent kinases

Question 2

when is cdk activity at its peak?

Answer 2

during mitosis

Question 3

what is cdk regulated by?

Answer 3

+ phosphorylation

+ dephosphorylation

Question 4

which cdk complex controls events in S phase of cell division?

Answer 4

active S-cdk

Question 5

which cdk complex controls events in M phase of cell division?

Answer 5

cdk1 = cdc2

Question 6

which cdk complex controls events during G1 phase of cell division?

Answer 6

cdk4/6

Question 7

which cdk complex controls events between R point of G1 and start of S phase of cell division?

Answer 7

cdk2

Question 8

which cdk complex controls events from start to middle of S phase of cell division?

Answer 8

cdk2

Question 9

which cdk complex controls events from mid S phase M to end of G2 phase of cell division?

Answer 9

cdk1 = cdc2

Question 10

how many checkpoints are there in G1?

Answer 10

1. damaged DNA

2. unfavourable extracellular environment

Question 11

how many checkpoints are there in S phase?

Answer 11

1. damaged or incompletely replicated DNA

Question 12

how many checkpoints are there in G2?

Answer 12

1. damaged or incompletely replicated DNA

Question 13

how many checkpoints are there in M phase

Answer 13

1. chromosome improperly attached to mitotic spindle

Question 14

when is the checkpoint for growth or quiescence?

Answer 14

R-Point (G1/S transition)

Question 15

what disease can defects in cohesion cause?

Answer 15

Roberts Syndrome

- very rare

Question 16

how are sister chromatids held together?

Answer 16

cohesion complex/rings made of cohesin

Question 17

what do defects at spindle checkpoint cause?

Answer 17

aneuploidy

Question 18

which cyclin controls events in M phase of cell division?

Answer 18

cyclin B

Question 19

which cyclin controls events during G1 phase of cell division?

Answer 19

cyclin D

Question 20

which cyclin controls events between R point of G1 and start of S phase of cell division?

Answer 20

cyclin E

Question 21

which cyclin controls events from start to middle of S phase of cell division?

Answer 21

cyclin A

Question 22

which cyclin controls events from mid S phase to end of G2 phase of cell division?

Answer 22

cyclin A

Question 23

what is the role of p53 in DNA damage?

Answer 23

directs transcription of cdk-inhibitors

Question 24

what is CHK2 activated by?

Answer 24

DNA damage

Question 25

what is the role of CHK2?

Answer 25

inhibits cdc25

Question 26

what are the stages of mitosis?

Answer 26

• prophase
• prometaphase
• metaphase
• anaphase
• telophase
• cytokinesis

Question 27

In metaphase, what must first happen for mitosis to proceed?

Answer 27

chromosomes are properly attached and under tension

Question 28

what checkpoint occurs during metaphase?

Answer 28

spindle checkpoint

Question 29

what occurs during prophase?

Answer 29

chromosomes become visible as paired chromatids and the nuclear envelope disappears

Question 30

what happens during prometaphase?

Answer 30

phosphorylation of nuclear pore proteins and lamins by M-CDK causes the nuclear membrane to break down into numerous small vesicles. As a result, the spindle microtubules now have direct access to the genetic material of the cell