19 & 20 - Cell Cycle Control 1 & 2

Question 1

Events of cell cycle

Answer 1

• G0
• G1
• S
• G2
• M

Question 2

G0

Answer 2

Terminally differentiated cells withdraw from cell cycle indefinitely

Question 3

G1 phase

Answer 3

RNA and protein synthesis. No DNA synthesis. Length depends on external conditions

Question 4

Restriction point

Answer 4

A cell that passes this point is committed to pass into S phase

Question 5

S phase

Answer 5

DNA synthesis. Doubles amount of DNA in cell. RNA and protein synthesis

Question 6

G2 phase

Answer 6

No DNA synthesis. RNA and protein synthesis continue.

Question 7

M Phase

Answer 7

Mitosis and cytokinesis yielding 2 daughter cells

Question 8

Mid g1 cyclin-CDKs

Answer 8

• Cyclin D-CDK4
• Cyclin D-CDK6

Question 9

Late g1 cyclin CDKs

Answer 9

• Cyclin E-CDK2

Question 10

S phase cyclin CDKs

Answer 10

• Cyclin A-CDK2

Question 11

Mitotic cyclin-CDKs

Answer 11

• Cyclin A-CDK1
• Cyclin B-CDK1

Question 12

G1 checkpoint

Answer 12

Is environment favourable?

Question 13

G2 checkpoint

Answer 13

Is all DNA replicated and all DNA damage repaired?

Question 14

Mitosis Checkpoint

Answer 14

Are all chromosomes properly attached to the mitotic spindle?

Question 15

Early Response genes

Answer 15

Transcription factors that turn on expression of delayed response genes

Question 16

Effect of cancer promoting mutations

Answer 16

• Increase ability of cell to proliferate
• Decrease susceptibility of cell to apoptosis
• Increase general mutation rate in cell
• Increase cells longevity

Question 17

Oncogene mutations

Answer 17

Mutation only required in one allele for tumour formation. The gene in its normal unmutated form = proto-ongogene

Question 18

Tumour suppressor gene mutations

Answer 18

For cancer to occur, both alleles of gene must be mutated and have no activity

Question 19

Retrovirus

Answer 19

Cause cancer by mutating and rearranging proto-ongogenes. Insert strong promoters near proto-oncogenes

Question 20

p53

Answer 20

Tumour suppressor protein that up-regulates expression of specific proteins. Detects damaged DNA in the G1 phase, activates the expression of p21 amd reduces the frequency of mutations in the cell.

Question 21

Rb

Answer 21

Sequesters the transcription factor E2F which is required for cell cycle progression.

Question 22

What drives apoptosis

Answer 22

the activity of cysteine-containing aspartate-specific proteases.