Cell Cycle

Question 1

Quiescent cells

Answer 1

RBC and cells in the granulosm of the skin

Question 2

Lymphocytes divide

Answer 2

Only if activated

Question 3

Go

Answer 3

• Phase when cells are not actively dividing and cells can re-enter the cell cycle

Question 4

G 1 duration

Answer 4

11 hours

Question 5

S phase duration

Answer 5

8 hours

Question 6

G2 duration

Answer 6

4 hours

Question 7

Mitosis duration

Answer 7

1 hour

Question 8

Interphase

Answer 8

G1 phase, S phase and G2 phase

Question 9

M phase

Answer 9

mitosis and cytokinesis

Question 10

What happens in G1

Answer 10

Proliferation
Cell grows in size
RNA and protein synthesis for S phase
Growth Factor dependant

Question 11

What happens in G2

Answer 11

replication
further growth
cell organelle replication
preparation for mitosis

Question 12

What happens in S phase

Answer 12

Synthesis of DNA

Question 13

Order of mitosis

Answer 13

interphase, prophase, metaphase, anaphase and then telophase

Question 14

prophase

Answer 14

chromatin condensation
nucleolus disappears
centrioles move to poles

Question 15

pro-metaphase

Answer 15

nuclear membrane dissolves
chromosomes attach to microtubules and begin moving

Question 16

metaphase

Answer 16

spindle fibres align the chromosomes along the metaphase plate

Question 17

Anaphase

Answer 17

Paired chromosomes separate and move to opposite sides of the cell
Chromatids arrive at opposite poles of cell

Question 18

Telophase

Answer 18

New membranes form around daughter nuclei
Chromosomes decondense
Spindles disperse

Question 19

CDKs

Answer 19

regulate the cell cycle by phosphorylation

Question 20

CKIs

Answer 20

Regulate CDK activity

Question 21

Cyclins

Answer 21

activator proteins, unstable and associated with cdks

Question 22

cdk4/6 - cyclin D

Answer 22

regulate the restriction point

Question 23

cdk1 - cyclin B

Answer 23

also known as MPF and control entry to M phase. cyclin B levels rise in G2 in preparation

Question 24

activity of cdk

Answer 24

depends on presence of cyclin

Question 25

CKIs families

Answer 25

p21 CIP, p27 KIP and p16 INK

Question 26

Cyclin-dependant kinase inhibitors

Answer 26

are small proteins that block cyclin/cdk activity by forming inactive complex or competitive ligand

Question 27

MPF is needed for

Answer 27

completion of mitosis (destroys nuclear envelope, chromosome condensation and spindle formation)

Question 28

restriction point

Answer 28

-late in G1
-check for cell size and favourable environmental conditions (presence of growth factors)
-dependant on accumulation of cyclin D

Question 29

G1 checkpoint

Answer 29

DNA damage
cdk2 - cyclin E/A

Question 30

G2 checkpoint

Answer 30

DNA damage
cdk1 - cyclin A/B

Question 31

spindle assembly checkpoint

Answer 31

delays anaphase
APC is inhibited until all chromosomes are attached

Question 32

rb protein at the restriction point

Answer 32

acts as the gatekeeper at the restriction point

Question 33

E2F

Answer 33

transcribes genes for S phase when not bound to rb

Question 34

growth factor at restriction point

Answer 34

triggers the RAS pathway

Question 35

RB

Answer 35

blocks entry to the cell cycle

Question 36

p53

Answer 36

transcription factor
detects DNA damage
low levels DD result in p21 allowing DNA repair
high levels DD result in apoptosis

Question 37

BRCA1

Answer 37

DNA repair

Question 38

tumour supressor genes

Answer 38

-encode normal cell proteins that inhibit cell proliferation and growth
-maintain the integrity of the genome
-cause cell cycle arrest
-repair DNA damage

Question 39

damage to DNA

Answer 39

chemical mutagens
radiation
errors in replication