Al-Mehdi Cell Cycle

Question 1

this phase is the growth phase and lasts on ave. 11 hours

Answer 1

G1

Question 2

this phase deals w/ DNA synthesis and lasts on ave. 8 hours

Answer 2

S phase

Question 3

cell prepares to divide in this phase (prepares for mitosis); lasts on ave. 4 hours

Answer 3

G2

Question 4

how long does M phase last

Answer 4

1-2 hrs

Question 5

this phase is where cells exit or re-enter or they just stay here

Answer 5

G0

Question 6

neurons, skeletal and cardiac m, RBC’s stay in this phase

Answer 6

G0

Question 7

hepatocytes, lymphocytes, PCT, periosteal cells are stable in G0, but can reenter into what phase

Answer 7

G1

Question 8

what causes side effects of cancer drugs

Answer 8

the drugs target rapidly dividing cancer cells and normal cells and travel in hte blood so it effects whole body, especially the organs that have rapidly dividing cells

Question 9

bone marrow, gut epithelium, skin, and hair follicles, and germ cells are never in this phase b/c rapidly dividing

Answer 9

G0

Question 10

checkpoint for DNA damage

Answer 10

G1/S

Question 11

checkpoint for unduplicated DNA

Answer 11

G2/M

Question 12

checkpoint for proper attachment of chromosomes to mitotic spindle

Answer 12

Mitotic Spindle checkpoint

Question 13

policeman of G1/S checkpoint

Answer 13

Rb (retinoblastoma protein)

Question 14

CDKs do what to Rb for cell cycle to proceed

Answer 14

phosphorylate

Question 15

what has to bind to Rb for progression to S phase

Answer 15

Cyclin D and CDK4/6

Question 16

S phase cyclins and CDKs

Answer 16

Cyclin E and CDK2
Cyclin A and CDK2

Question 17

G2 phase cyclins and CDKs

Answer 17

Cyclin A and CDK2
Cyclin B and CDK1

Question 18

MS phase cyclin and CDK

Answer 18

Cyclin B and CDK1

Question 19

CDK inhibitors (CDKIs) of CDK 4/6

Answer 19

p15, p16

Question 20

CDK inhibitors (CDKIs) of multiple CDKs

Answer 20

p21

Question 21

this protein is guardian of genome and senses a problem and stops cell cycle

Answer 21

p53

Question 22

what protein activates CDKIs if there is a problem in cell cycle; arrests cell in G1

Answer 22

p53

Question 23

DNA damage checkpoint:

Answer 23

1. phosphorylate p53 and mdm2 by ATM
2. p53 separates from mdm2
3. cell cycle arrest (CDKIs)

Question 24

special agents that sense if damage is beyond repair and control BCL-2 expression

Answer 24

BAD/BID/BIM

Question 25

protein that is anti-apoptotic

Answer 25

BCL-2

Question 26

cell damage beyond repair steps:

Answer 26

1. sensed by BAD/BID/BIM
2. they suppress BCL-2
3. BAX/BAK activation (OMM channel)
4. apoptosis (cyt c released, recruits APAF-1, then procaspase 9 to caspase 9 to apoptosis

Question 27

what protein wants to increase cell division and proliferation, but ends up actually stopping cell cycle progression itself

Answer 27

oncogene (myc)

Question 28

Oncogene checkpoint:

Answer 28

1. myc (oncogene) makes p14ARF
2. p14ARF has high affinity for mdm2
3. mdm2 separates from p53
4. p53 phosphorylated and activated and makes CDKIs
5. cell cycle arrest

Question 29

this toxin by itself can cause mutation in p53

ex. if person has mutation of p53, and another mutation arises, person will get liver cancer (two-hit hypothesis)

Answer 29

Aflatoxin