Cell Division And The Cell Cycle

Question 1

Growth factors

Answer 1

Extracellular signal to stimulate cell growth and proliferation

Question 2

How are normal cell populations maintained?

Answer 2

Through proliferation, differentiation, stem cell regeneration, apoptosis

Question 3

The four phases of the cell cycle

Answer 3

G1, S, G2, M

Question 4

G1-to-S phase cyclin-CDKs

Answer 4

Cyclin D - CDK4
Cyclin D - CDK6
Cyclin E - CDK2

Question 5

S phase cyclin-CDKs

Answer 5

Cyclin A - CDK2

Cyclin A - CDK1

Question 6

G2-to-M phase cyclin-CDK

Answer 6

Cyclin B - CDK1

Question 7

CDK inhibitors

Answer 7

The p21 family and the p16 family

Question 8

p21 family of CKIs

Answer 8

Inhibit all CDKs

p21, p27, p57

Question 9

p16 family of CKIs

Answer 9

Inhibits cyclin D - CDK4/6 specifically

p15, p16, p18, p19

Question 10

How cell cycle is regulated

Answer 10

Cyclin binding, phosphorylation of CDK, CKI binding, and inhibition or activation of CKIs

Question 11

Major cell cycle checkpoints

Answer 11

Restriction point (G1)
Check for DNA damage (G1/S checkpoint)
Check for DNA damage or stalled DNA replication (S)
Check for damaged or unduplicated DNA (G2/M checkpoint)
Check for chromosome attachment to mitotic spindle (M)

Question 12

Restriction point

Answer 12

Controlled by RB, when activated is bound to E2F and no transcription occurs. When RB is not bound to E2F, E2F can transcribe cyclin A for use in the S phase

Question 13

ATM/ATR

Answer 13

Kinases that trigger the checkpoints to stop cell growth in response to DNA damage

Question 14

Chk1/2

Answer 14

Checkpoint kinases that activate p53 to stop cell growth and inactivate Cdc25 from continuing the cell cycle when DNA is damaged

Question 15

Cdc25

Answer 15

CDK activating phosphate that is active when there is no damage to DNA

Question 16

p53

Answer 16

A tumor suppressor that creates p21 to halt the cell cycle in the case of DNA damage

Question 17

p21

Answer 17

CDK inhibitor, stops the continuation of the cell cycle by inhibiting cyclin-CDK complexes

Question 18

Mitogen/growth factor

Answer 18

Activates Ras to begin the cell cycle

Question 19

Ras

Answer 19

Activates myc to continue cell cycle

Question 20

myc

Answer 20

Activates cyclin D - CDK4 to start the cell cycle

Question 21

p16

Answer 21

In differentiated cells, acts to inhibit cyclin D - CDK4 and halt the cell cycle

Question 22

Cyclin D - CDK4

Answer 22

When activated, inhibits the binding of Rb to E2F

Question 23

Rb

Answer 23

Binds E2F to inactivate transcription

Question 24

E2F

Answer 24

Transcription factor that transcribes S phase genes

Question 25

Cyclin E - CDK2 and cyclin A - CDK2

Answer 25

Trigger cell to replicate DNA

Question 26

Cyclin A - CDK1 and cyclin B - CDK1

Answer 26

Trigger cell to enter mitosis

Question 27

What happens with chromosomes are not aligned?

Answer 27

Mad2 inhibits APC/C