3-cell cycle

Question 1

4 main extracellular signals that regulate cell survival, growth and division

Answer 1

1. survival factors
2. growth factors
3. mitogens
4. growth inhibitory signals

Question 2

survival factors suppress

Answer 2

apoptosis

Question 3

GFs stimulate

Answer 3

an increase in the size of a cell

Question 4

mitogens stimulate

Answer 4

cell division

Question 5

growth inhibitory signals promote

Answer 5

differentiation and inhibit cell growth and division

Question 6

upon entering G1, daughter cells can

Answer 6

leave the cell cycle or continue in proliferative state

Question 7

what happens during S

Answer 7

entire genome is replicated

Question 8

the decision whether to divide or go in G0 occurs during

Answer 8

G1 phase

Question 9

during the question period in G1, cells respond to

Answer 9

mitogenic signals and growth inhibitory signals

Question 10

After R, they no longer respond to

Answer 10

external signals

Question 11

once a cell passes through R, it is committed to

Answer 11

going through the entire cell cycle

Question 12

central components of the cell cycle control system are

Answer 12

CDKS

Question 13

at each stage of the cycle

Answer 13

a specific CDK- cyclin phosphorylates the proteins to execute the next step

Question 14

CDKS are _____ present

Answer 14

always

Question 15

cyclin levels _____

Answer 15

fluctuate

Question 16

cyclin D is important because it is synthesized in response to

Answer 16

external growth promoting signals

Question 17

cyclin D- CDK 4/6 complex phosphorylates substrates that allow the cell to pass through

Answer 17

G1 and pass R

Question 18

The cyclin D-CDK 4/6 complex promotes progression through the restriction point by

Answer 18

phosphorylating Rb

Question 19

without mitogenic signals, Rb forms a complex with

Answer 19

E2F transcription factors

Question 20

when bound to Rb, E2F TFs are unable to stimulate

Answer 20

gene transcription

Question 21

hypophosphorylation of Rb causes

Answer 21

Rb to let go of E2F which can now stimulate gene transcription