9.9 Cell Cycle Flashcards

1
Q

what does the cell do in G1 phase?

A

it gathers nutrients and energy. Lives and prepares

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2
Q

what does the cell do in the S phase?

A

it commits to duplication and division. DNA/organelle replication

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3
Q

what does the cell do in the G2 phase?

A

it checks and fixes DNA

DNA repair

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4
Q

what does the cell do in M phase?

A

divide

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5
Q

what are the three locations of the major cell cycle checkpoints?

A

G1/S transition
G2/M transition
metaphase/anaphase transition

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6
Q

what causes transition between G1 to S phase?

A

increase in CycE-Cdk2 levels

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7
Q

CycE-Cdk2 increase levels of what other cyclin?

A

CycA

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8
Q

CycA degrades _____ (what cyclin)

A

CycE

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9
Q

what does CycA do?

A

it induces DNA replication in S phase

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10
Q

CycB (inactivated) increases and is maximal before ____ phase. It degrades Cyc___.

A

M phase

CycA

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11
Q

CyB is regulated by phosphorylation by two enzymes: ______ and ______. Which inhibits and which activates?

A

CAK - activated

Wee - inhibits

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12
Q

to activate CycB, the inhibitory phosphate needs to be removed by _______.

A

Cdc25

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13
Q

what activated Cdc25 to dephosporylate the inhibitory phosphate on CycB?

A

complete and accurate DNA replication

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14
Q

once the inactivating inhibitory phosphate is removed from CycB, what phase transition can happen?

A

G2 –> M phase

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15
Q

what is the “anaphase wait” signal?

A

all kinetochores are attached with a microtubule and ready to split

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16
Q

Wee1 inhibits what?

A

CycB-Cdk1

17
Q

once anaphase is reached, what is expressed? What do they do?

A

APCs are expressed, they degrade CycB and CycA

18
Q

what regulates CDKs? (4)

A
  1. cyclin changes (either increase in expression through TFs or degradation such as APCs)
  2. Phosphorylation (Wee, CAK)
  3. CKIs (CDK inhibitors) in G1
19
Q

what are CKIs? (p21, p27, etc)

A

inhibitors of CDK

20
Q

what is pRB? Is it an oncogene or a tumor suppressor gene?

A

it is a protein that connects to E2F (on oncogene) and suppresses its activity.

21
Q

pRB suppresses ______, which is an oncogene.

A

E2F

22
Q

E2F goes to the nucleus and acts as a TF, expressing ________, inducing which transition?

A

CycE

G1/S transition

23
Q

what oncogene acts as a TF that induces CycE expression, inducing transition from G1 to S phase? what suppresses this?

A

E2F

pRB

24
Q

an oncogenes normal activity is to ______ the cell cycle.

A

progress

25
Q

a tumor suppressor gene functions to ______ the cell cycle

A

slow

26
Q

RB, p53, p16 (CKIs) are examples of:

A

tumor supressor genes

27
Q

myc, ras, raf, cdc25, Cdks, cyclins, EGFR are examples of:

A

oncogenes

28
Q

_____/_____ detect DNA damage

A

ATM/ATRs

29
Q

ATM/ATRs can activate _____ (a CKI) which assures cells have time to repair damage or if the damage is too extensive, initiate apoptosis

A

p53

30
Q

p21 inhibits ____s

A

CDKs

31
Q

reverse in inhibition of ______ allows the cell to progress to M phase from G2 phase

A

CycB

32
Q

in response to mitogen, cyc____-Cdk phosphorylates E2F, causing it to express cyclin E and A

A

D