Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cell Bio And Disease > Mitosis Phase > Flashcards

Mitosis Phase Flashcards

1
Q

What is stopped from getting degraded in the spindle assembly checkpoint

A

Cyclin b and securin (allowing anaphase)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which m cyclin is nuclear and which moves to nucleus from cytoplasm

A

Nuclear is a

Cytoplasmic is b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When does cyclin a get degraded

A

Before prometaphase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When does cyclin b increase / peak and then lower

A

Peak is at prometaphase

Low is met- anaphase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the main cdc25 for cdk1 cyclin b activation by removal of wee1/myt1 phos

A

Cdc25b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What kinase is a target of the active cdk1 and cyclin b which causes a positive feedback loop for more activation

A

Polo like kinase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does plk do in respect to cdk 1 activation

A

Phos of wee and myt inhibiting them

Also phos of cdc25a, and c as well as b which all cause cdk activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How can cyclin a aswell as main cdc25b be a trigger for mitosis via cdk1 activation

A

When in complex with cdk it allows aurora a activation of plk

Plk then causes a loop via phos of cdc25c

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many centrioles are from centrosomes

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Explain centrosome cycle which duplicates for mitosis

A

In g1 centrosome pulls apart but held by procentrioles

Centrosome is duplicated in s phase

Centrosome disjunction through pulling of procentrioles in s/g2

Full centrosome separation in mitosis and bipolar spindle formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is pulling apart of procentrioles called in g2 and what kinase involved

A

Centrosome maturation via plk4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Other than activating cdk1 cyclin b and plk for centrosome maturation, what do plk do

A

Prophase pathway of cohesin ring removal on sister chromatid arms

Cytokinesis in the actin myosin ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is aurora a for

A

Spindle integrity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is aurora b part of

A

Cpc chromosome passenger complex

With incenp, survivin, borealin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where is aurora b and why

A

Chr arms early eg in mitosis

Moves to centromeres in prometaphase this is so it can aid correct attachment of kinetochores with mt

Via phos of kmn proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What spindle attachment is when 1 attaches to each sister

A

Amphitelic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Does amphitelic produce a sac and why

A

No sac is inactive because equal tension

18
Q

What is monotelic

A

When only 1 sister is attached

Produces active sac bc no tension so aurora b present

19
Q

What is syntelic

A

When both mt attach to one sister

Also produces active sac as no tension

20
Q

What is merotelic and why doesn’t this have active sac

A

Both arms attached but 1 has more mt attached

Tension but unequal

21
Q

Which enzyme opposes aurora B action via dephosphorylation

A

Pp1

22
Q

When does pp1 get replaced by aurora b

A

Prophase when aurora b on chr arms

23
Q

What inhibits pp1

A

i2 inhibitor

24
Q

What happens when aurora b moves from arms to centromeres in prometaphase

A

Part of sac

It checks tension. If not there aurora b will cause kinetochore assembly and phos kmn proteins causing proper attachment of k with mt

When this happens anaphase can occur

Aurora b stays in middle of cell and far from kinetochore, allowing kinetochore dissassembly and pp1 increase via i2 degradation from anaphase

25
Q

What is the strong interaction with merotelic and aurora b

A

Because stay in middle, aurora b can phos of kinetochore subunits and allow proper attachment

26
Q

What does sac block which blocks progression to anaphase

A

Apc/cdc20

27
Q

What does securin ub do and how does it allow anaphase

A

Securin degradation activates separase which cleaves cohesin rings around the centromeres = separation

28
Q

Cyclin b causes cdk inactivation and therefore dephos of its substrates , how does this allow anaphase

A

Spindle elongation and allows chr separation to poles

29
Q

How is cdk 1 inactivation good for telophase and mitotic exit

A

Nuclear formation and spindle dissassembly

30
Q

What part of sac blocks apc cdc20

A

Mitotic checkpoint complex mcc

31
Q

What are the key components of mcc

A

Mad 2 closed, bubr1, bub3

32
Q

What does mad2 closed binding to cdc20 do

A

Blocks it’s ability to recognise and degrade cyclin b and securin

33
Q

How are cyclins usually recognised by cdc20

A

N terminal destruction d box

Arg and leucine residues

34
Q

What part of apc also recognises substrates

A

Apc10

35
Q

What occurs for mcc activation

A

Mps1 phosphorylates KNL1

Allows rzz and other binding like bubr1 and bub3

Rzz recruits mad1 and 2

Mad 2 put into a closed complex which binds cdc20

Attracts others like bubr1 and bub3

36
Q

How does physical separation silence the sac

A

Aurora B once phos kmn will allow proper kinetochore attachment

When tension anaphase occurs

Aurora B moves away from kinetochores and stays in middle, allowing pp1 then to dephos and disassemble kinetochores

This silences the sac

37
Q

How does p31 comet silence sac by disrupting mcc

A

Competes with bubr1 for mad2 binding

38
Q

What phosphorylates cdc20 to cause mcc dissassembly and sac turn off

A

Cdk1

39
Q

What is the cdc20 ub dependant path

A

Cdc20 can be degraded via p31 comet ub

Allows mcc fall off and new cdc20 production without silencing

40
Q

What can dephos knl1 platform protein which blocks mcc assembly

A

Pp2a phosphatase

41
Q

How is cyclin a degraded even though sac is turned on in prometaphase nuclear degradation

A

Apc cdc20 can override the sac at this point via long D boxes of cyclin a being recognised

42
Q

What is degraded by cdh1 apc (end of mitosis)

A

Cdc20 , plk, aurora a and b

Cell Bio And Disease (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions