Brainscape's Knowledge GenomeTM

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


See full index

BS202 > 18.3 The Events of the M Phase > Flashcards

18.3 The Events of the M Phase Flashcards

1
Q

M phase involves a () of all cell components

A

major reorganization

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

4 primary stages of mitosis:

A
  1. prophase
  2. metaphase
  3. anaphase
  4. telophase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

beginning of prophase is markes by the appreance of () (each of which consists of 2 sister chromatids; daughter DNA molecules produced in S)

A

condensed chromosomes

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

sister chromatids are attached to each other at the ()

A

centromere

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

the centromere is a chromosomal region to which proteins bind to form the() → site of eventual attachment of mitotic spindle microtubules

A

kinetochore

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

cytoplasmic changes leading to the development of mitotic spindle are initiated; duplicated centrosomes move towards opposite sides of the nucleus → serve as the two poles of the () (begins to form during late prophase)

A

mitotic spindle

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

in yeasts, the nuclear envelope remains intact ()

A

closed mitosis

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

in higher eukaryotes, prophase ends when the nuclear envelope breaks down ()

A

open mitosis

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

transition period between prophase and metaphase

A

prometaphase

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

what happens in prometaphase

A

spindle microtubules (from both poles) attach to the kinetochores of condensed chromosomes

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

chromosomes shuffle back and forth until they eventually align on the metaphase plate in the center of the spindle → beginning of ()

A

metaphase

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

transition from metaphase to anaphase is triggered by the ()

A

breakage of the link between sister chromatids

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

mitosis phase where nuclei reform and chromosomes decondense

A

telophase

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

() usually begins during late anaphase and is almost complete by the end of telophase

A

cytokinesis

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

() is the master regulator of M phase transition

A

Cdk1/cycB protein kinase (MPF)

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

mitotic protein kinases: (1) and (2) families are activated coordinately with Cdk1 to signal entry into M phase

A
  1. Aurora kinase (Aurora A and B)
  2. Polo-like kinase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Cdk1, Aurora, and Polo-like kinases are activated in a positive feedback loop that works to initiate the ff. downstream pathways needed for M phase transition:

A
  1. chromatin condensation
  2. nuclear envelope breakdown
  3. fragmentation of Golgi apparatus
  4. spindle formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

nuclear envelope breakdown involves changes in all of nuclear envelope components:

A
  • fragmentation of nuclear membranes
  • dissociation of nuclear pore complexes
  • depolymerization of nuclear lamina
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

depolymerization of nuclear lamina results from the (1) by (2)

A
  1. phosphorylation of lamins
  2. Cdk1/cycB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Golgi breakdown is mediated by phosphorylation of proteins by ()

A

Cdk1 and Polo-like kinases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

centrosome maturation, separation, and spindle assembly during prophase are driven by phosphorylation of Aurora and Polo-like kinases at the ()

A

centrosomes

22
Q

during prophase, spindle formation results from the ()

A

dynamic instability of microtubules

23
Q

() allows spindle microtubules to attach to chromosomes at the kinetochores

A

breakdown of nuclear envelope

24
Q

proteins assembled at the kinetochore include () → involved in the interactions of chromosomes with microtubules

A

Aurora B kinase

25
Q

chromosomes in prometaphase shuffle back and forth due to activity of () at the kinetochore and centrosomes

A

microtubule motors

26
Q

balance of forces acting on the chromosomes leads to their alignment on the ()

A

metaphase plate

27
Q

the mitotic spindle consists of:

A
  • kinetochore microtubules: attached to the chromosomes
  • interpolar microtubules: overlap in the center of the cell
  • astral microtubules: radiate outward from centrosome towards cell periphery
28
Q

chromosome condensation is driven by (1) and (2) (members of structural maintenance of chromatin or SMC proteins), which contribute to chromosome segregation during mitosis

A
  1. condensins
  2. cohesins
29
Q

() bind to DNA in S phase and maintain linkage between sister chromatids after replication

A

cohesins

30
Q

as the cell enters M phase, () are activated by phosphorylation of both Cdk1 and Aurora B kinase

A

condensins

31
Q

once condensins are activated by (1), they replace (2) along most of the length of the chromosome → sister chromatids remain linked only at the centromere

A
  1. Cdk1 and Aurora B kinase
  2. cohesins
32
Q

condensins then induce chromatin condensation by forming () → formation of metaphase chromosomes

A

DNA loops

33
Q

the () monitors the alignment of chromosomes on the metaphase spindle

A

spindle assembly checkpoint

34
Q

progression to anaphase is mediated by activation of () → results from phosphorylation by Cdk1/cycB

A

APC/C ubiquitin ligase

35
Q

presence of () is sufficient to prevent APC/C activation

A

even 1 unaligned chromosome

36
Q

unattached kinetochores lead to the assembly of the (), which inhibits APC/C

A

mitotic checkpoint complex (MCC)

37
Q

MCC is no longer formed once () → APC/C is activated

A

all chromosomes are aligned on the spindle

38
Q

MCC consists of 4 proteins:

A
  • BubR1
  • Bub3
  • Mad2
  • Cdc20
39
Q

() is required for activation of APC/C, but it remains inactivated when bound to Mad and Bub proteins in the MCC

A

Cdc20

40
Q

Cdc20 is required for activation of APC/C, but it remains inactivated when bound to () proteins in the MCC

A

Mad and Bub

41
Q

activation of APC/C results in the ubiquitylation and degradation of 2 key target proteins that trigger metaphase to anaphase transition:

A
  1. degradation of cycB → Cdk1 inactivation → cell proceeds to exit mitosis
  2. degradation of securin (component of cohesins)→ dissociation of sister chromatids, allowing them to move to opposite poles of the mitotic spindle
42
Q

degradation of securin activates () → degrades cohesin

A

separase

43
Q

cytokinesis usually starts shortly after (1) starts; triggered by the (2)

A
  1. anaphase
  2. inactivation of Cdk1
44
Q

() remain active in anaphase and play important roles in coordinating nuclear and cytoplasmic division of the cell

A

Aurora and Polo-like kinases

45
Q

cytokinesis of yeast and animal cells is mediated by a () (forms beneath the plasma membrane)

A

contractile ring of actin and myosin II filaments

46
Q

ring formation is activated by ()

A

Aurora and Polo-like kinases

47
Q

in plant cells, cytokinesis proceeds by the formation of ()

A

new cell walls and plasma membranes

48
Q

in early telophase, vesicles carrying cell wall precursors (from Golgi) accumulate at the ()

A

former site of the metaphase plate

49
Q

vesicles fuse to form a membrane-enclosed disk; polysaccharides from the matrix of the new cell wall called a ()

A

cell plate

50
Q

summarize how cytokinesis occurs in plant cells

A
  1. in early telophase, vesicles carrying cell wall precursors (from Golgi) accumulate at the former site of the metaphase plate
  2. vesicles fuse to form a membrane-enclosed disk; polysaccharides from the matrix of the new cell wall (called a cell plate)
  3. cell plate expands outward (perpendicular to the spindle) until it reaches the PM
  4. membrane surrounding cell plate then fuses with parental PM → divides the plant cell
51
Q

() between daughter plant cells are formed as a result of incomplete vesicle fusion

A

plasmodesmata

BS202 (36 decks)

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