Brainscape's Knowledge GenomeTM

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


See full index

Cell Biology > Cell Cycle > Flashcards

Cell Cycle Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What two stages of the cell cycle are encompassed by the M phase?

A

Mitosis and cytokinesis

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

What is the collective name for the G1, S and G2 phases?

A

Interphase

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

Which phase of the cell cycle is the longest and which the shortest?

A

Longest - G1

Shortest - M

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

How can cells in the G0 phase re-enter the cycle?

A

These cells can reenter the cycle open stimulation by mitogens

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

What is the name of the G1 checkpoint?

A

Restriction Point

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

Cdk concentration fluctuates throughout the cell cycle whereas cyclin concentration is constant. T/F?

A

False - the opposite is true

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

What are the two functions of S-Cdk complexes?

A

To phosphorylate proteins to initiate helix unwinding, thus preparing for DNA replication
To prevent re-initiation of DNA replication at the same origin during the same cycle

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

How are cyclin-Cdk complexes deactivated?

A

Specific enzyme complexes add ubiquitin chains to cyclins that label them for destruction in the proteasome.

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

Why is it important that cells grow in between cell divisions?

A

Cells must at least double in size so that the daughter cells are not smaller than the mother cell upon division of the cytoplasm.

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

What is checked at the M checkpoint?

A

That chromosomes are correctly aligned on the metaphase plate and attached to spindles

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

What is checked at the G1 checkpoint?

A

The G1 checkpoint ensures that growth conditions are favourable and that DNA is undamaged

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

What is checked at the G2/M checkpoint?

A

This checkpoint ensures that DNA is replicated and undamagaed

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

Where on the chromosome is DNA replication initiated?

A

The origin of replication.

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

After DNA replication the two sister chromatids are tightly bound together by…?

A

Cohesion rings

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

What type of cells remain in the G0 phase for the entirety of their mature lifetime?

A

Neurons

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

At what point does the cell no longer require the presence of growth factors?

A

Following the G1 checkpoint

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

How does DNA damage prevent the cell from entering S phase?

A

DNA damage causes an increase in p53 concentration. p53 is a transcription regulator which activates the transcription of p21 which inhits G1/S-Cdk and S-Cdk. These cyclin- pCdk complexes guard the restriction point and their inhibition prevents the cell from passing into S phase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Following DNA damage, if DNA cannot be repaired what process will be initiated by p53?

A

Apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

During apoptosis changes are made in terms of glycosylation and receptor expression of the cell. Why is this important?

A

This facilitates recognition and engulfment by macrophages.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the two components of Maturation promoting factor?

A

Cyclin B and Cdk 1

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

What are the three functions of Maturation promoting factor?

A

Initiate chromosome condensation
Promote breakdown of nuclear membrane
Initiate assembly of mitotic spindle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The phosphorylation of which set of proteins leads to the condensing of chromosomes?

A

Condensins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the mitotic spindle composed of?

A

Microtubules and their associated motor proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the contractile ring composed of and where is it situated?

A

It is composed of actin and myosin filament which form a ring around the cell that assembles just beneath the plasma membrane.

25
Q

What occurs during prophase?

A

The replicated chromosomes condense and the mitotic spindle begins to form outside the nucleus.

26
Q

What happens in prometaphase?

A

The nuclear membrane breaks down and spindle microtubules attach to the chromosomes.

27
Q

What happens in metaphase?

A

The mitotic spindle gathers the chromosomes so that they line up on the equator of the cell

28
Q

What happens during anaphase?

A

The two sister chromatids are synchronously pulled apart and the spindle draws them to opposite poles of the cell.

29
Q

What happens during telophase?

A

The nuclear reassembles around each of the two sets of chromosomes to form two new nuclei.

30
Q

What is cytokinesis and when does it take place?

A

Cytokinesis is the splitting of the cytoplasm into two new daughter cells that begins in anaphase and continues through to telophase

31
Q

When does centrosome duplication begin and what triggers this?

A

Duplication begins at the start of S phase and is triggered by the same cyclin-kinase complexes that trigger DNA replication (G1/S-Cdk and S-Cdk)

32
Q

What is meant by the description of the mitotic spindle as ‘dynamically instable’?

A

The microtubules can depolymerize and polymerize rapidly so as to grow and shrink

33
Q

How is the basis of the mitotic spindle formed?

A

Some of the microtubules from opposite poles will join together to increase their stability, this forms the basis of the mitotic spindle.

34
Q

What triggers the dissolving of the nuclear membrane in mitosis?

A

Phosphorylation and consequent disassembly of nuclear pore proteins and intermediate filament proteins of the lamina. The phosphorylation of the lamins is done by kinase C and cyclin A activated Cdk 1.

35
Q

To which protein complex do spindle microtubules attach?

A

The kinetochore

36
Q

When and where does the kinetochore assemble and what is its assembly dependent on?

A

The kinetochore assembles on the centromere of replicated chromosomes during late prophase and their assembly is dependent on the centromere DNA sequence.

37
Q

How is separase kept inactive until the start of anaphase?

A

By binding to the inhibitory protein securin

38
Q

What targets securin for destruction at the start of anaphase?

A

Anaphase-Promoting Complex (APC)

39
Q

APC can target M cyclin for destruction. What effect does this have?

A

M cyclin destruction inactives the M-Cdk complex and drives the cell out of mitosis

40
Q

What happens in Anaphase A?

A

Kinetochore microtubules shorten by depolymerisation.

41
Q

What happens in anaphase B?

A

Spindle poles move themselves further apart.

42
Q

How is the nuclear membrane reformed?

A

By the dephosphorylation of nuclear pore proteins and nuclear lamins.

43
Q

What structure, positioned perpendicular to the long axis if the mitotic spindle, ensures each daughter cell receives one copy of the full chromosome set?

A

Cleavage furrow

44
Q

The Bcl2 family of proteins are important in mitosis. Give examples of these proteins which inhibit apoptosis and examples of those which promote apoptosis.

A

Inhibit - Bcl-2 and Bcl-X1

Promote - Bax and Bak

45
Q

Why must cells duplicate in size before they divide?

A

To ensure that the daughter cells are not smaller than the parent cells

46
Q

With which cyclin do Cdk 4 and Cdk 6 bind to at the start of G1?

A

Cyclin D

47
Q

With which cyclin does Cdk 2 bind to at the end of G1 phase?

A

Cyclin E

48
Q

With which cyclin does Cdk 2 bind with in S phase?

A

Cyclin A

49
Q

With which cyclin does Cdk1 bind to at the end of G2?

A

Cyclin A

50
Q

CDk 1 combines with which cyclin in M phase?

A

Cyclin B

51
Q

Following which point in the cell cycle does the cell no longer require growth signals and is unresponsive to antimitogenic signals?

A

Restriction point

52
Q

How does an increase in the activity and concentration of p53 in response to DNA damage lead to cell cycle arrest?

A

P53 is a transcription regulator that activates the transcription of p21. P21 is an inhibitor protein which binds to the cyclin-CDK complexes present in G1 to prevent the cell from going into S phase.

53
Q

Why would a cell be stopped from entering M phase?

A

Because there is NA damage or because DNA is not completely replicated

54
Q

Describe how the protein myc functions to cause apoptosis.

A

It is a transcription factor which activates the expression of many genes involved in cell proliferation but can down regulate Bcl2 to cause apoptosis

55
Q

Cyclin dependent kinase inhibitors are small molecules which block cyclin/CDK activity either by forming an inactive complex or by acting as a competitive CDK ligand. Give examples of these inhibitors?

A

p21 CIP
p27 KIP
p16 INK

56
Q

Which cyclin/CDK complex is known as maturation promoting factor?

A

Cyclin B and CDK1

57
Q

What is the action of maturation promoting factor which allows progression to M phase?

A

Nuclear enveloped destroyed by phosphorylation of lamins
Chromosome condensation
Spindle formatiom

58
Q

What is a cell cycle checkpoint?

A

A point in the eukaryotic cell division cycle where progress through the cycle can be halted until conditions are suitable for the cell to proceed

59
Q

Cell monitoring occurs at checkpoints in the cell cycle. What can be monitored?

A 
Favourable external and internal environment
DNA damage
Replication errors
Spindle formation
Chromosome integrity

Cell Biology (6 decks)

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