Brainscape's Knowledge GenomeTM

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


See full index

Histology Exam I > Cell Cycle > Flashcards

Cell Cycle Flashcards

1
Q

Prophase

A

condensation of chromosomes; breakdown
of nuclear membrane; formation of mitotic spindle;
attachment of spindle fibers to kinetochores of
chromosomes

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

Metaphase

A

lining up of chromosomes on metaphase

plate

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

Anaphase

A

separation of sister chromatids of each
chromosome & their movement to spindle poles;
beginning of cytokinesis.

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

Telophase

A

reformation of the nuclei (& nuclear
membrane); decondensation of chromosomes;
completion of cytokinesis

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

Are 1st and 2nd meiotic division reductional or equatorial?

A

1st is reductional and 2nd is equatorial

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

When do crossover events occur?

A

prophase I

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

Number of chromosomes and amount of DNA at the end of 1st division

A

chromo: 1n and DNA is 2d

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

Number of chromosomes and amount of DNA at the end of 2st division

A

chromo: 1n and DNA 1d

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

how many phases of the cell cycle can be seen in LM?

A

2: interphase and division

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

how many phases does cell cycle have?

A

4: G1, S, G2, M

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

What happens in G1 phase?

A

period of normal cell growth and metabolism

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

What happens in S phase?

A

DNA synthesis

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

What happens in G2 phase?

A

synthesis of proteins and factors necessary for cell division

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

What happens in M phase?

A

cell division and cytokinesis

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

Describe G0 phase

A

adult cells that divide occasionally, undergo limited growth and active metabolism, to divide need to be stimulated by factors such as growth factors

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

Describe Gtd phase?

A

terminally differentiated cells

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

Cells in Gtd phase?

A

cardiac muscle cells and neurons

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

Cells in G0 phase?

A

kidney cells, liver cells, and lung cells

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

How do cells escape G0 phase?

A

stimulant such as Growth Factor

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

Where is the passage of G0 phase to divisional cycle controlled at? Germ cells?

A

restriction point at G1 phase and for germ cells there is a 2nd restriction point in G2 which require proper hormonal stimulation to enter meiosis

21
Q

Define restriction points

A

control points in cycle under the influence of extracellular signals

22
Q

Define check points

A

control point in cycle that monitor DNA damage, proper DNA replication, proper alignment of chromosomes, etc. to ensure proper replication of undamaged genes to daughter cels

23
Q

What two fammilies of molecules control restriction and check points?

A

Cdks and cyclins

24
Q

What are the Cdk-cyclin complexes for G1-S?

A

Cyclin D- Cdk4/6 and Cyclin E-Cdk2`

25
Q

What is the Cdk-cyclin complex for S?

A

Cyclin A-Cdk2

26
Q

What is the Cdk-cyclin comples for S-G2?

A

Cyclin A-Cdk1

27
Q

What is the Cdk-cyclin complex for M?

A

Cyclin E-Cdk1

28
Q

Describe the 4 major ways in which the specificity of a Cdk is regulated?

A
  • particular cyclin bound to it
  • activation by phosphorylation at Threonine near position 160
  • inactivation by phosphorylation at Threonine 14 and Tyrosine 15
  • interactions with Cdk inhibitor CKI
29
Q

Describe the process of Cyclin D exerting its effects

A

Cyclin D is synthesized in response to growth factors and binds Cdk4 and Cdk 6. Cyclin D/Cdk4 phosphorylate pRb t up to 16 sites allowing release of E2F. E2F turns on the transcription of genes for S phase.

30
Q

What molecule is necessary to bypass G1 restriction point?

A

Cyclin D

31
Q

Where does pRb bind E2F?

A

E2F is a TF and pRb binds it at promotes gene regions

32
Q

Is pRb phosphorylated when binding E2F?

A

No, phosphorylation causes release

33
Q

What CKI blocks progression through G1 restriction point? How?

A

p16, by bining to Cyclin D/Cdk4 complex

34
Q

Describe effects of Adenovirus E1A in Rb-E2F complex?

A

competes with E2F for binding to Rb thus blocking its normal binding to Rb.

35
Q

Describe effects of human papillomavirus in Rb-E2F complex?

A

encoded E7 induces degradation of Rb through the ubiquitin-proteasome pathway.

36
Q

Describe effects of SV40 T Antigen in Rb-E2F complex?

A

directly disrupts Rb-E2F complexes.

37
Q

When is p53 activated and what is its immediate effect?

A

activated by DNA damage and causes transcription of p21

38
Q

What are the overall effects of p53? What happens if DNA cannot be repaired?

A

blocks progression of cell cycle and cell division until DNA is repaired, if it cant then accumulated p53 will initiate apoptosis

39
Q

What is the function of p21?

A

it is ta general inhibitor of a number of Cdk.cyclin complexes and also blocks a cofactor of DNA pol (PCNA)`

40
Q

What determines wether apoptosis occurs?

A

it is a balance between pro-apoptotic and anti-apoptotic factors

41
Q

Which family of proteins are among the most potent apoptosis regulators?

A

Bcl-2 family (anti and pro apoptotic)

42
Q

What molecule binds p53 to inactivate it?

A

mdm2

43
Q

What are the microscopic events normally observed un apoptosis?

A

DNA fragmentation, chromatin condensation, fragmentation of nucleus, and fragmentation of the cell

44
Q

Describe the difference between necrosis and apoptosis

A

necrosis: cellular contents and degradative enzymes often spill out into surrounding tissue causing inflammation… apoptosis: remain intact and are destroyed cleanly by macrophages

45
Q

Describe the common conserved pathway of apoptosis:

A
  • Proteins that promote apoptosis are induced
  • Endonucleases fragment and destroy nucleus
  • Cyto C and other apoptosis inducing factors from mitochondria are released
  • Cyto C activates caspase proteases in cytoplasm
  • Proteases destroy the cell
46
Q

What molecule is among the most potent of apoptosis inducing factors?

A

Cyto C

47
Q

Caspase proteases are members of what protein family?

A

ICE family of cystein proteases

48
Q

How does radiation therapy for cancer work?

A

Radiation therapy and many of drugs for cancer therapy involve induction of damage in DNA of cancer cell. P53 blocks the cell cycle until the DNA is repaired, and if it cannot be repaired induces death of the cell by apoptosis.

49
Q

Why are some cancer cells resistant to radiation therapy?

A

because they have loos or mutation in p53

Histology Exam I (6 decks)

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