Brainscape's Knowledge GenomeTM

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


See full index

Pom > Cell Replication > Flashcards

Cell Replication Flashcards

1
Q

What is the cell cycle

A

Duplication
Division
Coordination

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

Which phases make interphase

A

G1

S (DNA replication)

G2

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

What is the M phase

A

Mitosis and cytokineses

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

What is the quiescent phase

A

Inactive stage that occurs when cell leaves the cell cycle in absence of stimulus
Cell is non dividing not dormant
G0 is thus phase
Eg neurons skeletal muscles hepatocytes

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

Why might a cell pause during cell cycle

A

DNA repair
Undergo apoptosis if mistakes in DNA replication are too much to repair

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

How might cells leave G0

A

Response to extracellular factors eg growth factors
Signal amplification
Signal integration by other pathways
MAP kinases eg ras/raf/MEM/ERK

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

G1

A

Cell growth
Contains checkpoint which checks for damaged dna

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

G2

A

Preparation for mitosis
Checks for damaged or incompletely replicated DNA

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

Ras/RAF/MEK/REK

A

Increase protein synthesis
Inhibit protein degradation
Allows net growth of cell

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

C-Myc

A

Regulates cell cycle entry
Is an oncogene which is overexpressed in many tumors
C-Myc-transcription factor stimulates expression of cell cycle genes
Promotes G0 to G1

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

What oncogene causes progression of cell from G0 to G1 phase and how does it do this?

A

C-Myc
Increases concentration if cyclin D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
  • What is the purpose of Cyclin dependent kinase (Cdk)?
A

Phosphorylation and dephosphorylation of serine/threonine/tyrosine
Part of signallung events

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

Where are cdks found

A

In all proliferating cells

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

When are cdks active

A

Only when bound to cyclin

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

What allows progression into s phase

A

Cdk 4/6 binding to cyclin D

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

What effect does phosphorylation have on kinases

A

Activates them

17
Q

What effects does phosphatases have on kinases?

A

Turns them off

18
Q

How are cdks activated

A

Cyclin is produced and binds to cdk

Phosphorylation of Cdk-cyclin complex at inhibitory and activating sites of Cdk

Dephosphorylation by phosphatase which removes inhibitory phosphate from Cdk, activating it

19
Q

How does positive feedback work to increase the amount of active Cdk?

A

The activated Cdk activates more of the phosphatase to remove further inhibitory phosphates from Cdk-cyclin complexes

20
Q

How are cyclins turned off

A

Cyclin is ubiquitylated
Leads to destruction of cyclin
Cdk is inactive

21
Q

Which Cyclin-Cdk complex leads to the progression into G1 phase

A

Cyclin D- Cdk4/6 Complex

22
Q

Which Cyclin-Cdk complex leads to the progression into S phase

A

Cyclin E - Cdk2 Complex

23
Q

Which Cyclin-Cdk complex leads to the progression into M phase?

A

Cyclin A - Cdk2 Complex

24
Q

Which Cyclin-Cdk complex is formed after this?

A

Cyclin B - Cdk1 complex

25
Q

How are specific timing and direction given to cell cycle

A

Cdks become sequentially active and stimulate synthesis of genes

26
Q

How does the activity of cyclins allow the cell cycle to be cyclical

A

Cyclins are susceptible to degradation so they can be formed again

27
Q

Cancers replication rate

A

Embryonic cells have a faster rate of replication
Tumor cells-excessivedysregulated cell replication

28
Q

Retinoblastoma

A

Eye tumor suppressor
If rb protein missing or inactive there are issues with cell cycle progression
Rb acts as a brake in cell proliferation

29
Q

What does rb do in a resting cell

A

Rb sequesters a transcription factor in an inactive form commonly E2F family
The TF can’t turn on genes needed for cell cycle progression eg dna polymerase and thymidine kinase

30
Q

What does mitogen signalling do to rb in a proliferating cell

A

Activation of intracellular signalling through mitogens leads to production of G1-Cdk and G1/S-Cdk complexes

They phosphorylate the active Rb that is bound to TF, inactivating it which releases the TF

Target genes like DNA polymerase and thymidine kinase can now activate

31
Q

What is the function of p53

A

They arrest cells with damaged dna in G1

32
Q

P53

A

Recognizes double stranded breaks and activates kinases that phosphorylate p53
In absence of dna damage it is degraded

33
Q

What happens when dna damage is detected

A

If dna damage is detected active p53 gene binds to regulatory region on p21 gene
Transcription of p21 and dna occur
P21 family members are inhibitors of cyclin/Cdk complexes
Loss of function mutation in over 50% of humans

34
Q

Oncogenes

A

Ras-mutationally activated in cancers
Cyclin d1 over expressed in 50% of breast cancers
C-Myc overexpressed in many tumors
EGFR/HER2 mutationaly activated or over expressed in cancers

35
Q

Tumor suppressors

A

Rb loss of function mutations in 80% of small cell lung cancers
P53 loss of function mutations in over 50% of cancers

36
Q

How might over expression of c myc lead to aberrant cell cycling and cancer

A

Induces expression of cyclin D which drives inappropriate entry into G1-S phase

Pom (44 decks)

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