Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry + Cell Bio > Week 11 - Cell Cycle > Flashcards

Week 11 - Cell Cycle Flashcards

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

What are the steps in the cell cycle

A

(G1->S->G2)*->M
*interphase

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

What are the stages of M phase

A

Prophase, prometaphase, metaphase, anaphase, telophase

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

What happens during G1

A

Cell is metabolically active and growing

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

What happens during S phase

A

DNA replication

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

What happens during G2

A

Cell growth continues and proteins synthesised in preparation for mitosis

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

What acts as a control point between G1 and S phase

A

START/restriction point

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

What happens when appropriate growth factors aren’t present in G1

A

The cell enters G0

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

What causes progression from G2 to S phase

A

Hormonal stimulation

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

Name when all 4 cell cycle checkpoints occur

A

Restriction point
DNA damage in S phase
DNA damage in G2
Spindle assembly during M

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

How is it ensured that the genome is only replicated once per cell cycle

A

MCM proteins are displaced from ORC so that replication cannot happen until after mitosis

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

Which 2 ways can we analyse the cell cycle

A

Flow cyclometer or fluorescence activated cell sorter

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

What three experiments contributed to identifying cell cycle regulatory molecules

A

Studies of frog oocytes
Genetic analysis of yeast
Protein synthesis in sea urchin embryos

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

What did the study of frog oocytes show

A

Maturation protein factor was responsible for entering a cell into M phase from G2

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

What did the analysis of yeast show us

A

cdc genes are needed to pass through START and entry into mitosis; they encode protein kinases

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

What is the human equivalent of cdc

A

Cdk1

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

What did the sea urchin experiment show

A

Cyclins accumulate in interphase and rapidly degrade at the end of mitosis

17
Q

What was deduced when these experiments were merged

A

Cyclin A provides transition into M phase and MPF was a mix of Cdk1 and cyclin B
Without cyclin B being bound to Cdk1 proteins can’t be phosphorylated and cell cycle doesn’t progress

18
Q

When is Cdk1 active and inactive

A

Active when it’s dephosphorylised and inactive when it becomes phosphorylised

19
Q

What happens when cyclin B is degraded

A

Cell exits mitosis and undergoes cytokinesis and returns to interphase

20
Q

What 4 mechanisms regulate activity of Cdks

A

Association to cyclin partners
Activation of complexes needs phosphorylation of threonine at position 160
Inhibitory phosphorylation catalysed by Wee1
Binding of cdk inhibitors

21
Q

How are D type cyclins important

A

Provide one link between growth factor signalling and cell cycle progression

22
Q

What pathway do growth factors stimulate cyclin D1 synthesis through

A

Ras/Raf/MEK/ERK pathway

23
Q

What happens to the cell cycle and cyclin D1 if growth factors are present through G1

A

Cdk4,6/cyclin D1 complexes will drive cells through the restriction point

24
Q

What can be caused by cyclin D1 regulatory defects

A

Cancer

25
Q

What does Rb gene do

A

Is as a tumour suppressor gene by slowing down the progression of the cell cycle

26
Q

How does Rb work

A

In G0 or early G1, Rb binds to E2F transcription factors to suppress gene expression involved in cell cycle progression

27
Q

How is Rb dissociated

A

It is phosphorylated by cdk4,6/cyclin D as the cell passes the restriction point

28
Q

What happens after Rb is phosphorylated

A

E2F stimulates cdk2/cyclin E which leads to activation of MCM helicase, initiating DNA replication

29
Q

Which protein kinases mediate cell cycle arrest

A

ATM and ATR

30
Q

When are ATM and ATR activated

A

When DNA is damaged

31
Q

What does ATM recognise

A

Double strand breaks

32
Q

What does ATR recognise

A

Single stranded or unreplicated DNA

33
Q

What does ATM and ATK do after recognising defects

A

Phosphorylate Chk1 and Chk2

34
Q

What do Chk1 and Chk2 do

A

Phosphorylate cdc25 to inhibit it and cause cell cycle arrest since cdk1 and cdk2 become inhibited
Cdk1 causes arrest in G2
Cdk2 causes arrest in G1 and S

Biochemistry + Cell Bio (10 decks)

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