Brainscape's Knowledge GenomeTM

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


See full index

Biology 360 > Topic 7 - Cell cycle > Flashcards

Topic 7 - Cell cycle Flashcards

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

If conditions for growth are unfavourable, what can happen to stall the cell cycle?

A

Cell can stay in one of the G phases for a long time until conditions improve

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

DNA replication occurs during this phase of the cell cycle

A

S phase

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

Why is yeast a great model system to study the cell cycle?

A
  1. Replicates fast
  2. Small and easy to cultivate
  3. Easy to genetically manipulate
  4. Can be haploid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is advantageous about working with early stage embryos?

A

Because the cells don’t grow much in very early phases, the cell cycle is periodically “condensed”

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

In addition to sorting cells, FACS can be used to…

A

Determine which cells are in what phase of the cell cycle

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

What are 3 properties of the cell cycle control system?

A
  1. Binary - yes or no
  2. Irreversible, once u enter u cannot leave
  3. Highly adaptable and can be modified
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If Cdks are always present in the environment, why is only one Cdk active at a time?

A

Depends on activation by cyclin and whether or not inhibitory phosphate is present

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

What are the 2 functions of cyclin?

A
  1. Activate Cdks

2. Direct Cdks to target proteins - specify the Cdk’s functions

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

During which part of the cell cycle does the APC/C start to control the cell cycle?

A

Partway through M-phase (mitosis) - promotes anaphase

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

APC/C catalyzes the (process) of two main proteins

A
  1. Ubiquitylation/ubiquitination

2. Securin and S and M-cyclins

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

What protein binds to an inactive APC/C to activate it?

A

Cdc20

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

Describe the action of APC/C in anaphase

A

Degrades securin which is normally bound to separase, when securin is degraded separase is activated and it cuts the cohesin proteins which attach sister chromatids together during metaphase

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

Cyclins rise in the cell cycle during…

A

Late G1 phase until partway through M-phase

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

How do Cdks exert effects on target proteins?

A

Dephosphorylate them

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

What is a CKI?

A

A Cdk inhibitor protein

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

What is a key step in the transition of Cdk > APC/C control of the cell cycle?

A

All that was phosphorylated by Cdks will be dephosphorylated

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

Proteolysis (i.e. the breakdown of securin and Cdks) are controlled by this complex

A

SCF complex (Skp1, cullin, F-box protein)

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

What are the components of the SCF complex?

A

Skp1
Cullin
F-box protein

19
Q

Activation of the SCF complex happens when you want cyclins to be (active/inactive)

A

Active: they degrade CKIs (cdk inhibitors)

20
Q

The F-box of the SCF complex only recognizes proteins to be ubiquitylated if they are…

A

Phosphorylated

21
Q

Recognizing DNA damage will arrest the function of these cyclins in the cell cycle

A

G1/S-Cdk, S-Cdk, M-Cdk (All of them!)

22
Q

Unreplicated DNA will arrest the function of these cyclins

A

M-Cdk

23
Q

If the chromosome is unattached to the mitotic spindle, what cell cycle control protein will be inhibited?

A

APC/C

24
Q

To make sure the cell is in good condition to enter the cell cycle, the cell recognizes signals from the (intracellular/extracellular) environment

A

Both!

25
Q

M-Cdk inhibits this process

A

DNA rereplication

26
Q

How does Cdc25 activate Cdks?

A

Removes their inhibitory phosphate group

27
Q

Are the Cdk and APC/C systems ever active at the same time?

A

Never

28
Q

What aspects of accuracy are required when a cell is in the S-phase?

A
  1. No mistakes

2. Replicated only once - no rereplication

29
Q

Describe the prereplicative and preinitiation complexes of S-phase

A

Prereplicative: the protein complexes present while DNA is not being replicated - machinery is ready to go but DNA replication has not been initiated
Preinitiation: DNA helicase activated, accessory proteins at the ready for DNA to be transcribed

30
Q

The prereplicative complex of G1-phase is stimulated by…

A

APC/C - no DNA replication

31
Q

The preinitiation complex of S-phase is activated by…

A

S-Cdk

32
Q

The prereplicative complex of the G1 phase is inhibited by…

A

Cdk activity

33
Q

The role of helicase is to…

A

Unwind DNA

34
Q

DNA replication starts at…

A

Origin recognition complexes

35
Q

When is the origin recognition complex present on the DNA during the cell cycle?

A

Present the whole cycle

36
Q

How is the preinitiation complex activated?

A

Cdc6 associates with the origin recognition complex

37
Q

Active helicase is also bound to…

A

Cdt1

38
Q

Association of the prereplicative complex occurs when…

A

Cdt1 dissociates from helicase and Cdc6 dissociates from the ORC using ATP hydrolysis. This dissociation causes the recruitment of 2 helicases (forming the prereplicative complex)

39
Q

What enzyme activates helicase by phosphorylating it?

A

DDK

40
Q

How does S-Cdk contribute to the “activation” of the prereplication complex?

A

Phosphorylates initiator proteins which associate with DNA helicase and cause dissociation of the ORC complex

41
Q

Describe the recycling of the ORC machinery

A

There is no recycling! When it is all activated, it is phosphorylated and then when it dissociates it is dephosphorylated and degraded

i.e. ONLY USED ONCE

42
Q

When inactive and not associated to DNA, helicase and Cdt1 are also bound to…

A

Geminin

43
Q

What is geminin?

A

An inhibitor of Cdt1

Biology 360 (12 decks)

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