Cell cycle Flashcards
Regulate decision to divide
– Am I big enough?
– Are there enough nutrients?
– Have I received the right
signal?
A) G2
B) G1
C) S phase
D) M
B
Is all DNA replicated? Is all DNA damage repaired?
A) G2
B) G1
C) S phase
D) M
A
Are all chromosomes properly attached to the mitotic spindle?
A) G2
B) G1
C) S phase
D) M
D
Place the different phases of the cell cycle
in a correct order. Since the cell cycle is
circular, the starting point is arbitrary (we can
start with any phase).
A. G2, M, G1, S
B. G1, M, G2, S
C. M, G1, G2, S
D. M, G2, G1, S
E. G1, G2, M, S
A
Progression through
the cell cycle (passing checkpoints) depends on ________and _________kinases
cyclins
and cyclin-dependent protein
MPF kinase phosphorylates?
a. Lamins (nuclear matrix- nuclear breakdown)
b. Microtubule associated proteins (MT dynamics)
c. Chromatin proteins (Condensation/separation
d) all of the above
D
How can the cell cycle be stopped?
A) the cell cycle can
be stopped by binding a protein inhibitor to active
complex, thereby preventing its kinase activity.
B) activating CDK complexes
C) degrading cyclins
D) A and C
D
Which of the following does NOT inhibit or end the
activity of a Cdk?
A. addition of a phosphate to Cdk
B. degradation of a cyclin
C. synthesis of a Cdk inhibitor
D. The activity of the cdc 25 phosphatase
E. All of the above (A, B, C or D) inhibit or end the activity
of Cdk, so no answer is correct.
D
Rb prevents transcription of
cell division genes by
________
factors.
A) sequestering transcription
B)Phosphorylation
C) cell division
A
P53 is a regulator muted in
A) many cancers
B) protein regulaions
C) RB proteins
D phosphorylation
A
When P53 is __________ (1), it _________ (2) to
activate transcription of a gene that leads to cell
cycle ______ (3)
A. dephosphorylated (1), binds to a promoter (2),
progression (3)
B. phosphorylated (1), binds to a promoter (2),
arrest (3)
C. phosphorylated (1), releases a transcription
factor (2), progression (3)
D. phosphorylated (1), releases a transcription
factor (2), arrest (3)
E. dephosphorylated (1), releases a transcription
factor (2), progression (3)
B
Q4: What is the correct order for the stages of M phase?
A. prometaphase, metaphase, prophase, telophase,
anaphase.
B. prometaphase, metaphase, prophase, anaphase,
telophase
C. prophase, prometaphase, metaphase, anaphase,
telophase
D. telophase, anaphase, prometaphase, metaphase,
prophase
E. anaphase, telophase, prometaphase, metaphase
C
Which of the following is true about the regulation produced by M-Cdk?
A. An activating kinase phosphorylates M-Cdk only after cyclin levels have
accumulated, and this phosphorylation leads to immediate activation of the
M-Cdk.
B. The enzymatic activity of Cdc25 phosphatase is turned off only after
cyclin has accumulated.
C. Cyclin must be degraded before M-Cdk becomes active.
D. Lots of Cdc25 phosphatase is activated quickly by M-Cdk after this M-
Cdk has been activated, and this new
D
Sister chromatids are held together by
A) MItosis
B) Chohesin rings
C) lamins
D) membrane bound proteins
B
Which of the following statements is correct?
A. Centrosomes are replicated during M phase.
B. Two sister chromatids arise by replication of the DNA of
the same chromosome but are no longer paired with each other at the
metaphase plate.
C. Non kinetochore microtubules assemble from one end to the other and are
therefore continuous from one spindle pole to the other.
D. Microtubule polymerization and depolymerization
and microtubule motor proteins are all required for DNA
replication.
E. Microtubules nucleate at the centrosomes and then
connect to the kinetochores, which are structures at the
centromere regions of chromosomes.
E
Activation of Anaphase-promoting complex (APC)
triggers separation of the chromatids because it
triggers degradation of____, activating separase
A) Seperase
B) securin
C) APC
D) M-cyclin
B
Which motor protein is likely to generate
the sliding force (1) and which motor protein is
likely to generate the pulling force (2) for
Anaphase B?
A. Kinesins for (1) and dyneins for (2)
B. Dyneins for (1) and kinesins for (2)
C. Dyneins for both (1) and (2)
D. Kinesins for both (1) and (2)
E. Myosins for both (1) and (2)
A
Mitogens stimulate cell division by
– Binding receptors
– Activating signal transduction pathways
– Release the ‘brakes’ on the cell cycle – usually the brake
at the G1 to S transition.
– For instance, Platelet-Derived Growth Factor (PDGF)
stimulates division of cells at a wound to repair the
damaged tissue.
Growth factors stimulate cells
to grow larger
Bind receptors
-Activate signal transduction
pathways (eg, Akt-Tor pathway)
-Cause cell growth (increase in cell
mass) without cell division.
-In early embryogenesis, cells
divide without growth and get
smaller compared with the
fertilized egg.
Fig. 18-36
Why do cells undergo apoptosis?
-Developing animals
Sculpting body plan (e.g., digits on paws, hands, feet)
Neuronal: Selection for cells with best connections
-Adults
Tissues/organs are maintained at a size
Replacement: “old” cells may be more prone to problems
Infected cells can be eliminated
Pre-Cancer cells can be eliminated
Apoptosis
A) cell burst and spills contents
B) Phagocytic cells can engulf intact dead
cell before contents spill out
C) cell shrinks and condense
D) A and B, but not C
E) B and C, but not A
E
Cell survival rather than apoptosis is
promoted (increased) when
A. transcription of the Bcl2 gene is increased in
response to signaling from survival factor
receptors.
B. The activities of Bax and Bak are inhibited.
C. The activities of Bax and Bak are stimulated.
D. A and B increase cell survival.
E. A and C increase cell survival.
D
The cell cycle component whose protein levels do not vary, but which instead interacts with a
component that does vary in level to trigger progression to the next phase of the cell cycle, is
A. Cyclin-dependent kinase.
B. Wee1.
C. Cdc6.
D. p27.
E. Cyclin
A
At what phase of the cell cycle would cells typically enter Go or terminally differentiate?
A. M
B. G1
C. G2
D. S
E. Cells could enter Go or terminally differentiate in any of these phases (A, B, C or D)
B
