D103 Final Actual Exam Questions and
CORRECT Answers
Gap phases - CORRECT ANSWER✔✔- Phases that allow time for growth and ensure
suitable environment before proceeding to S and M phases
G0 - CORRECT ANSWER✔✔- state of paused cell division that occurs during G1
G1 - CORRECT ANSWER✔✔- Phase of growth 1
S - CORRECT ANSWER✔✔- Phase of chromosomal duplication
G2 - CORRECT ANSWER✔✔- Phase of growth 2
M - CORRECT ANSWER✔✔- Phase of mitosis (nuclear division) and cytokinesis (cell
division)
flow cytometry - CORRECT ANSWER✔✔- uses lasers to analyze labeled cell contents as
they pass through a capillary
Cdk - CORRECT ANSWER✔✔- Cyclin dependent kinases that require cyclin for protein
kinase activity
Cyclins - CORRECT ANSWER✔✔- Proteins that activate and direct CDKs to their specific
targets; synthesized and degraded each cycle
what promotes cyclin synthesis? degradation? - CORRECT ANSWER✔✔- synthesis
promoted by transcription; degradation promoted by ubiquitin signals from APC/C (anaphase
promoting complex)
What would happen if cyclins could be synthesized by not degraded? - CORRECT
ANSWER✔✔- cell will become stuck at whatever phase it is in during cell cycle
,CAK - CORRECT ANSWER✔✔- Cdk activator kinase that activates Cdks by
phosphorylation
CKI - CORRECT ANSWER✔✔- Cdk inhibitor kinase that inactivates Cdks
Anaphase promoting complex (APC/C) - CORRECT ANSWER✔✔- Ubiquitin ligase
enzyme that polyubiquitinates specific target proteins for destruction
Mitogens - CORRECT ANSWER✔✔- growth factors whose presence determines whether or
not cell will enter S phase
What happens if mitogens are withdrawn before restriction point? after restriction point? -
CORRECT ANSWER✔✔- withdrawal of mitogens before will stimulate cell-cycle entry;
while withdrawal of mitogens after restriction point does not affect cell cycle progression
(point of no return)
Restriction point - CORRECT ANSWER✔✔- Point at which cell decides to divide or enter
quiescence
(transition between G1 to S phase)
3 major types of check point in cell cycle - CORRECT ANSWER✔✔- 1. restriction point
2. DNA damage check point
3. spindle assembly check point
DNA damage check point - CORRECT ANSWER✔✔- - stops cell cycle when DNA damage
has been detected or unfaithful duplication occurs
- CKI can temporarily inhibit M-CDK cyclin
spindle assembly checkpoint - CORRECT ANSWER✔✔- - important checkpoint in pro-
metaphase that allows time for chromosomes attachment to MTs and alignment at metaphase
plate
- if chromosomes are not properly attached, the checkpoint prevents exit from mitosis
, ATM/ ATR kinases - CORRECT ANSWER✔✔- kinases activated by DNA damage, activate
Chk kinase
Chk kinase - CORRECT ANSWER✔✔- phosphorylates p53 in response to DNA damage
p53 - CORRECT ANSWER✔✔- - transcription factor that promotes transcription of genes
that stop cell cycle, DNA repair and apoptosis
- targets include p21 and p27
how is p53 synthesized? - CORRECT ANSWER✔✔- MDM2 ubiquitin ligase controls
synthesis and destruction
How is p53 activated? - CORRECT ANSWER✔✔- DNA damage activates ATM/ATK
kinases, which activate Chk kinases, which phosphorylate p53
Interphase - CORRECT ANSWER✔✔- Collective term for G1, S, and G2 phases
How do we monitor cells undergoing the cell cycle? - CORRECT ANSWER✔✔- -
Microscopy; use of specific labels, such as tagging newly synthesized DNA
- Flow cytometry
Cell-cycle control system - CORRECT ANSWER✔✔- system that triggers events in a set
sequence (similar to a timer)
Cyclin-Cdk complex - CORRECT ANSWER✔✔- Complex formed by cyclin and Cdk
proteins
How is cyclin-CDK complex activity regulated? - CORRECT ANSWER✔✔- - changes in
cyclin levels
- complex phosphorylation/ dephosphorylation by wee1 and/ or cdc25
- reversible binding of regulatory proteins (ex: p21 and p27)
CORRECT Answers
Gap phases - CORRECT ANSWER✔✔- Phases that allow time for growth and ensure
suitable environment before proceeding to S and M phases
G0 - CORRECT ANSWER✔✔- state of paused cell division that occurs during G1
G1 - CORRECT ANSWER✔✔- Phase of growth 1
S - CORRECT ANSWER✔✔- Phase of chromosomal duplication
G2 - CORRECT ANSWER✔✔- Phase of growth 2
M - CORRECT ANSWER✔✔- Phase of mitosis (nuclear division) and cytokinesis (cell
division)
flow cytometry - CORRECT ANSWER✔✔- uses lasers to analyze labeled cell contents as
they pass through a capillary
Cdk - CORRECT ANSWER✔✔- Cyclin dependent kinases that require cyclin for protein
kinase activity
Cyclins - CORRECT ANSWER✔✔- Proteins that activate and direct CDKs to their specific
targets; synthesized and degraded each cycle
what promotes cyclin synthesis? degradation? - CORRECT ANSWER✔✔- synthesis
promoted by transcription; degradation promoted by ubiquitin signals from APC/C (anaphase
promoting complex)
What would happen if cyclins could be synthesized by not degraded? - CORRECT
ANSWER✔✔- cell will become stuck at whatever phase it is in during cell cycle
,CAK - CORRECT ANSWER✔✔- Cdk activator kinase that activates Cdks by
phosphorylation
CKI - CORRECT ANSWER✔✔- Cdk inhibitor kinase that inactivates Cdks
Anaphase promoting complex (APC/C) - CORRECT ANSWER✔✔- Ubiquitin ligase
enzyme that polyubiquitinates specific target proteins for destruction
Mitogens - CORRECT ANSWER✔✔- growth factors whose presence determines whether or
not cell will enter S phase
What happens if mitogens are withdrawn before restriction point? after restriction point? -
CORRECT ANSWER✔✔- withdrawal of mitogens before will stimulate cell-cycle entry;
while withdrawal of mitogens after restriction point does not affect cell cycle progression
(point of no return)
Restriction point - CORRECT ANSWER✔✔- Point at which cell decides to divide or enter
quiescence
(transition between G1 to S phase)
3 major types of check point in cell cycle - CORRECT ANSWER✔✔- 1. restriction point
2. DNA damage check point
3. spindle assembly check point
DNA damage check point - CORRECT ANSWER✔✔- - stops cell cycle when DNA damage
has been detected or unfaithful duplication occurs
- CKI can temporarily inhibit M-CDK cyclin
spindle assembly checkpoint - CORRECT ANSWER✔✔- - important checkpoint in pro-
metaphase that allows time for chromosomes attachment to MTs and alignment at metaphase
plate
- if chromosomes are not properly attached, the checkpoint prevents exit from mitosis
, ATM/ ATR kinases - CORRECT ANSWER✔✔- kinases activated by DNA damage, activate
Chk kinase
Chk kinase - CORRECT ANSWER✔✔- phosphorylates p53 in response to DNA damage
p53 - CORRECT ANSWER✔✔- - transcription factor that promotes transcription of genes
that stop cell cycle, DNA repair and apoptosis
- targets include p21 and p27
how is p53 synthesized? - CORRECT ANSWER✔✔- MDM2 ubiquitin ligase controls
synthesis and destruction
How is p53 activated? - CORRECT ANSWER✔✔- DNA damage activates ATM/ATK
kinases, which activate Chk kinases, which phosphorylate p53
Interphase - CORRECT ANSWER✔✔- Collective term for G1, S, and G2 phases
How do we monitor cells undergoing the cell cycle? - CORRECT ANSWER✔✔- -
Microscopy; use of specific labels, such as tagging newly synthesized DNA
- Flow cytometry
Cell-cycle control system - CORRECT ANSWER✔✔- system that triggers events in a set
sequence (similar to a timer)
Cyclin-Cdk complex - CORRECT ANSWER✔✔- Complex formed by cyclin and Cdk
proteins
How is cyclin-CDK complex activity regulated? - CORRECT ANSWER✔✔- - changes in
cyclin levels
- complex phosphorylation/ dephosphorylation by wee1 and/ or cdc25
- reversible binding of regulatory proteins (ex: p21 and p27)
