MMSC 490 Exam 3 Questions and Answers Fully Solved Latest Update 2025-2026
The length of time it takes for the cells labeled during DNA synthesis to begin to enter mitosis
is a good estimate of the length of the _______ phase(s).
a. G1
b. S
c. G2
d. M - Answersc. G2
In a typical cycling mammalian cell, _______ of the cell cycle is spent in interphase.
a. 99%
b. 95%
c. 75%
d. 50% - Answersb. 95%
The number of cells in the different phases of a population can be determined most easily by
using a(n) _______ to measure the amount of DNA per cell in a large sample of cells.
a. scintillation counter
b. flow cytometer
c. fluorescence microscope
d. phase-contrast microscope after autoradiography - Answersb. flow cytometer
Which of the following represents the amount of DNA in a typical G2 cell?
a. n
b. 2n
c. 4n
d. 8n - Answersc. 4n
The G1 checkpoint in budding yeast cells is called
a. START
,b. the restriction point
c. the decision point
d. the G1/S boundary - Answersa. START
The G1 checkpoint in animal cells is called
a. START
b. the restriction point
c. the decision point
d. the G1/S boundary - Answersb. the restriction point
Skin fibroblasts arrested in G0 are stimulated near a wound to enter G1 by _______ growth
factor.
a. epidermal
b. fibroblast
c. platelet-derived
d. keratinocyte - Answersc. platelet-derived
The G2 checkpoint prevents entry into _______ if _______.
a. G1; DNA synthesis is not complete and/or DNA is damaged
b. S; DNA synthesis is not complete and/or DNA is damaged
c. G2; DNA synthesis is not complete and/or DNA is damaged
d. M; DNA synthesis is not complete and/or DNA is damaged - Answersd. M; DNA synthesis is
not complete and/or DNA is damaged
MPF is a:
a. monomeric protein kinase
b. dimer of two molecules of Cdk1
c. dimer of Cdk1 and cyclin A
d. dimer of Cdk1 and cyclin B - Answersd. dimer of Cdk1 and cyclin B
MPF is a general regulator of the transition from
, a. G1 to S
b. S to G2
c. G2 to M
d. metaphase to anaphase - Answersc. G2 to M
To become active, Cdk1 must:
a. bind cyclin
b. bind cyclin and be phosphorylated on tyrosine 15 and threonines 14 and 161
c. bind cyclin and be phosphorylated on tyrosine 15, and be dephosphorylated on threonines 14
and 161
d. bind cyclin and be phosphorylated on threonine 161, and be dephosphorylated on threonine
14
and tyrosine 15 - Answersd. bind cyclin and be phosphorylated on threonine 161, and be
dephosphorylated on threonine 14
and tyrosine 15
Cdks bind to cyclin and are activated by:
a. phosphorylation by Wee1
b. dephosphorylation by Cdc25 protein phosphatase
c. the binding of Ink4
d. the binding of Cip - Answersb. dephosphorylation by Cdc25 protein phosphatase
The retinoblastoma protein (Rb) binds to and inhibits:
a. transcription factor E2F
b. oncogenes
c. cyclin-dependent kinase
d. p53 - Answersa. transcription factor E2F
Polar microtubules:
a. overlap in the center of the spindle
The length of time it takes for the cells labeled during DNA synthesis to begin to enter mitosis
is a good estimate of the length of the _______ phase(s).
a. G1
b. S
c. G2
d. M - Answersc. G2
In a typical cycling mammalian cell, _______ of the cell cycle is spent in interphase.
a. 99%
b. 95%
c. 75%
d. 50% - Answersb. 95%
The number of cells in the different phases of a population can be determined most easily by
using a(n) _______ to measure the amount of DNA per cell in a large sample of cells.
a. scintillation counter
b. flow cytometer
c. fluorescence microscope
d. phase-contrast microscope after autoradiography - Answersb. flow cytometer
Which of the following represents the amount of DNA in a typical G2 cell?
a. n
b. 2n
c. 4n
d. 8n - Answersc. 4n
The G1 checkpoint in budding yeast cells is called
a. START
,b. the restriction point
c. the decision point
d. the G1/S boundary - Answersa. START
The G1 checkpoint in animal cells is called
a. START
b. the restriction point
c. the decision point
d. the G1/S boundary - Answersb. the restriction point
Skin fibroblasts arrested in G0 are stimulated near a wound to enter G1 by _______ growth
factor.
a. epidermal
b. fibroblast
c. platelet-derived
d. keratinocyte - Answersc. platelet-derived
The G2 checkpoint prevents entry into _______ if _______.
a. G1; DNA synthesis is not complete and/or DNA is damaged
b. S; DNA synthesis is not complete and/or DNA is damaged
c. G2; DNA synthesis is not complete and/or DNA is damaged
d. M; DNA synthesis is not complete and/or DNA is damaged - Answersd. M; DNA synthesis is
not complete and/or DNA is damaged
MPF is a:
a. monomeric protein kinase
b. dimer of two molecules of Cdk1
c. dimer of Cdk1 and cyclin A
d. dimer of Cdk1 and cyclin B - Answersd. dimer of Cdk1 and cyclin B
MPF is a general regulator of the transition from
, a. G1 to S
b. S to G2
c. G2 to M
d. metaphase to anaphase - Answersc. G2 to M
To become active, Cdk1 must:
a. bind cyclin
b. bind cyclin and be phosphorylated on tyrosine 15 and threonines 14 and 161
c. bind cyclin and be phosphorylated on tyrosine 15, and be dephosphorylated on threonines 14
and 161
d. bind cyclin and be phosphorylated on threonine 161, and be dephosphorylated on threonine
14
and tyrosine 15 - Answersd. bind cyclin and be phosphorylated on threonine 161, and be
dephosphorylated on threonine 14
and tyrosine 15
Cdks bind to cyclin and are activated by:
a. phosphorylation by Wee1
b. dephosphorylation by Cdc25 protein phosphatase
c. the binding of Ink4
d. the binding of Cip - Answersb. dephosphorylation by Cdc25 protein phosphatase
The retinoblastoma protein (Rb) binds to and inhibits:
a. transcription factor E2F
b. oncogenes
c. cyclin-dependent kinase
d. p53 - Answersa. transcription factor E2F
Polar microtubules:
a. overlap in the center of the spindle
