MMSC 490 FE EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2025/2026
The eukaryotic cell cycle is composed of four phases in the following order:
a. G1; S; G2; M
b. G1; G2; S; M
c. G1; M; G2; S
d. S; G1; G2; M - Answers A
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 - Answers C
In a typical cycling mammalian cell, _______ of the cell cycle is spent in interphase.
a. 99%
b. 95%
c. 75%
d. 50% - Answers B
Cell cycles of early embryonic animal cells are unusual because they have
a. no G1 or G2.
b. an elongated G1 and G2.
c. a short S.
d. a much shortened M. - Answers A
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 - Answers B
Which of the following represents the amount of DNA in a typical G2 cell?
a. n
b. 2n
c. 4n
d. 8n - Answers C
The G1 checkpoint in budding yeast cells is called
a. START.
b. the restriction point.
c. the decision point.
d. the G1/S boundary. - Answers A
The G1 checkpoint in animal cells is called
a. START.
b. the restriction point.
c. the decision point.
d. the G1/S boundary. - Answers B
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 - Answers C
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 - Answers D
Maturation promotion factor (MPF), discovered by Masui and Markert, is the factor that
a. is missing in the cdc2 mutant in yeast.
b. induces entry into meiosis when injected into frog oocytes.
c. fluctuates in amount during early cleavages of sea urchin eggs.
d. fluctuates in amount during the cell cycle of mammalian cells. - Answers B
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. - Answers D
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. - Answers C
Studies on cell cycle mutants in budding and fission yeasts demonstrated that cdc2 and cdc28
both encode a
a. protein kinase.
b. protein phosphatase.
c. ubiquinating enzyme.
d. growth factor. - Answers A
Two sea urchin proteins were named cyclin A and B because, during the embryonic cell cycle,
they were periodically
a. activated and inactivated by phosphorylation and dephosphorylation.
, b. synthesized and degraded.
c. bound and released by another protein.
d. ubiquitylated and non-ubiquitylated. - Answers B
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. - Answers B
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. - Answers A
Which cyclin(s) is/are required to pass the G1 restriction point in animal cells?
a. Cyclin A
b. Cyclin A and Cyclin B
c. Cyclin D
d. Cyclin D and Cyclin E - Answers C
Passage of animal cells through the cell cycle is regulated primarily by
a. the availability of nutrients.
b. intracellular second messengers.
c. extracellular growth factors.
d. direct cell surface interactions. - Answers C
The retinoblastoma protein (Rb) binds to and inhibits
The eukaryotic cell cycle is composed of four phases in the following order:
a. G1; S; G2; M
b. G1; G2; S; M
c. G1; M; G2; S
d. S; G1; G2; M - Answers A
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 - Answers C
In a typical cycling mammalian cell, _______ of the cell cycle is spent in interphase.
a. 99%
b. 95%
c. 75%
d. 50% - Answers B
Cell cycles of early embryonic animal cells are unusual because they have
a. no G1 or G2.
b. an elongated G1 and G2.
c. a short S.
d. a much shortened M. - Answers A
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 - Answers B
Which of the following represents the amount of DNA in a typical G2 cell?
a. n
b. 2n
c. 4n
d. 8n - Answers C
The G1 checkpoint in budding yeast cells is called
a. START.
b. the restriction point.
c. the decision point.
d. the G1/S boundary. - Answers A
The G1 checkpoint in animal cells is called
a. START.
b. the restriction point.
c. the decision point.
d. the G1/S boundary. - Answers B
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 - Answers C
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 - Answers D
Maturation promotion factor (MPF), discovered by Masui and Markert, is the factor that
a. is missing in the cdc2 mutant in yeast.
b. induces entry into meiosis when injected into frog oocytes.
c. fluctuates in amount during early cleavages of sea urchin eggs.
d. fluctuates in amount during the cell cycle of mammalian cells. - Answers B
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. - Answers D
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. - Answers C
Studies on cell cycle mutants in budding and fission yeasts demonstrated that cdc2 and cdc28
both encode a
a. protein kinase.
b. protein phosphatase.
c. ubiquinating enzyme.
d. growth factor. - Answers A
Two sea urchin proteins were named cyclin A and B because, during the embryonic cell cycle,
they were periodically
a. activated and inactivated by phosphorylation and dephosphorylation.
, b. synthesized and degraded.
c. bound and released by another protein.
d. ubiquitylated and non-ubiquitylated. - Answers B
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. - Answers B
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. - Answers A
Which cyclin(s) is/are required to pass the G1 restriction point in animal cells?
a. Cyclin A
b. Cyclin A and Cyclin B
c. Cyclin D
d. Cyclin D and Cyclin E - Answers C
Passage of animal cells through the cell cycle is regulated primarily by
a. the availability of nutrients.
b. intracellular second messengers.
c. extracellular growth factors.
d. direct cell surface interactions. - Answers C
The retinoblastoma protein (Rb) binds to and inhibits
