MMSC490 ACTUAL EXAM SCRIPT 2026
QUESTIONS AND ANSWERS GRADED A+
◍ DNA polymerases can synthesize DNA:
a. de novo, by catalyzing the polymerization of free dNTPs.
b. by adding dNTPs to complementary dNTPs on a single-stranded
DNA.
c. by adding dNTPs to a hydroxyl group on the end of a growing
polynucleotide chain hydrogen-bonded to a strand of RNA.
d. by adding dNTPs to a hydroxyl group on the end of a growing
polynucleotide chain hydrogen-bonded to a strand of DNA. . Answer: d.
by adding dNTPs to a hydroxyl group on the end of a growing
polynucleotide chain hydrogen-bonded to a strand of DNA.
◍ In addition to synthesizing DNA, DNA polymerase I has a second
catalytic activity: it can
a. synthesize short RNA sequences.
b. synthesize short polypeptide sequences.
c. remove RNA primers.
d. ligate short segments of DNA together. . Answer: c. remove RNA
primers.
,◍ Which eukaryotic DNA polymerase replicates the leading strand in
the 5ʹ to 3ʹ direction?
a. α
b. ε
c. δ
d. γ . Answer: b. ε
◍ Free rotation of one cut DNA strand around one uncut strand is the
primary function of:
a. topoisomerase I.
b. topoisomerase II.
c. DNA helicase.
d. DNA polymerase. . Answer: a. topoisomerase I.
◍ The function of topoisomerase II is to:
a. resolve DNA tangles.
b. allow DNA to swivel and unwind.
c. allow daughter chr
d. all of the above . Answer: d. all of the above
◍ Autonomously replicating sequences are:
a. yeast plasmids.
,b. yeast telomeres.
c. bacterial plasmids.
d. yeast origins of replication. . Answer: d. yeast origins of replication.
◍ Telomeres are the:
a. midpoints of chromosomes.
b. microtubule attachment points on chromosomes. c. end-sequences of
chromosomes.
d. enzyme complexes that complete DNA replication. . Answer: c. end-
sequences of chromosomes.
◍ Point mutations in DNA result from:
a. incorporation of incorrect bases during replication.
b. changes as a result of chemical exposure.
c. changes as a result of radiation exposure.
d. All of the above . Answer: d. All of the above
◍ The most common cause of skin cancer is damage to DNA by:
a. infrared light.
b. ultraviolet light.
c. γ radiation.
d. β particle radiation. . Answer: b. ultraviolet light.
, ◍ Pyrimidine dimers:
a. block DNA replication and transcription.
b. can be repaired by photoreactivation.
c. can be repaired by nucleotide-excision repair.
d. All of the above . Answer: d. All of the above
◍ Cultured cells from xeroderma pigmentosum patients were unable to
carry out:
a. base-excision repair.
b. nucleotide-excision repair.
c. synthesis of melanin.
d. DNA synthesis. . Answer: b. nucleotide-excision repair.
◍ E. coli DNA polymerase V:
a. is induced in response to high temperatures.
b. recognizes thymidine dimers and inserts nucleotides on the opposite
strand.
c. has a low frequency of errors.
d. is activated during transcription. . Answer: b. recognizes thymidine
dimers and inserts nucleotides on the opposite strand.
◍ Site-specific recombination:
QUESTIONS AND ANSWERS GRADED A+
◍ DNA polymerases can synthesize DNA:
a. de novo, by catalyzing the polymerization of free dNTPs.
b. by adding dNTPs to complementary dNTPs on a single-stranded
DNA.
c. by adding dNTPs to a hydroxyl group on the end of a growing
polynucleotide chain hydrogen-bonded to a strand of RNA.
d. by adding dNTPs to a hydroxyl group on the end of a growing
polynucleotide chain hydrogen-bonded to a strand of DNA. . Answer: d.
by adding dNTPs to a hydroxyl group on the end of a growing
polynucleotide chain hydrogen-bonded to a strand of DNA.
◍ In addition to synthesizing DNA, DNA polymerase I has a second
catalytic activity: it can
a. synthesize short RNA sequences.
b. synthesize short polypeptide sequences.
c. remove RNA primers.
d. ligate short segments of DNA together. . Answer: c. remove RNA
primers.
,◍ Which eukaryotic DNA polymerase replicates the leading strand in
the 5ʹ to 3ʹ direction?
a. α
b. ε
c. δ
d. γ . Answer: b. ε
◍ Free rotation of one cut DNA strand around one uncut strand is the
primary function of:
a. topoisomerase I.
b. topoisomerase II.
c. DNA helicase.
d. DNA polymerase. . Answer: a. topoisomerase I.
◍ The function of topoisomerase II is to:
a. resolve DNA tangles.
b. allow DNA to swivel and unwind.
c. allow daughter chr
d. all of the above . Answer: d. all of the above
◍ Autonomously replicating sequences are:
a. yeast plasmids.
,b. yeast telomeres.
c. bacterial plasmids.
d. yeast origins of replication. . Answer: d. yeast origins of replication.
◍ Telomeres are the:
a. midpoints of chromosomes.
b. microtubule attachment points on chromosomes. c. end-sequences of
chromosomes.
d. enzyme complexes that complete DNA replication. . Answer: c. end-
sequences of chromosomes.
◍ Point mutations in DNA result from:
a. incorporation of incorrect bases during replication.
b. changes as a result of chemical exposure.
c. changes as a result of radiation exposure.
d. All of the above . Answer: d. All of the above
◍ The most common cause of skin cancer is damage to DNA by:
a. infrared light.
b. ultraviolet light.
c. γ radiation.
d. β particle radiation. . Answer: b. ultraviolet light.
, ◍ Pyrimidine dimers:
a. block DNA replication and transcription.
b. can be repaired by photoreactivation.
c. can be repaired by nucleotide-excision repair.
d. All of the above . Answer: d. All of the above
◍ Cultured cells from xeroderma pigmentosum patients were unable to
carry out:
a. base-excision repair.
b. nucleotide-excision repair.
c. synthesis of melanin.
d. DNA synthesis. . Answer: b. nucleotide-excision repair.
◍ E. coli DNA polymerase V:
a. is induced in response to high temperatures.
b. recognizes thymidine dimers and inserts nucleotides on the opposite
strand.
c. has a low frequency of errors.
d. is activated during transcription. . Answer: b. recognizes thymidine
dimers and inserts nucleotides on the opposite strand.
◍ Site-specific recombination:
