MMSC491: EXAM 2 2025 QUESTIONS
AND ANSWERS
1. Which of the following statements is false regarding the sources of genetic variation?
a. Most of the inherited changes in our DNA arise because of exposure to extracellular
mutagens, including sources of chemical mutagens
b. Significant chemical damage is sustained by DNA because of its proximity to water molecules
in our cells
c. Most of the inherited changes in our DNA arise because of unavoidable endogenous errors in
cellular mechanisms and harmful effects on certain natural molecules and atoms within our
cells
d. Errors in DNA replication and DNA repair are a major source of mutations in our cells -
ANS a. Most of the inherited changes in our DNA arise because of exposure to extracellular
mutagens, including sources of chemical mutagens
2. With reference to DNA repair, which of the following is false?
a. Crosslinking of bases on opposite DNA strands is especially problematic for cells because it
presents and obstacle to DNA replication and the replication fork is stalled
b. Double strand DNA breaks are a challenge for cells because if repair is not affected
immediately the ends can drift apart quickly making correct repair impossible
c. Crosslinking of bases on opposite DNA strands can be problematic for cells because it may
present an obstacle to transcription and the RNA polymerase is stalled
d. Repair of double stranded DNA breaks is easier in cells prior to DNA replication than after
DNA replication has occurred - ANS d. Repair of double stranded DNA breaks is easier in cells
prior to DNA replication than after DNA replication has occurred
1
Page
@COPYRIGHT BRAINBARTER 2025/2026
, 3. With reference to imprinting disorders, which of the following is false?
a. With the exception of abnormal chromosome segregation, imprinting disorders always result
from a deletion or inactivating mutation within or spanning the imprinted gene cluster
b. Angelman and prader willi syndrome are very different disorders but can be caused by
precisely the same large deletion at 15q11-q13
c. About one quarter of individuals with angelman syndrome lack a paternal chromosome 15
d. In some imprinting disorders, disease results from inappropriate biallelic expression of a gene
- ANS a. With the exception of abnormal chromosome segregation, imprinting disorders
always result from a deletion or inactivating mutation within or spanning the imprinted gene
cluster
4. Which of the following describes the non viral transfer of DNA, RNA, and oligonucleotides
into human or other animal cells? - ANS Transfection
5. Which of the following is an example of prevention treatment?
a. Organ transplant
b. Shunting elevated metabolite into side metabolic pathway
c. Reduction of susceptibility factor
d. Bone marrow transplant - ANS c. Reduction of susceptibility factor
6. Which disorders are more suitable for augmentation therapy?
a. Disorders in which the pathogenesis involves a positively harmful effect.
b. Recessive disorders
c. Disorders that do not involve a deficiency
d. Dominant disorders - ANS
7. Which of the following best describes cytokines?
a. Proteins released by animal cells that are involved in alerting the cellular immune
2
Page
system of viral infection of host cells
@COPYRIGHT BRAINBARTER 2025/2026
, b. Chemical messengers that help in intracellular signaling
c. Any of a class of glycoproteins produced by leukocytes for regulating immune
responses
d. A chemical substance produced in the body that controls and regulates the activity
of certain cells or organs - ANS b. Chemical messengers that help in intracellular signaling
8. Which of the following terms describes the ability to give rise to all cell types?
a. Monopotent
b. Multipotent
c. Pluripotent
d. Tripotent - ANS c. Pluripotent
9. Which of the following is NOT associated with gene silencing?
a. RNA interference
b. Inhibition of expression
c. RNA splicing
d. Genome editing - ANS c. RNA splicing
10. What stage of clinical trials includes several hundred patients, testing for safety and
efficacy?
a. phase I
b. phase II
c. phase III
d. phase IV - ANS b. phase II
11. What is the overall observed result of RNA interference?
3
a. Degraded RNA
Page
@COPYRIGHT BRAINBARTER 2025/2026
AND ANSWERS
1. Which of the following statements is false regarding the sources of genetic variation?
a. Most of the inherited changes in our DNA arise because of exposure to extracellular
mutagens, including sources of chemical mutagens
b. Significant chemical damage is sustained by DNA because of its proximity to water molecules
in our cells
c. Most of the inherited changes in our DNA arise because of unavoidable endogenous errors in
cellular mechanisms and harmful effects on certain natural molecules and atoms within our
cells
d. Errors in DNA replication and DNA repair are a major source of mutations in our cells -
ANS a. Most of the inherited changes in our DNA arise because of exposure to extracellular
mutagens, including sources of chemical mutagens
2. With reference to DNA repair, which of the following is false?
a. Crosslinking of bases on opposite DNA strands is especially problematic for cells because it
presents and obstacle to DNA replication and the replication fork is stalled
b. Double strand DNA breaks are a challenge for cells because if repair is not affected
immediately the ends can drift apart quickly making correct repair impossible
c. Crosslinking of bases on opposite DNA strands can be problematic for cells because it may
present an obstacle to transcription and the RNA polymerase is stalled
d. Repair of double stranded DNA breaks is easier in cells prior to DNA replication than after
DNA replication has occurred - ANS d. Repair of double stranded DNA breaks is easier in cells
prior to DNA replication than after DNA replication has occurred
1
Page
@COPYRIGHT BRAINBARTER 2025/2026
, 3. With reference to imprinting disorders, which of the following is false?
a. With the exception of abnormal chromosome segregation, imprinting disorders always result
from a deletion or inactivating mutation within or spanning the imprinted gene cluster
b. Angelman and prader willi syndrome are very different disorders but can be caused by
precisely the same large deletion at 15q11-q13
c. About one quarter of individuals with angelman syndrome lack a paternal chromosome 15
d. In some imprinting disorders, disease results from inappropriate biallelic expression of a gene
- ANS a. With the exception of abnormal chromosome segregation, imprinting disorders
always result from a deletion or inactivating mutation within or spanning the imprinted gene
cluster
4. Which of the following describes the non viral transfer of DNA, RNA, and oligonucleotides
into human or other animal cells? - ANS Transfection
5. Which of the following is an example of prevention treatment?
a. Organ transplant
b. Shunting elevated metabolite into side metabolic pathway
c. Reduction of susceptibility factor
d. Bone marrow transplant - ANS c. Reduction of susceptibility factor
6. Which disorders are more suitable for augmentation therapy?
a. Disorders in which the pathogenesis involves a positively harmful effect.
b. Recessive disorders
c. Disorders that do not involve a deficiency
d. Dominant disorders - ANS
7. Which of the following best describes cytokines?
a. Proteins released by animal cells that are involved in alerting the cellular immune
2
Page
system of viral infection of host cells
@COPYRIGHT BRAINBARTER 2025/2026
, b. Chemical messengers that help in intracellular signaling
c. Any of a class of glycoproteins produced by leukocytes for regulating immune
responses
d. A chemical substance produced in the body that controls and regulates the activity
of certain cells or organs - ANS b. Chemical messengers that help in intracellular signaling
8. Which of the following terms describes the ability to give rise to all cell types?
a. Monopotent
b. Multipotent
c. Pluripotent
d. Tripotent - ANS c. Pluripotent
9. Which of the following is NOT associated with gene silencing?
a. RNA interference
b. Inhibition of expression
c. RNA splicing
d. Genome editing - ANS c. RNA splicing
10. What stage of clinical trials includes several hundred patients, testing for safety and
efficacy?
a. phase I
b. phase II
c. phase III
d. phase IV - ANS b. phase II
11. What is the overall observed result of RNA interference?
3
a. Degraded RNA
Page
@COPYRIGHT BRAINBARTER 2025/2026
