BIOL 5333 Advanced pathophysiology
(TWU) QUESTIONS AND
CORRECT ANSWERS)
180 multiple-choice and review questions spanning core advanced biological concepts,
accompanied by the correct answer key.
Part 1: Exam Guide Questions
Section 1: Advanced Molecular Biology & Gene Regulation (Questions 1–35)
1. Which of the following structural motifs is most commonly associated with sequence-
specific DNA binding by eukaryotic transcription factors?
A) Beta-barrel
B) Zinc finger
C) Alpha-sheet
D) Pleated domain
Answer: B
2. During DNA replication, which enzyme is responsible for relieving the torsional strain
ahead of the replication fork?
A) DNA Helicase
B) DNA Ligase
C) Topoisomerase
D) Primase
Answer: C
3. What is the primary function of the TATA-binding protein (TBP)?
A) To terminate transcription
B) To recruit RNA Polymerase II to the promoter
C) To facilitate tRNA charging
D) To catalyze mRNA splicing
Answer: B
4. Which modification to histone tails is most tightly coupled with active gene
transcription?
A) Methylation of H3K9
B) Acetylation of Lysine residues
C) Ubiquitination of H2A
D) Phosphorylation of Serine 10 only
Answer: B
5. The phenomenon where a single pre-mRNA can lead to the production of multiple
distinct protein isoforms is known as:
A) Alternative splicing
B) RNA editing
C) Polyadenylation
, D) Trans-translation
Answer: A
6. Which translation factor is responsible for delivering the aminoacyl-tRNA to the A-site
of the ribosome during elongation in eukaryotes?
A) eIF2
B) eEF1A
C) eEF2
D) eIF4E
Answer: B
7. MicroRNAs (miRNAs) inhibit gene expression primarily by which mechanism?
A) Inducing DNA methylation at the promoter
B) Binding to the 3' UTR to block translation or trigger mRNA degradation
C) Preventing transcription factor binding
D) Altering the ribosomal RNA structure
Answer: B
8. Which bacterial operon exhibits attenuation as a mechanism of transcriptional regulation
based on tryptophan levels?
A) lac operon
B) trp operon
C) ara operon
D) gal operon
Answer: B
9. In the lac operon, what occurs when both glucose and lactose are present in high
amounts?
A) Transcription is highly active.
B) The repressor is bound; transcription is blocked.
C) CAP-cAMP levels are low; transcription occurs at a basal level.
D) Attenuation halts transcription early.
Answer: C
10. What is the role of the sigma factor (σ) in prokaryotic transcription?
A) Elongation catalytic activity
B) Promoter recognition specificity
C) Termination sequence binding
D) RNA proofreading
Answer: B
11. Which RNA polymerase is responsible for synthesizing transfer RNA (tRNA) in
eukaryotic cells?
A) RNA Polymerase I
B) RNA Polymerase II
C) RNA Polymerase III
D) RNA Polymerase IV
Answer: C
12. The 7-methylguanosine cap is added to which end of the eukaryotic nascent mRNA?
A) 3' end via a 3'-3' linkage
B) 5' end via a 5'-5' triphosphate linkage
C) 3' end via a 5'-3' phosphodiester bond
, D) Internal adenine residues
Answer: B
13. What sequences define the boundaries of introns during pre-mRNA splicing?
A) 5'-AT and 3'-CG
B) 5'-GU and 3'-AG
C) 5'-AG and 3'-GU
D) 5'-AA and 3'-UU
Answer: B
14. Which complex is responsible for degrading polyadenylated mRNAs starting from the 3'
end?
A) Exosome complex
B) Proteasome
C) Spliceosome
D) Dicer
Answer: A
15. Rho-dependent transcription termination in bacteria relies on:
A) A stable hairpin loop followed by a string of U residues
B) The movement of Rho factor tracking along the RNA to destabilize the RNA-DNA
hybrid
C) The binding of a repressor protein to the operator
D) Direct cleavage by restriction endonucleases
Answer: B
16. Which enzyme catalyzes the attachment of amino acids to their corresponding tRNA
molecules?
A) RNA Polymerase
B) Peptidyl transferase
C) Aminoacyl-tRNA synthetase
D) Ribozyme
Answer: C
17. The Shine-Dalgarno sequence in prokaryotes is essential for:
A) Transcriptional termination
B) Correct positioning of the ribosome at the translation initiation site
C) mRNA stability against nucleases
D) Splicing node selection
Answer: B
18. What is the molecular target of the antibiotic Rifampicin?
A) Bacterial DNA Gyrase
B) Bacterial RNA Polymerase
C) 30S Ribosomal subunit
D) 50S Ribosomal subunit
Answer: B
19. Long non-coding RNAs (lncRNAs) can act as molecular "sponges" by binding and
neutralizing:
A) Ribosomes
B) MicroRNAs (miRNAs)
C) Histone deacetylases
(TWU) QUESTIONS AND
CORRECT ANSWERS)
180 multiple-choice and review questions spanning core advanced biological concepts,
accompanied by the correct answer key.
Part 1: Exam Guide Questions
Section 1: Advanced Molecular Biology & Gene Regulation (Questions 1–35)
1. Which of the following structural motifs is most commonly associated with sequence-
specific DNA binding by eukaryotic transcription factors?
A) Beta-barrel
B) Zinc finger
C) Alpha-sheet
D) Pleated domain
Answer: B
2. During DNA replication, which enzyme is responsible for relieving the torsional strain
ahead of the replication fork?
A) DNA Helicase
B) DNA Ligase
C) Topoisomerase
D) Primase
Answer: C
3. What is the primary function of the TATA-binding protein (TBP)?
A) To terminate transcription
B) To recruit RNA Polymerase II to the promoter
C) To facilitate tRNA charging
D) To catalyze mRNA splicing
Answer: B
4. Which modification to histone tails is most tightly coupled with active gene
transcription?
A) Methylation of H3K9
B) Acetylation of Lysine residues
C) Ubiquitination of H2A
D) Phosphorylation of Serine 10 only
Answer: B
5. The phenomenon where a single pre-mRNA can lead to the production of multiple
distinct protein isoforms is known as:
A) Alternative splicing
B) RNA editing
C) Polyadenylation
, D) Trans-translation
Answer: A
6. Which translation factor is responsible for delivering the aminoacyl-tRNA to the A-site
of the ribosome during elongation in eukaryotes?
A) eIF2
B) eEF1A
C) eEF2
D) eIF4E
Answer: B
7. MicroRNAs (miRNAs) inhibit gene expression primarily by which mechanism?
A) Inducing DNA methylation at the promoter
B) Binding to the 3' UTR to block translation or trigger mRNA degradation
C) Preventing transcription factor binding
D) Altering the ribosomal RNA structure
Answer: B
8. Which bacterial operon exhibits attenuation as a mechanism of transcriptional regulation
based on tryptophan levels?
A) lac operon
B) trp operon
C) ara operon
D) gal operon
Answer: B
9. In the lac operon, what occurs when both glucose and lactose are present in high
amounts?
A) Transcription is highly active.
B) The repressor is bound; transcription is blocked.
C) CAP-cAMP levels are low; transcription occurs at a basal level.
D) Attenuation halts transcription early.
Answer: C
10. What is the role of the sigma factor (σ) in prokaryotic transcription?
A) Elongation catalytic activity
B) Promoter recognition specificity
C) Termination sequence binding
D) RNA proofreading
Answer: B
11. Which RNA polymerase is responsible for synthesizing transfer RNA (tRNA) in
eukaryotic cells?
A) RNA Polymerase I
B) RNA Polymerase II
C) RNA Polymerase III
D) RNA Polymerase IV
Answer: C
12. The 7-methylguanosine cap is added to which end of the eukaryotic nascent mRNA?
A) 3' end via a 3'-3' linkage
B) 5' end via a 5'-5' triphosphate linkage
C) 3' end via a 5'-3' phosphodiester bond
, D) Internal adenine residues
Answer: B
13. What sequences define the boundaries of introns during pre-mRNA splicing?
A) 5'-AT and 3'-CG
B) 5'-GU and 3'-AG
C) 5'-AG and 3'-GU
D) 5'-AA and 3'-UU
Answer: B
14. Which complex is responsible for degrading polyadenylated mRNAs starting from the 3'
end?
A) Exosome complex
B) Proteasome
C) Spliceosome
D) Dicer
Answer: A
15. Rho-dependent transcription termination in bacteria relies on:
A) A stable hairpin loop followed by a string of U residues
B) The movement of Rho factor tracking along the RNA to destabilize the RNA-DNA
hybrid
C) The binding of a repressor protein to the operator
D) Direct cleavage by restriction endonucleases
Answer: B
16. Which enzyme catalyzes the attachment of amino acids to their corresponding tRNA
molecules?
A) RNA Polymerase
B) Peptidyl transferase
C) Aminoacyl-tRNA synthetase
D) Ribozyme
Answer: C
17. The Shine-Dalgarno sequence in prokaryotes is essential for:
A) Transcriptional termination
B) Correct positioning of the ribosome at the translation initiation site
C) mRNA stability against nucleases
D) Splicing node selection
Answer: B
18. What is the molecular target of the antibiotic Rifampicin?
A) Bacterial DNA Gyrase
B) Bacterial RNA Polymerase
C) 30S Ribosomal subunit
D) 50S Ribosomal subunit
Answer: B
19. Long non-coding RNAs (lncRNAs) can act as molecular "sponges" by binding and
neutralizing:
A) Ribosomes
B) MicroRNAs (miRNAs)
C) Histone deacetylases
