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# BIOCHEM C785 OA #2 READINESS CHECK
TEST BANK: 150+ EXAM-STYLE QUESTIONS
WITH VERIFIED ANSWERS & DETAILED
RATIONALES – FIRST-TIME PASS
## Table of Contents
| Domain | Topic Area | Question Numbers |
|--------|-----------|-------------------|
| Domain 1 | DNA Structure & Replication | 1-15 |
| Domain 2 | Transcription & Translation (Central Dogma) | 16-35 |
| Domain 3 | Mutations & DNA Repair Mechanisms | 36-50 |
| Domain 4 | Protein Structure & Folding | 51-70 |
| Domain 5 | Enzyme Function & Kinetics | 71-85 |
| Domain 6 | Metabolism & Energetics | 86-105 |
| Domain 7 | Genetic Inheritance Patterns | 106-120 |
| Domain 8 | Metabolic Disorders & Case Studies | 121-135 |
| Domain 9 | Laboratory Techniques (PCR, Gel Electrophoresis) | 136-
145 |
| Domain 10 | NGN-Style Integrated Scenarios | 146-150 |
,2|Page
# DOMAIN 1: DNA STRUCTURE & REPLICATION## Questions 1-15
**Q1.** What is the complementary sequence to 3' ATG CGA ATA 5'?
A) 3' TAT TCG CAT 5'
B) 3' TAC GCT TAT 5'
C) 3' GAT AGC ATA 5'
D) 5' ATA AGC GTA 3'
**Answer: A) 3' TAT TCG CAT 5'**
**Rationale:** Complementary base pairing rules (A-T, G-C) must be
applied while maintaining antiparallel orientation (5' to 3' pairing with 3'
to 5'). The original is 3' ATG CGA ATA 5', so complementary is 5' TAC
GCT TAT 3'. To express in 3'→5' direction (as requested), reverse to 3'
TAT TCG CAT 5'. This reflects the antiparallel nature of DNA.
**Q2.** During DNA replication, which enzyme is responsible for
synthesizing the new DNA strand by adding nucleotides to the 3' end?
A) DNA Ligase
B) DNA Polymerase
C) Helicase
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D) Primase
**Answer: B) DNA Polymerase**
**Rationale:** DNA Polymerase catalyzes the addition of
deoxyribonucleotides to the growing 3' hydroxyl end of a DNA strand,
synthesizing new DNA complementary to the template strand. Helicase
unwinds DNA, primase synthesizes RNA primers, and DNA ligase seals
nicks.
**Q3.** Which of the following are the correct components for a PCR
reaction?
A) dNTPs, Primer, RNA Polymerase, template RNA
B) dNTPs, Primer, DNA Polymerase, template DNA
C) ATP, Primer, mRNA Polymerase, template mRNA
D) Acetyl CoA, RNA primer, DNA Ligase, Template phosphate
**Answer: B) dNTPs, Primer, DNA Polymerase, template DNA**
**Rationale:** PCR requires deoxynucleotide triphosphates (dNTPs) as
building blocks, primers to initiate synthesis, a heat-stable DNA
polymerase (e.g., Taq polymerase), and template DNA. RNA
polymerase is used in transcription, not PCR.
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**Q4.** What is the role of helicase in DNA replication?
A) Relieves supercoiling ahead of the replication fork
B) Joins Okazaki fragments on the lagging strand
C) Unwinds the double helix by breaking hydrogen bonds between base
pairs
D) Synthesizes RNA primers to initiate DNA synthesis
**Answer: C) Unwinds the double helix by breaking hydrogen bonds
between base pairs**
**Rationale:** Helicase is the enzyme responsible for unwinding the
DNA double helix by breaking hydrogen bonds between complementary
base pairs, creating two single-stranded templates for replication.
**Q5.** Which statement correctly describes the directionality of DNA
synthesis?
A) DNA is synthesized in the 3'→5' direction on both strands
B) DNA is synthesized in the 5'→3' direction on the leading strand and
3'→5' on the lagging strand
C) DNA is synthesized in the 5'→3' direction on both strands
D) DNA synthesis direction depends on the type of polymerase used
# BIOCHEM C785 OA #2 READINESS CHECK
TEST BANK: 150+ EXAM-STYLE QUESTIONS
WITH VERIFIED ANSWERS & DETAILED
RATIONALES – FIRST-TIME PASS
## Table of Contents
| Domain | Topic Area | Question Numbers |
|--------|-----------|-------------------|
| Domain 1 | DNA Structure & Replication | 1-15 |
| Domain 2 | Transcription & Translation (Central Dogma) | 16-35 |
| Domain 3 | Mutations & DNA Repair Mechanisms | 36-50 |
| Domain 4 | Protein Structure & Folding | 51-70 |
| Domain 5 | Enzyme Function & Kinetics | 71-85 |
| Domain 6 | Metabolism & Energetics | 86-105 |
| Domain 7 | Genetic Inheritance Patterns | 106-120 |
| Domain 8 | Metabolic Disorders & Case Studies | 121-135 |
| Domain 9 | Laboratory Techniques (PCR, Gel Electrophoresis) | 136-
145 |
| Domain 10 | NGN-Style Integrated Scenarios | 146-150 |
,2|Page
# DOMAIN 1: DNA STRUCTURE & REPLICATION## Questions 1-15
**Q1.** What is the complementary sequence to 3' ATG CGA ATA 5'?
A) 3' TAT TCG CAT 5'
B) 3' TAC GCT TAT 5'
C) 3' GAT AGC ATA 5'
D) 5' ATA AGC GTA 3'
**Answer: A) 3' TAT TCG CAT 5'**
**Rationale:** Complementary base pairing rules (A-T, G-C) must be
applied while maintaining antiparallel orientation (5' to 3' pairing with 3'
to 5'). The original is 3' ATG CGA ATA 5', so complementary is 5' TAC
GCT TAT 3'. To express in 3'→5' direction (as requested), reverse to 3'
TAT TCG CAT 5'. This reflects the antiparallel nature of DNA.
**Q2.** During DNA replication, which enzyme is responsible for
synthesizing the new DNA strand by adding nucleotides to the 3' end?
A) DNA Ligase
B) DNA Polymerase
C) Helicase
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D) Primase
**Answer: B) DNA Polymerase**
**Rationale:** DNA Polymerase catalyzes the addition of
deoxyribonucleotides to the growing 3' hydroxyl end of a DNA strand,
synthesizing new DNA complementary to the template strand. Helicase
unwinds DNA, primase synthesizes RNA primers, and DNA ligase seals
nicks.
**Q3.** Which of the following are the correct components for a PCR
reaction?
A) dNTPs, Primer, RNA Polymerase, template RNA
B) dNTPs, Primer, DNA Polymerase, template DNA
C) ATP, Primer, mRNA Polymerase, template mRNA
D) Acetyl CoA, RNA primer, DNA Ligase, Template phosphate
**Answer: B) dNTPs, Primer, DNA Polymerase, template DNA**
**Rationale:** PCR requires deoxynucleotide triphosphates (dNTPs) as
building blocks, primers to initiate synthesis, a heat-stable DNA
polymerase (e.g., Taq polymerase), and template DNA. RNA
polymerase is used in transcription, not PCR.
, 4|Page
**Q4.** What is the role of helicase in DNA replication?
A) Relieves supercoiling ahead of the replication fork
B) Joins Okazaki fragments on the lagging strand
C) Unwinds the double helix by breaking hydrogen bonds between base
pairs
D) Synthesizes RNA primers to initiate DNA synthesis
**Answer: C) Unwinds the double helix by breaking hydrogen bonds
between base pairs**
**Rationale:** Helicase is the enzyme responsible for unwinding the
DNA double helix by breaking hydrogen bonds between complementary
base pairs, creating two single-stranded templates for replication.
**Q5.** Which statement correctly describes the directionality of DNA
synthesis?
A) DNA is synthesized in the 3'→5' direction on both strands
B) DNA is synthesized in the 5'→3' direction on the leading strand and
3'→5' on the lagging strand
C) DNA is synthesized in the 5'→3' direction on both strands
D) DNA synthesis direction depends on the type of polymerase used
