BIOD 101 MODULE 7 EXAM – GENETICS
AND MOLECULAR BIOLOGY
QUESTIONS & VERIFIED ANSWERS (A+
GUARANTEE)
1. Which enzyme is responsible for unwinding the DNA double helix by breaking hydrogen
bonds during DNA replication?
A. DNA Polymerase III
B. DNA Ligase
C. Topoisomerase
D. Helicase
Answer: D
Conceptual Explanation: Helicase is the enzyme that ‘unzips’ the DNA double helix by
breaking the hydrogen bonds between complementary base pairs.
2. In DNA replication, the leading strand is synthesized continuously, while the lagging strand
is synthesized in short pieces called:
A. Replicons
B. Primers
C. Introns
,D. Okazaki fragments
Answer: D
Conceptual Explanation: Okazaki fragments are the short, discontinuous segments of
DNA synthesized on the lagging strand due to the 5’ to 3’ directionality of DNA polymerase.
3. According to Chargaff’s rules, if a DNA sample contains 20% Adenine, what is the
percentage of Guanine?
A. 20%
B. 80%
C. 40%
D. 30%
Answer: D
Conceptual Explanation: If A=20%, then T=20% (Total 40%). The remaining 60% must
be split equally between G and C, so G=30%.
4. Which of the following nitrogenous bases is a purine?
A. Cytosine
B. Thymine
C. Guanine
D. Uracil
, Answer: C
Conceptual Explanation: Purines (Adenine and Guanine) have a double-ring structure,
while pyrimidines (Cytosine, Thymine, Uracil) have a single-ring structure.
5. What is the primary function of DNA Polymerase I in prokaryotic DNA replication?
A. Synthesizing the majority of new DNA
B. Attaching Okazaki fragments together
C. Relieving torsional strain ahead of the replication fork
D. Removing RNA primers and replacing them with DNA
Answer: D
Conceptual Explanation: DNA Polymerase I has 5’ to 3’ exonuclease activity, allowing it to
remove RNA primers and fill the gaps with DNA nucleotides.
6. Which process involves the synthesis of an RNA molecule from a DNA template?
A. Translation
B. Transcription
C. Transformation
D. Transduction
Answer: B
AND MOLECULAR BIOLOGY
QUESTIONS & VERIFIED ANSWERS (A+
GUARANTEE)
1. Which enzyme is responsible for unwinding the DNA double helix by breaking hydrogen
bonds during DNA replication?
A. DNA Polymerase III
B. DNA Ligase
C. Topoisomerase
D. Helicase
Answer: D
Conceptual Explanation: Helicase is the enzyme that ‘unzips’ the DNA double helix by
breaking the hydrogen bonds between complementary base pairs.
2. In DNA replication, the leading strand is synthesized continuously, while the lagging strand
is synthesized in short pieces called:
A. Replicons
B. Primers
C. Introns
,D. Okazaki fragments
Answer: D
Conceptual Explanation: Okazaki fragments are the short, discontinuous segments of
DNA synthesized on the lagging strand due to the 5’ to 3’ directionality of DNA polymerase.
3. According to Chargaff’s rules, if a DNA sample contains 20% Adenine, what is the
percentage of Guanine?
A. 20%
B. 80%
C. 40%
D. 30%
Answer: D
Conceptual Explanation: If A=20%, then T=20% (Total 40%). The remaining 60% must
be split equally between G and C, so G=30%.
4. Which of the following nitrogenous bases is a purine?
A. Cytosine
B. Thymine
C. Guanine
D. Uracil
, Answer: C
Conceptual Explanation: Purines (Adenine and Guanine) have a double-ring structure,
while pyrimidines (Cytosine, Thymine, Uracil) have a single-ring structure.
5. What is the primary function of DNA Polymerase I in prokaryotic DNA replication?
A. Synthesizing the majority of new DNA
B. Attaching Okazaki fragments together
C. Relieving torsional strain ahead of the replication fork
D. Removing RNA primers and replacing them with DNA
Answer: D
Conceptual Explanation: DNA Polymerase I has 5’ to 3’ exonuclease activity, allowing it to
remove RNA primers and fill the gaps with DNA nucleotides.
6. Which process involves the synthesis of an RNA molecule from a DNA template?
A. Translation
B. Transcription
C. Transformation
D. Transduction
Answer: B
