,BIOL 102 Module 1 | Essential Biology II w/Lab
Exam Q&A | Portage Learning
1. Which term describes the process by which a DNA molecule is copied to produce
two identical DNA molecules?
A) Transcription
B) Translation
C) Replication
D) Mutation
Correct Answer: Replication
Rationale: DNA replication is the process of copying a DNA molecule to produce
two identical daughter molecules. Transcription produces RNA from a DNA
template, translation synthesizes protein from mRNA, and mutation is a change in
the DNA sequence.
2. What is the primary function of DNA helicase during replication?
A) To synthesize new DNA strands
B) To unwind the DNA double helix
C) To join Okazaki fragments
D) To proofread newly synthesized DNA
Correct Answer: To unwind the DNA double helix
,Rationale: DNA helicase breaks the hydrogen bonds between complementary
base pairs, separating the two strands of the double helix to create replication
forks. DNA polymerase synthesizes new strands, ligase joins fragments, and
proofreading is a separate function.
3. Which enzyme synthesizes new DNA strands by adding nucleotides
complementary to the template strand?
A) DNA ligase
B) DNA polymerase
C) RNA primase
D) Helicase
Correct Answer: DNA polymerase
Rationale: DNA polymerase adds deoxynucleotide triphosphates to the growing
DNA strand in a template-directed manner. Ligase seals nicks, primase synthesizes
RNA primers, and helicase unwinds the double helix.
4. Why is DNA replication described as semiconservative?
A) Each new double helix contains one original and one new strand.
B) Both strands of the new double helix are newly synthesized.
C) The original DNA molecule remains completely intact.
D) Replication occurs only in one direction.
Correct Answer: Each new double helix contains one original and one new
strand.
, Rationale: Semiconservative replication means that each daughter DNA
molecule consists of one parental (original) strand and one newly synthesized
strand. This was demonstrated by the Meselson–Stahl experiment.
5. Which strand is synthesized continuously toward the replication fork during
DNA replication?
A) Leading strand
B) Lagging strand
C) Template strand
D) Coding strand
Correct Answer: Leading strand
Rationale: The leading strand is synthesized continuously in the same direction
as the replication fork movement. The lagging strand is synthesized
discontinuously in short Okazaki fragments away from the fork.
6. What are Okazaki fragments?
A) Short RNA primers
B) Short DNA segments synthesized discontinuously on the lagging strand
C) Proteins that unwind DNA
D) Enzymes that proofread DNA
Correct Answer: Short DNA segments synthesized discontinuously on the
lagging strand
Exam Q&A | Portage Learning
1. Which term describes the process by which a DNA molecule is copied to produce
two identical DNA molecules?
A) Transcription
B) Translation
C) Replication
D) Mutation
Correct Answer: Replication
Rationale: DNA replication is the process of copying a DNA molecule to produce
two identical daughter molecules. Transcription produces RNA from a DNA
template, translation synthesizes protein from mRNA, and mutation is a change in
the DNA sequence.
2. What is the primary function of DNA helicase during replication?
A) To synthesize new DNA strands
B) To unwind the DNA double helix
C) To join Okazaki fragments
D) To proofread newly synthesized DNA
Correct Answer: To unwind the DNA double helix
,Rationale: DNA helicase breaks the hydrogen bonds between complementary
base pairs, separating the two strands of the double helix to create replication
forks. DNA polymerase synthesizes new strands, ligase joins fragments, and
proofreading is a separate function.
3. Which enzyme synthesizes new DNA strands by adding nucleotides
complementary to the template strand?
A) DNA ligase
B) DNA polymerase
C) RNA primase
D) Helicase
Correct Answer: DNA polymerase
Rationale: DNA polymerase adds deoxynucleotide triphosphates to the growing
DNA strand in a template-directed manner. Ligase seals nicks, primase synthesizes
RNA primers, and helicase unwinds the double helix.
4. Why is DNA replication described as semiconservative?
A) Each new double helix contains one original and one new strand.
B) Both strands of the new double helix are newly synthesized.
C) The original DNA molecule remains completely intact.
D) Replication occurs only in one direction.
Correct Answer: Each new double helix contains one original and one new
strand.
, Rationale: Semiconservative replication means that each daughter DNA
molecule consists of one parental (original) strand and one newly synthesized
strand. This was demonstrated by the Meselson–Stahl experiment.
5. Which strand is synthesized continuously toward the replication fork during
DNA replication?
A) Leading strand
B) Lagging strand
C) Template strand
D) Coding strand
Correct Answer: Leading strand
Rationale: The leading strand is synthesized continuously in the same direction
as the replication fork movement. The lagging strand is synthesized
discontinuously in short Okazaki fragments away from the fork.
6. What are Okazaki fragments?
A) Short RNA primers
B) Short DNA segments synthesized discontinuously on the lagging strand
C) Proteins that unwind DNA
D) Enzymes that proofread DNA
Correct Answer: Short DNA segments synthesized discontinuously on the
lagging strand
