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BIOCHEM 423- UNIT 4 EXAM REVIEW 2026-
COMPLETE EXAM SET WITH ACTUAL QUESTIONS
AND VERIFIED SOLUTIONS
Arrange the steps of DNA replication in the order that they occur. - correct-answer
-1. Helicase unwinds the DNA double helix
2. Single-stranded DNA-binding proteins bind to each template strand
3. RNA primers are added
4. DNA polymerase synthesizes DNA
5. RNA primers are removed
6. DNA ligase joins DNA fragments together
DNA replication involves multiple steps that require different enzymes. Which
process does primase catalyze in DNA replication? - correct-answer -synthesis of a
short RNA sequence that initiates DNA synthesis
Match each protein to its role in DNA replication. - correct-answer -1. DNA
topoisomerase relaxes the supercoiled DNA.
2. Helicase unwinds the DNA double helix.
3. SSB proteins prevent the reannealing of DNA strands.
4. DNA polymerase III synthesizes new DNA.
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5. DNA Ligase connects the separated DNA segments.
As DNA is replicated, both continuous and discontinuous replication occur.
Discontinuous replication is the result of which specific feature of DNA? - correct-
answer -antiparallel strands
Identify each characteristic as belonging to the leading strand or the lagging
strand in DNA synthesis. - correct-answer -Leading strand: synthesized
continuously, movement of the replication fork in the 5' to 3' direction
Lagging strand: formed as Okazaki fragments, movement of the replication fork in
the 3' to 5' direction, forms loops during replication
Classify each statement as describing DNA replication in prokaryotes, eukaryotes,
both, or neither. - correct-answer -Eukaryotic replication: several origins of
replication, specific dna polymerase for mitochondrial dna replication
Both: several types of dna polymerases, bidirectional replication
Neither prokaryotic or eukaryotic replication occurs during the M phase of the cell
cycle
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Place the steps of eukaryotic DNA replication in order, from when a germ cell
enters gap 1 (G1) phase to the cell cycle termination. - correct-answer -Cell enters
Gap 1
1. each genomic origin of replication assembles a pre-replication complex
2. the initiation complex creates an active replication fork as helicase unwinds dna
3. rna primers are added to provide a 3' end for elongation
4. dna polymerase synthesizes both the leading and lagging strands from 5' to 3'
5. rna is replaced with dna and lagging strands are joined
6. active telomerase can extend the lost telomere region
Cell cycle termination
One of the biologically harmful effects of ultraviolet (UV) light is its action on DNA.
How does UV light alter DNA? - correct-answer -covalent formation of pyrimidine
dimers involving adjacent pyrimidines along a DNA strand
If a DNA molecule is damaged, it - correct-answer -is possible to repair the
damage in the site where it occurs
Which process is NOT a possible type of damage to DNA? - correct-answer -
formation of more than three hydrogen bonds in a Watson-Crick base pair
BIOCHEM 423- UNIT 4 EXAM REVIEW 2026-
COMPLETE EXAM SET WITH ACTUAL QUESTIONS
AND VERIFIED SOLUTIONS
Arrange the steps of DNA replication in the order that they occur. - correct-answer
-1. Helicase unwinds the DNA double helix
2. Single-stranded DNA-binding proteins bind to each template strand
3. RNA primers are added
4. DNA polymerase synthesizes DNA
5. RNA primers are removed
6. DNA ligase joins DNA fragments together
DNA replication involves multiple steps that require different enzymes. Which
process does primase catalyze in DNA replication? - correct-answer -synthesis of a
short RNA sequence that initiates DNA synthesis
Match each protein to its role in DNA replication. - correct-answer -1. DNA
topoisomerase relaxes the supercoiled DNA.
2. Helicase unwinds the DNA double helix.
3. SSB proteins prevent the reannealing of DNA strands.
4. DNA polymerase III synthesizes new DNA.
,2|Page
5. DNA Ligase connects the separated DNA segments.
As DNA is replicated, both continuous and discontinuous replication occur.
Discontinuous replication is the result of which specific feature of DNA? - correct-
answer -antiparallel strands
Identify each characteristic as belonging to the leading strand or the lagging
strand in DNA synthesis. - correct-answer -Leading strand: synthesized
continuously, movement of the replication fork in the 5' to 3' direction
Lagging strand: formed as Okazaki fragments, movement of the replication fork in
the 3' to 5' direction, forms loops during replication
Classify each statement as describing DNA replication in prokaryotes, eukaryotes,
both, or neither. - correct-answer -Eukaryotic replication: several origins of
replication, specific dna polymerase for mitochondrial dna replication
Both: several types of dna polymerases, bidirectional replication
Neither prokaryotic or eukaryotic replication occurs during the M phase of the cell
cycle
, 3|Page
Place the steps of eukaryotic DNA replication in order, from when a germ cell
enters gap 1 (G1) phase to the cell cycle termination. - correct-answer -Cell enters
Gap 1
1. each genomic origin of replication assembles a pre-replication complex
2. the initiation complex creates an active replication fork as helicase unwinds dna
3. rna primers are added to provide a 3' end for elongation
4. dna polymerase synthesizes both the leading and lagging strands from 5' to 3'
5. rna is replaced with dna and lagging strands are joined
6. active telomerase can extend the lost telomere region
Cell cycle termination
One of the biologically harmful effects of ultraviolet (UV) light is its action on DNA.
How does UV light alter DNA? - correct-answer -covalent formation of pyrimidine
dimers involving adjacent pyrimidines along a DNA strand
If a DNA molecule is damaged, it - correct-answer -is possible to repair the
damage in the site where it occurs
Which process is NOT a possible type of damage to DNA? - correct-answer -
formation of more than three hydrogen bonds in a Watson-Crick base pair
