WGU Biochemistry EXAM QUESTION AND
ANSWERS|UPDATED VERSION|2025/2026
DNA polymerase is used in DNA replication and in PCR.
True
False ✔✔True
Feedback
Both PCR and DNA replication require DNA polymerase to make new copies of DNA.
Which of the following changes can NOT be detected using PCR?
Differences in DNA sequence
Epigenetic changes
Deletions
Insertions ✔✔Epigenetic changes
Feedback
Epigenetic changes do not affect the sequence of the DNA. PCR is used to look at the DNA
sequence.
Which of the following components is NOT used in PCR?
,DNA template
DNA nucleotides
RNA polymerase
Primers ✔✔RNA polymerase
Feedback
PCR makes a DNA copy, so DNA polymerase is used.
Assuming there is one copy of the target DNA sequence before PCR, how many copies of DNA
are there after 5 PCR cycles?
256
6
65,536
16
32 ✔✔32
Feedback
Each cycles double the numbers of DNA copy. Round 1: 1->2. Round 2: 2 ->4. Round 3: 4 -> 8.
Round 4: 8 ->16. Round 5: 16 ->32.
DNA polymerase can synthesize new DNA strands in which direction?
,3' to 5'
5' to 3' any
direction
N-terminus to C-terminus ✔✔5' to 3'
Feedback
DNA needs a free 3' end to bind to and initiate synthesis of a DNA. It synthesizes in a 5' to 3'
direction.
The following are steps involved in a polymerase chain reaction. Which is the correct order:
Elongation, denaturation, and annealing
Denaturation, annealing, and elongation
Annealing, elongation, and denaturation
Elongation, annealing, and denaturation ✔✔Denaturation, annealing, and elongation
Feedback
PCR uses repeated cycles of temperature to amplify particular DNA segments. In the first step,
the reaction mixture is heated to separate the DNA strands (denaturation). The reaction is then
cooled to allow the DNA primers, which define the sequence to be amplified, to anneal (base
pair) with the template DNA. In the third step, DNA polymerase extends the DNA primers to
, create a copy of the target DNA sequence. Heating the reaction to stop polymerization and
separate the DNA strands starts the cycle over again
Sickle Cell Anemia is inherited in an autosomal recessive pattern. Choose the set of
chromosomes of a person that has inherited the disease. Green boxes represent normal alleles and
yellow boxes represent mutant alleles.
Captionless Image
A. Chromosome 12 (Blue) vs. Chromosome 11 (Red)
B. Chromosome X (Blue) vs. Chromosome Y (Red, Short)
C. Chromosome 11 (Blue) vs. Chromosome 11 (Red w/green stripe)
D. Chromosome 11 (Blue) vs. Chromosome 11 (Red w/yellow stripe) ✔✔D. Chromosome 11
(Blue) vs. Chromosome 11 (Red w/yellow stripe)
Feedback
This question depicts chromosomes and asks which pair represents an Autosomal Recessive
inheritance pattern. Each of the chromosomes are pictured carrying an allele from each parent,
which is depicted by a yellow or green box. The green box represents a normal or dominant
allele, while the yellow box represents a mutant or recessive allele.
An Autosomal trait will be carried on a numbered chromosome and both chromosomes should
have the same number. An X-linked trait will be carried on an X-chromosome. This allows us to
rule out answer choices A and B.
ANSWERS|UPDATED VERSION|2025/2026
DNA polymerase is used in DNA replication and in PCR.
True
False ✔✔True
Feedback
Both PCR and DNA replication require DNA polymerase to make new copies of DNA.
Which of the following changes can NOT be detected using PCR?
Differences in DNA sequence
Epigenetic changes
Deletions
Insertions ✔✔Epigenetic changes
Feedback
Epigenetic changes do not affect the sequence of the DNA. PCR is used to look at the DNA
sequence.
Which of the following components is NOT used in PCR?
,DNA template
DNA nucleotides
RNA polymerase
Primers ✔✔RNA polymerase
Feedback
PCR makes a DNA copy, so DNA polymerase is used.
Assuming there is one copy of the target DNA sequence before PCR, how many copies of DNA
are there after 5 PCR cycles?
256
6
65,536
16
32 ✔✔32
Feedback
Each cycles double the numbers of DNA copy. Round 1: 1->2. Round 2: 2 ->4. Round 3: 4 -> 8.
Round 4: 8 ->16. Round 5: 16 ->32.
DNA polymerase can synthesize new DNA strands in which direction?
,3' to 5'
5' to 3' any
direction
N-terminus to C-terminus ✔✔5' to 3'
Feedback
DNA needs a free 3' end to bind to and initiate synthesis of a DNA. It synthesizes in a 5' to 3'
direction.
The following are steps involved in a polymerase chain reaction. Which is the correct order:
Elongation, denaturation, and annealing
Denaturation, annealing, and elongation
Annealing, elongation, and denaturation
Elongation, annealing, and denaturation ✔✔Denaturation, annealing, and elongation
Feedback
PCR uses repeated cycles of temperature to amplify particular DNA segments. In the first step,
the reaction mixture is heated to separate the DNA strands (denaturation). The reaction is then
cooled to allow the DNA primers, which define the sequence to be amplified, to anneal (base
pair) with the template DNA. In the third step, DNA polymerase extends the DNA primers to
, create a copy of the target DNA sequence. Heating the reaction to stop polymerization and
separate the DNA strands starts the cycle over again
Sickle Cell Anemia is inherited in an autosomal recessive pattern. Choose the set of
chromosomes of a person that has inherited the disease. Green boxes represent normal alleles and
yellow boxes represent mutant alleles.
Captionless Image
A. Chromosome 12 (Blue) vs. Chromosome 11 (Red)
B. Chromosome X (Blue) vs. Chromosome Y (Red, Short)
C. Chromosome 11 (Blue) vs. Chromosome 11 (Red w/green stripe)
D. Chromosome 11 (Blue) vs. Chromosome 11 (Red w/yellow stripe) ✔✔D. Chromosome 11
(Blue) vs. Chromosome 11 (Red w/yellow stripe)
Feedback
This question depicts chromosomes and asks which pair represents an Autosomal Recessive
inheritance pattern. Each of the chromosomes are pictured carrying an allele from each parent,
which is depicted by a yellow or green box. The green box represents a normal or dominant
allele, while the yellow box represents a mutant or recessive allele.
An Autosomal trait will be carried on a numbered chromosome and both chromosomes should
have the same number. An X-linked trait will be carried on an X-chromosome. This allows us to
rule out answer choices A and B.
