WGU BIOCHEMISTRY OA EXAM 2026
COMPLETE QUESTIONS AND ANSWERS
GRADED A+
◉ What color is the primer in the following diagram?
Red
Purple
Blue. Answer: Red
Feedback
Recall from the section on DNA replication that DNA polymerase
needs a primer to begin DNA synthesis. This requirement means the
primers will direct the DNA polymerase to only synthesize
complementary strands of the target DNA. (Note: In DNA replication,
the primers are RNA primers, while PCR generally uses DNA primers
because they are more stable.)
◉ dNTPs are DNA nucleotides used in PCR.
True
False. Answer: True
,Feedback
dNTPs stands for deoxynucleotide triphosphates, which are the
nucleotides used in DNA synthesis.
◉ A thermocycler is a machine used for PCR that varies the
temperature of a sample.
True
False. Answer: True
Feedback
For PCR, in each cycle, the two strands of the duplex DNA are
separated by heating, then the reaction mixture is cooled to allow
the primers to anneal (or pair) to their complementary segments on
the DNA. Next, the DNA polymerase directs the synthesis of the
complementary strands. The use of a heat-stable DNA polymerase
eliminates the need to add fresh enzyme after each round of heating
(heat inactivates most enzymes). Hence, in the presence of sufficient
quantities of primers and dNTPs, PCR is carried out simply by
cycling through the different temperatures for strand separation,
primer annealing, and DNA synthesis.
The thermocycler is the machine that is used to vary the
temperature of the samples.
,◉ DNA polymerase is used in DNA replication and in PCR.
True
False. Answer: 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. Answer: 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. Answer: 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. Answer: 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.
COMPLETE QUESTIONS AND ANSWERS
GRADED A+
◉ What color is the primer in the following diagram?
Red
Purple
Blue. Answer: Red
Feedback
Recall from the section on DNA replication that DNA polymerase
needs a primer to begin DNA synthesis. This requirement means the
primers will direct the DNA polymerase to only synthesize
complementary strands of the target DNA. (Note: In DNA replication,
the primers are RNA primers, while PCR generally uses DNA primers
because they are more stable.)
◉ dNTPs are DNA nucleotides used in PCR.
True
False. Answer: True
,Feedback
dNTPs stands for deoxynucleotide triphosphates, which are the
nucleotides used in DNA synthesis.
◉ A thermocycler is a machine used for PCR that varies the
temperature of a sample.
True
False. Answer: True
Feedback
For PCR, in each cycle, the two strands of the duplex DNA are
separated by heating, then the reaction mixture is cooled to allow
the primers to anneal (or pair) to their complementary segments on
the DNA. Next, the DNA polymerase directs the synthesis of the
complementary strands. The use of a heat-stable DNA polymerase
eliminates the need to add fresh enzyme after each round of heating
(heat inactivates most enzymes). Hence, in the presence of sufficient
quantities of primers and dNTPs, PCR is carried out simply by
cycling through the different temperatures for strand separation,
primer annealing, and DNA synthesis.
The thermocycler is the machine that is used to vary the
temperature of the samples.
,◉ DNA polymerase is used in DNA replication and in PCR.
True
False. Answer: 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. Answer: 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. Answer: 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. Answer: 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.
