WGU Biochemistry Final Review Questions and Answers

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WGU Biochemistry Final Review Questions
and Answers

1. The polymerase chain reaction is a tool used to study protein
structure.

True
False
Ans: False


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PCR is a tool used to amplify a specific segment of DNA.

What color is the primer in the following diagram?

Red
Purple
Blue
Ans: Red


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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
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Ans: True


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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
Ans: True


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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




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Ans: True


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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
Ans: Epigenetic changes


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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
Ans: RNA polymerase


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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

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6
65,536
16
32
Ans: 32


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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
Ans: 5' to 3'


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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




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