WGU Biochemistry Final Review UPDATED ACTUAL Exam Questions and CORRECT Answers

WGU Biochemistry Final Review UPDATED
ACTUAL Exam Questions and CORRECT
Answers
1. The polymerase chain reaction is a tool used to study protein structure.


True

False - CORRECT ANSWER - 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 - CORRECT ANSWER - 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 - CORRECT ANSWER - 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 - CORRECT ANSWER - 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 - CORRECT ANSWER - 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 - CORRECT ANSWER - 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 - CORRECT ANSWER - 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
6
65,536
16

32 - CORRECT ANSWER - 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 - CORRECT ANSWER - 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 - CORRECT ANSWER - Denaturation,
annealing, and elongation


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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