WGU Biochemistry Final Review 2022 questions and answers latest

WGU Biochemistry Final Review 2022

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

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) Correct Answer: D.
Chromosome 11 (Blue) vs. Chromosome 11 (Red w/yellow stripe)

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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.

To inherit a recessive trait, we need to inherit two recessive (or mutant alleles), which would be
shown as two yellow boxes. A dominant trait can be inherited when one or two dominant alleles are
present. Answer choice C depicts an Autosomal Dominant inheritance, while answer choice D is the
correct answer because it depicts an Autosomal Recessive inheritance pattern.

Hemophilia is an X-linked recessive condition. This means that:

1. A person with at least one normal X chromosome without the hemophilia gene will not show signs
of hemophilia
2. The disease is more common in females
3. Affected men can pass the condition on to sons but not to daughters
4. Women can only pass the condition on to daughters Correct Answer: 1. A person with at least one
normal X chromosome without the hemophilia gene will not show signs of hemophilia

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An X-linked recessive condition is inherited when a female has a recessive allele on each of her X
chromosomes. Males inherit an X-linked recessive condition if they inherit a recessive allele on their
one and only X chromosome. Therefore if a female has a dominant (or normal) allele on one of her X
chromosomes, she will not have the disease.
Because men only have one X-chromosome, they tend to inherit X-linked conditions more easily than
females.

Men with X-linked recessive conditions do not pass the disease on to their sons, because they pass a
Y chromosome on to their sons. Men will pass an X chromosome to their daughters.

Women are able to pass an X chromosome on to their son or their daughters.

A woman is homozygous for an abnormal allele on Chromosome 2 that codes for an autosomal
dominant disease. This means that she:

Will have the disease
Will not have the disease
Has one normal gene and one abnormal gene
Can pass on two genes to any daughters and one gene to any son Correct Answer: Will have the
disease

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Homozygous means that the woman will have two copies of the abnormal allele. An abnormal allele
is the allele that can lead to disease. Since the disease is dominant, then the abnormal allele is
dominant in this case. With two copies of a dominant allele, an individual will inherit a dominant
disease.

Mutations in the FANCA gene (located on chromosome 16) can lead to Fanconi Anemia. A healthy
individual inherited one mutant and one normal allele of the FANCA gene. Which of the following
describes the inheritance pattern of Fanconi Anemia?

Autosomal Dominant
Autosomal Recessive
X-linked Dominant
X-linked Recessive Correct Answer: Autosomal Recessive

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Chromosome 16 is an autosome because it is a numbered chromosome. For a healthy individual to
have a mutant allele, the mutant allele must be recessive.

A black female mouse mates with a white male mouse and produces a litter of all gray mice. Which
inheritance pattern can be used to describe this situation?

Complete Dominance
Recessive
Incomplete Dominance
Codominance Correct Answer: Incomplete Dominance