WGU BIOCHEMISTRY OA UPDATED FINAL EXAMS ACTUAL QUESTIONS AND ANSWERS SURE

WGU BIOCHEMISTRY OA UPDATED FINAL EXAMS
ACTUAL QUESTIONS AND ANSWERS SURE A+
✔✔Which of the following changes can NOT be detected using PCR?

Differences in DNA sequence
Epigenetic changes
Deletions
Insertions - ✔✔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 - ✔✔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 - ✔✔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 - ✔✔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 - ✔✔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) - ✔✔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 - ✔✔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 - ✔✔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 - ✔✔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 - ✔✔Incomplete Dominance

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Incomplete dominance produces a blended phenotype.