WGU Biochemistry Exam 1,2&3 COMBINATION examination 2025 -2026
QUESTIONS WITH CORRECT ANSWERS VERIFIED 100% GRADED A+
WGU Biochemistry
EXAM 1
Blood type is an example of what type of inheritance?
a. Codominance
The genes that produce the A and B antigen proteins can both be expressed
independently, and a heterozygote (someone with both genes) will be produce both
A and B proteins - neither will dominate the other. The is an example of
codominance.
What is the expected probability that a child will have an autosomal dominant
disease if their father is heterozygous for the allele and their mother is
homozygous for the normal allele?
a. 50%
If D is the disease-conferring dominant allele and d is the normal allele, the father
has the genotype Dd and the mother's genotype is dd. Each child can only inherit a d
allele from their mother, and they have a 50% chance of inheriting the D allele from
their father. As a result, the expected probability that their child will inherit the
disease is 50%.
The physical trait of lip protrusion exhibits a characteristic type of inheritance,
as shown by the pedigree above. What type of inheritance best describes this
inheritance pattern?
a. Incomplete dominance
The correct answer is incomplete dominance. The blending of the large and small lip
protrusion into an intermediate, medium lip protrusion, as well as the presence of all
three variations in the offspring, demonstrate a clear example of incomplete
dominance.
The normal sequence of a section of the HLA-B27 gene, a genetic marker of
the inflammatory disease Ankylosing spondylitis, is given below. Match each
mutation of the sequence to the type of mutation it exhibits. A genetic code
table is provided for your use in answering the question.
5'- CGG CAG AAU UUA -3'
5'- CAG CAG AAU UUA -3' - Missense mutation
5'- CGG CAG AAA UUU A-3' - Insertion
5'- CGG CAG AAC UUA -3' - Silent mutation
,5'- CGG CAG AAU UA -3' - Deletion
5'- CGG UAG AAU UUA-3' - Nonsense mutation
Silent mutations are those in which the amino acid encoded doesn't change as a
result of the mutation.
Missense mutations are those in which the amino acid encoded changes to a
different amino acid as a result of the mutation.
Nonsense mutations are those in which the amino acid encoded changes to a stop
codon as a result of the mutation, yielding a smaller protein.
Insertions are the inclusion of extra nucleotides compared to the original sequence.
They can result in other mutations, such as nonsense mutations.
Deletions are the removal of nucleotides compared to the original sequence. They
can result in other mutations, such as nonsense mutations.
PCR is a powerful tool that can do all of the following....
b. detect mutations that lead to disease
c. copy small segments of DNA, less than 6kb
d. amplify DNA from samples that have just a few cells
PCR's ability to amplify is powerful, and products can even be generated from
samples with just a few cells. PCR is less reliable for amplifying large segments of
DNA greater than 6 kb, though some careful changes to the techniques can allow it.
Which of the following is a required "ingredient" in a PCR
reaction?
a. DNA nucleotides
b. DNA primers
c. DNA polymerase
The primers used in PCR are made from DNA, rather than RNA. RNA primers are
used in DNA replication inside the cell, but the quick degradation of RNA makes it
less useful for PCR reactions. Instead, PCR reactions contain primers made of DNA
to anneal to the region of DNA that will be amplified and serve as a starting point for
DNA polymerase.
Which of the following changes can be detected using PCR?
a. Differences in DNA sequence
b. Insertions
c. Deletions
Differences in DNA sequence can be detected since these changes can alter the
ability of primers to anneal to the DNA. They can also be detected by DNA
sequencing of the PCR product. Epigenetic changes are not detectable via PCR
because they don't affect the DNA sequence.
,A small segment of Kevin's green opsin gene is shown below. What would be
the resulting mRNA sequence?
Kevin's opsin gene at nucleotide positions 936 to 941.
5'-G.C.C.T.A.G-3' (coding strand)
3'-C.G.G.A.T.C-5' (template strand)
c. 5'-GCCUAG-3'
This sequence is the same as the coding sequence, and the "T" bases have been
replaced with "U", as is found in RNA.
The gene for blue opsin protein is located on chromosome 7, a non-sex
chromosome. What kind of inheritance pattern would you expect to see with
color blindness due to a mutated blue opsin?
a. An equal distribution of blue color blindness between males and females.
The blue opsin gene is located on a somatic (non-sex) chromosome, and therefore
will be inherited with the same frequency for both sexes.
In Kevin's case, a specific kind of mutation in the opsin gene resulted in the
premature termination of the translation process. This resulted in a shorter
opsin protein than usual. What specific mutation could have caused this?
c. Nonsense mutations
Missense mutations are point mutations that change a single base pair in a codon
such that the codon now encodes a different amino acid. In Kevin's case, a
nonsense mutation, which is a point mutation that changes a single base pair in a
codon to a stop codon resulted in termination of the translation signal. This further
led to the synthesis of truncated protein.
After consultation with a genetic counselor and an examination of extended
family history, the following pedigree was generated. Who did Kevin most
likely inherit this mutation from?
a. Maternal grandfather
Red-green color blindness occurs more frequently in males than females because
these genes are located on the X chromosome, and males inherit only one X
chromosome and will express whatever alleles are on that chromosome. Females,
on the other hand, inherit two X chromosomes, and thus have two alleles for each
gene. If one of the alleles is mutated on one X chromosome, there is usually a
correct allele on the other that can provide the needed gene. A woman must have
two mutated opsin alleles to be color blind, while men need only one. This is known
as sex-linked inheritance. Kevin inherited his Y chromosome from his father and his
X chromosome from his mother, so his X chromosome with the defective opsin gene
most likely came from his maternal grandfather and was passed to him by his
, mother. Thus, both grandfathers is not correct because his paternal grandfather
would have contributed a Y chromosome.
The nonsense mutation that causes Kevin's color blindness could have
resulted from a malfunction of __________.
b. DNA polymerase
Helicase unwinds the DNA during replication, but doesn't add or remove nucleotides.
The correct choice is the DNA polymerase. DNA polymerase could have added an
erroneous nucleotide, and it's proofreading activity could have missed it. While this
type of event is rare, DNA polymerase is known to make a mistake that it doesn't
correct about one in one hundred million!
Primary structure consists of the order of ______ in a protein. These are held
together with ______ bonds that are formed by a ______ reaction.
a. Amino acids, peptide, dehydration
Correct Correct!
Several types of side chain interactions stabilize the tertiary structure of
proteins, including which of the following?
c. Ion pairs, hydrophobic interactions, hydrogen bonds, disulfide bonds
The stability of a tertiary structure of a protein depends on the various interactions
and bonds that occur between the side chains of different amino acids.
Which of the following statements is true about the secondary structure of
proteins?
a. It includes alpha helices as a common form.
c. It includes beta pleated sheets as a common form.
d. It involves hydrogen bonding between the backbone atoms.
A secondary structure of protein consists of hydrogen bonds between backbone
atoms, includes alpha helices and beta sheets as common forms.
In order to fulfill their function, proteins must fold in proper, three-dimensional
conformations. Which one of the following molecules, available in a cell, is
likely to help a protein fold properly?
b. Chaperone
Chaperones are helper proteins that ensure proper protein folding by stabilizing the
polypeptide until the correct structure is fully formed.
Which of the following is true about a misfolded protein?
a. It can be degraded by the cell.
b. It can cause protein aggregation.
d. It can be the result of denaturation.
e. It will lose its normal function.
QUESTIONS WITH CORRECT ANSWERS VERIFIED 100% GRADED A+
WGU Biochemistry
EXAM 1
Blood type is an example of what type of inheritance?
a. Codominance
The genes that produce the A and B antigen proteins can both be expressed
independently, and a heterozygote (someone with both genes) will be produce both
A and B proteins - neither will dominate the other. The is an example of
codominance.
What is the expected probability that a child will have an autosomal dominant
disease if their father is heterozygous for the allele and their mother is
homozygous for the normal allele?
a. 50%
If D is the disease-conferring dominant allele and d is the normal allele, the father
has the genotype Dd and the mother's genotype is dd. Each child can only inherit a d
allele from their mother, and they have a 50% chance of inheriting the D allele from
their father. As a result, the expected probability that their child will inherit the
disease is 50%.
The physical trait of lip protrusion exhibits a characteristic type of inheritance,
as shown by the pedigree above. What type of inheritance best describes this
inheritance pattern?
a. Incomplete dominance
The correct answer is incomplete dominance. The blending of the large and small lip
protrusion into an intermediate, medium lip protrusion, as well as the presence of all
three variations in the offspring, demonstrate a clear example of incomplete
dominance.
The normal sequence of a section of the HLA-B27 gene, a genetic marker of
the inflammatory disease Ankylosing spondylitis, is given below. Match each
mutation of the sequence to the type of mutation it exhibits. A genetic code
table is provided for your use in answering the question.
5'- CGG CAG AAU UUA -3'
5'- CAG CAG AAU UUA -3' - Missense mutation
5'- CGG CAG AAA UUU A-3' - Insertion
5'- CGG CAG AAC UUA -3' - Silent mutation
,5'- CGG CAG AAU UA -3' - Deletion
5'- CGG UAG AAU UUA-3' - Nonsense mutation
Silent mutations are those in which the amino acid encoded doesn't change as a
result of the mutation.
Missense mutations are those in which the amino acid encoded changes to a
different amino acid as a result of the mutation.
Nonsense mutations are those in which the amino acid encoded changes to a stop
codon as a result of the mutation, yielding a smaller protein.
Insertions are the inclusion of extra nucleotides compared to the original sequence.
They can result in other mutations, such as nonsense mutations.
Deletions are the removal of nucleotides compared to the original sequence. They
can result in other mutations, such as nonsense mutations.
PCR is a powerful tool that can do all of the following....
b. detect mutations that lead to disease
c. copy small segments of DNA, less than 6kb
d. amplify DNA from samples that have just a few cells
PCR's ability to amplify is powerful, and products can even be generated from
samples with just a few cells. PCR is less reliable for amplifying large segments of
DNA greater than 6 kb, though some careful changes to the techniques can allow it.
Which of the following is a required "ingredient" in a PCR
reaction?
a. DNA nucleotides
b. DNA primers
c. DNA polymerase
The primers used in PCR are made from DNA, rather than RNA. RNA primers are
used in DNA replication inside the cell, but the quick degradation of RNA makes it
less useful for PCR reactions. Instead, PCR reactions contain primers made of DNA
to anneal to the region of DNA that will be amplified and serve as a starting point for
DNA polymerase.
Which of the following changes can be detected using PCR?
a. Differences in DNA sequence
b. Insertions
c. Deletions
Differences in DNA sequence can be detected since these changes can alter the
ability of primers to anneal to the DNA. They can also be detected by DNA
sequencing of the PCR product. Epigenetic changes are not detectable via PCR
because they don't affect the DNA sequence.
,A small segment of Kevin's green opsin gene is shown below. What would be
the resulting mRNA sequence?
Kevin's opsin gene at nucleotide positions 936 to 941.
5'-G.C.C.T.A.G-3' (coding strand)
3'-C.G.G.A.T.C-5' (template strand)
c. 5'-GCCUAG-3'
This sequence is the same as the coding sequence, and the "T" bases have been
replaced with "U", as is found in RNA.
The gene for blue opsin protein is located on chromosome 7, a non-sex
chromosome. What kind of inheritance pattern would you expect to see with
color blindness due to a mutated blue opsin?
a. An equal distribution of blue color blindness between males and females.
The blue opsin gene is located on a somatic (non-sex) chromosome, and therefore
will be inherited with the same frequency for both sexes.
In Kevin's case, a specific kind of mutation in the opsin gene resulted in the
premature termination of the translation process. This resulted in a shorter
opsin protein than usual. What specific mutation could have caused this?
c. Nonsense mutations
Missense mutations are point mutations that change a single base pair in a codon
such that the codon now encodes a different amino acid. In Kevin's case, a
nonsense mutation, which is a point mutation that changes a single base pair in a
codon to a stop codon resulted in termination of the translation signal. This further
led to the synthesis of truncated protein.
After consultation with a genetic counselor and an examination of extended
family history, the following pedigree was generated. Who did Kevin most
likely inherit this mutation from?
a. Maternal grandfather
Red-green color blindness occurs more frequently in males than females because
these genes are located on the X chromosome, and males inherit only one X
chromosome and will express whatever alleles are on that chromosome. Females,
on the other hand, inherit two X chromosomes, and thus have two alleles for each
gene. If one of the alleles is mutated on one X chromosome, there is usually a
correct allele on the other that can provide the needed gene. A woman must have
two mutated opsin alleles to be color blind, while men need only one. This is known
as sex-linked inheritance. Kevin inherited his Y chromosome from his father and his
X chromosome from his mother, so his X chromosome with the defective opsin gene
most likely came from his maternal grandfather and was passed to him by his
, mother. Thus, both grandfathers is not correct because his paternal grandfather
would have contributed a Y chromosome.
The nonsense mutation that causes Kevin's color blindness could have
resulted from a malfunction of __________.
b. DNA polymerase
Helicase unwinds the DNA during replication, but doesn't add or remove nucleotides.
The correct choice is the DNA polymerase. DNA polymerase could have added an
erroneous nucleotide, and it's proofreading activity could have missed it. While this
type of event is rare, DNA polymerase is known to make a mistake that it doesn't
correct about one in one hundred million!
Primary structure consists of the order of ______ in a protein. These are held
together with ______ bonds that are formed by a ______ reaction.
a. Amino acids, peptide, dehydration
Correct Correct!
Several types of side chain interactions stabilize the tertiary structure of
proteins, including which of the following?
c. Ion pairs, hydrophobic interactions, hydrogen bonds, disulfide bonds
The stability of a tertiary structure of a protein depends on the various interactions
and bonds that occur between the side chains of different amino acids.
Which of the following statements is true about the secondary structure of
proteins?
a. It includes alpha helices as a common form.
c. It includes beta pleated sheets as a common form.
d. It involves hydrogen bonding between the backbone atoms.
A secondary structure of protein consists of hydrogen bonds between backbone
atoms, includes alpha helices and beta sheets as common forms.
In order to fulfill their function, proteins must fold in proper, three-dimensional
conformations. Which one of the following molecules, available in a cell, is
likely to help a protein fold properly?
b. Chaperone
Chaperones are helper proteins that ensure proper protein folding by stabilizing the
polypeptide until the correct structure is fully formed.
Which of the following is true about a misfolded protein?
a. It can be degraded by the cell.
b. It can cause protein aggregation.
d. It can be the result of denaturation.
e. It will lose its normal function.
