Wgu Biochemistry Exam need to Study Questions
and Answers Verifies 100% Correct
DNA replication is ___________, which allows each of the two strands to serve as a
_______ for the new strands.
b. semiconservative, template
DNA replication is semiconservative, meaning that each new duplex has one original
(parent) strand and one new strand. Because the two parent strands are separated
during replication and the base pairing is predictable, each parent strand can serve as a
template for the new strand synthesis.
Which of the following enzymes does NOT assist the DNA polymerase on the lagging
strand to overcome its two problems? (Recall that the DNA polymerase can only make
DNA in the 5'->3' direction, and it must bind a double-stranded nucleotide polymer
before it can start making its own DNA polymer.)
c. Helicase
Helicase unwinds the double stranded DNA to allow for replication, but this is not a
problem for the DNA polymerase.
Several components of cigarette smoke, including benzopyrene, insert themselves
(intercalate) into the DNA and lead to several types of mutations such as frameshift
mutations, including both insertions and deletion. Which of the following repair
pathways would be used to repair this type of damage?
c. Nucleotide Excision Repair
,Nucleotide excision repair is used to repair deletions, insertions, and helix-distorting
lesions, such as thymine dimers.
Maternal smoking during pregnancy is hazardous yet common in many places. Many
studies have associated prenatal smoking to unhealthy physical and psychological
outcomes for the baby. Researchers know that maternal smoking affects are
epigenetic in nature. Which of the following events can be considered epigenetic in
nature?
a. Changes in chromatin structure
Frame shift mutations are a kind of mutations which result from addition of deletion of
a nucleotide base resulting in an altered reading frame and ultimately a different
protein, than the one the gene originally encoded. Frameshift mutations are genetic
changes because they alter the DNA sequence, whereas epigenetic changes do not alter
the DNA sequence. Epigenetic changes are modifications to genomic structure (not
sequence) that are caused by the external environment. These environmental factors
affect the overall chromatin structure to allow more or less "access" to the DNA by gene
expression machinery to turn the genes "on" or "off". In other words, epigenetics can
alter gene expression without changing the underlying DNA sequences. The changes
may or may not be heritable, depending on the location and circumstances.
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
and Answers Verifies 100% Correct
DNA replication is ___________, which allows each of the two strands to serve as a
_______ for the new strands.
b. semiconservative, template
DNA replication is semiconservative, meaning that each new duplex has one original
(parent) strand and one new strand. Because the two parent strands are separated
during replication and the base pairing is predictable, each parent strand can serve as a
template for the new strand synthesis.
Which of the following enzymes does NOT assist the DNA polymerase on the lagging
strand to overcome its two problems? (Recall that the DNA polymerase can only make
DNA in the 5'->3' direction, and it must bind a double-stranded nucleotide polymer
before it can start making its own DNA polymer.)
c. Helicase
Helicase unwinds the double stranded DNA to allow for replication, but this is not a
problem for the DNA polymerase.
Several components of cigarette smoke, including benzopyrene, insert themselves
(intercalate) into the DNA and lead to several types of mutations such as frameshift
mutations, including both insertions and deletion. Which of the following repair
pathways would be used to repair this type of damage?
c. Nucleotide Excision Repair
,Nucleotide excision repair is used to repair deletions, insertions, and helix-distorting
lesions, such as thymine dimers.
Maternal smoking during pregnancy is hazardous yet common in many places. Many
studies have associated prenatal smoking to unhealthy physical and psychological
outcomes for the baby. Researchers know that maternal smoking affects are
epigenetic in nature. Which of the following events can be considered epigenetic in
nature?
a. Changes in chromatin structure
Frame shift mutations are a kind of mutations which result from addition of deletion of
a nucleotide base resulting in an altered reading frame and ultimately a different
protein, than the one the gene originally encoded. Frameshift mutations are genetic
changes because they alter the DNA sequence, whereas epigenetic changes do not alter
the DNA sequence. Epigenetic changes are modifications to genomic structure (not
sequence) that are caused by the external environment. These environmental factors
affect the overall chromatin structure to allow more or less "access" to the DNA by gene
expression machinery to turn the genes "on" or "off". In other words, epigenetics can
alter gene expression without changing the underlying DNA sequences. The changes
may or may not be heritable, depending on the location and circumstances.
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
