WGU Biochemistry with questions and
answers.
,
,DNA replication is ___________, which allows each of the two strands to serve
as a _______ for the new strands.
b. semiconservative, template - correct ans: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 - correct ans: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 - correct ans: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 - correct ans: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 - correct ans: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% - correct ans: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%.
answers.
,
,DNA replication is ___________, which allows each of the two strands to serve
as a _______ for the new strands.
b. semiconservative, template - correct ans: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 - correct ans: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 - correct ans: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 - correct ans: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 - correct ans: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% - correct ans: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%.
