BIOC 385 Exam 4 questions n answers
graded A+ passed
after transcription initiation but early in elongation - correct answer ✔✔When is the 5′ m7G cap
added to an mRNA transcript?
Ligand binding can have positive and negative control over transcription. Binding of a ligand to a
repressor can either activate the repressor or inactivate the repressor, causing either inhibition
or activation, respectively. Ligand binding to an activator can also either activate or inactivate
the activator, which can turn on or turn off transcription, respectively. - correct answer ✔✔In
the figure below, which situation involves activation under positive control of ligand binding?
Eukaryotes encode a greater variety of ncRNA than prokaryotes. - correct answer ✔✔Which of
these is a difference in the total RNA content of prokaryotes and eukaryotes?
Gyrase - correct answer ✔✔Which replication fork enzyme relieves torsional stress in front of
the fork?
Uncharged tRNA recognition of stop codon in the mRNA - correct answer ✔✔Which of the
following is NOT a part of translational termination?
lncRNA can be translated to produce a ribonucleoprotein complex that binds to DNA and
recruits other protein complexes that regulate transcription. - correct answer ✔✔Which type of
interaction is not a functional mechanism by which lncRNA regulates gene expression?
Lac Y. The lac operon mRNA encodes three proteins. The lacZ produces β-galactosidase, lacY
produces lac permease, and lacA produces lac transacetylase. The lacI is separate and produces
the lac repressor. - correct answer ✔✔Which of the following genes in the lac operon encodes
lac permease?
, Nanog. The pluripotent state is induced by introducing Oct4, Sox2, Klf4, and c-Myc. The stable
epigenetic state is maintained in part by Oct4, Sox2, and Nanog. - correct answer ✔✔Which
transcription factor is NOT used to induce a pluripotent state?
They function as a scaffold for the assembly of large ribonucleoprotein complexes. - correct
answer ✔✔mRNA and lncRNA share several common characteristics. Which of the following are
not characteristics of both mRNA and lncRNA, however?
GAL3. Three proteins are involved in transcriptional regulation of the GAL1 and GAL10 genes in
yeast. GAL3 binds to galactose and blocks the ability of GAL80 to bind GAL4. This allows GAL4 to
activate transcription of GAL1 and GAL10. - correct answer ✔✔Which protein, involved in
regulating GAL1 and GAL10, binds to galactose?
Correct; polymerization of DNA proceeds in the 5'→3' direction. This is because for DNA
polymerases, there must be an available 3'-OH to add on to. This is a vital requirement for the
reaction mechanism of the enzyme. - correct answer ✔✔Which of the following is correct
regarding DNA replication?
Prokaryotic ribosomes have a different structure than eukaryotic ribosomes, so antibiotics that
bind to one cannot bind to the other. - correct answer ✔✔Many organisms produce small
molecules that inhibit bacterial growth, as bacteria can compete for available nutrients and
harm the organism in the process. Natural products with antibacterial properties were first
discovered as secreted products of fungi or other microorganisms growing in culture and were
named antibiotics. The first well-characterized antibiotic was penicillin, which was discovered by
Alexander Fleming in 1928. Even before Fleming's discovery, however, Paul Ehrlich hypothesized
in the early 1900s that it should be possible to synthesize antimicrobial compounds that would
kill pathogenic organisms without harming the host. Why would antibiotics that affect the
ribosome kill bacteria without harming their host?
Correct; this mechanism of DNA repair is called mismatch repair. The E. coli MutS-MutL-MutH
protein complex is responsible for mediating mismatch repair.
graded A+ passed
after transcription initiation but early in elongation - correct answer ✔✔When is the 5′ m7G cap
added to an mRNA transcript?
Ligand binding can have positive and negative control over transcription. Binding of a ligand to a
repressor can either activate the repressor or inactivate the repressor, causing either inhibition
or activation, respectively. Ligand binding to an activator can also either activate or inactivate
the activator, which can turn on or turn off transcription, respectively. - correct answer ✔✔In
the figure below, which situation involves activation under positive control of ligand binding?
Eukaryotes encode a greater variety of ncRNA than prokaryotes. - correct answer ✔✔Which of
these is a difference in the total RNA content of prokaryotes and eukaryotes?
Gyrase - correct answer ✔✔Which replication fork enzyme relieves torsional stress in front of
the fork?
Uncharged tRNA recognition of stop codon in the mRNA - correct answer ✔✔Which of the
following is NOT a part of translational termination?
lncRNA can be translated to produce a ribonucleoprotein complex that binds to DNA and
recruits other protein complexes that regulate transcription. - correct answer ✔✔Which type of
interaction is not a functional mechanism by which lncRNA regulates gene expression?
Lac Y. The lac operon mRNA encodes three proteins. The lacZ produces β-galactosidase, lacY
produces lac permease, and lacA produces lac transacetylase. The lacI is separate and produces
the lac repressor. - correct answer ✔✔Which of the following genes in the lac operon encodes
lac permease?
, Nanog. The pluripotent state is induced by introducing Oct4, Sox2, Klf4, and c-Myc. The stable
epigenetic state is maintained in part by Oct4, Sox2, and Nanog. - correct answer ✔✔Which
transcription factor is NOT used to induce a pluripotent state?
They function as a scaffold for the assembly of large ribonucleoprotein complexes. - correct
answer ✔✔mRNA and lncRNA share several common characteristics. Which of the following are
not characteristics of both mRNA and lncRNA, however?
GAL3. Three proteins are involved in transcriptional regulation of the GAL1 and GAL10 genes in
yeast. GAL3 binds to galactose and blocks the ability of GAL80 to bind GAL4. This allows GAL4 to
activate transcription of GAL1 and GAL10. - correct answer ✔✔Which protein, involved in
regulating GAL1 and GAL10, binds to galactose?
Correct; polymerization of DNA proceeds in the 5'→3' direction. This is because for DNA
polymerases, there must be an available 3'-OH to add on to. This is a vital requirement for the
reaction mechanism of the enzyme. - correct answer ✔✔Which of the following is correct
regarding DNA replication?
Prokaryotic ribosomes have a different structure than eukaryotic ribosomes, so antibiotics that
bind to one cannot bind to the other. - correct answer ✔✔Many organisms produce small
molecules that inhibit bacterial growth, as bacteria can compete for available nutrients and
harm the organism in the process. Natural products with antibacterial properties were first
discovered as secreted products of fungi or other microorganisms growing in culture and were
named antibiotics. The first well-characterized antibiotic was penicillin, which was discovered by
Alexander Fleming in 1928. Even before Fleming's discovery, however, Paul Ehrlich hypothesized
in the early 1900s that it should be possible to synthesize antimicrobial compounds that would
kill pathogenic organisms without harming the host. Why would antibiotics that affect the
ribosome kill bacteria without harming their host?
Correct; this mechanism of DNA repair is called mismatch repair. The E. coli MutS-MutL-MutH
protein complex is responsible for mediating mismatch repair.
