Biology 251 - Genetics » Spring 2021 » Exam 4
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Question #1
An operon regulated by a repressor protein that is normally off, but is switched on in the presence of a small molecule is under:
A.
positive, repressible regulation.
B.
negative, repressible regulation.
C.
negative, inducible regulation.
D.
positive, inducible regulation.
Question #2
Coordinated regulation of genes that encode proteins or enzymes that function in the me cellular process is achieved in bacteria, but not eukaryotes by organization of these genes as operons producing polycistronic mRNAs.
A.
True
B.
False
Question #3
DNA methylation for regulation of gene expression in eukaryotes primarily occurs on:
A.
C residues in the sequence CpG.
B.
A residues in the sequence GATC.
C.
C residues in the sequence CCGG.
D.
A residues in the sequence GAATTC.
Question #4
Some species of birds have colored patterns in their feathers that attract mates of opposite phenotypes. The mating of birds with different feather patterns is an example of:
A.
natural selection.
B.
positive assortative mating.
C.
inbreeding.
D.
negative assortative mating.
E.
genetic drift.
Question #5
Term for an evolutionary process resulting in a change in allele frequency due to environmental conditions favoring more fit genotypes.
A.
natural selection
B.
inbreeding
C.
genetic drift
D.
positive assortative mating
E.
negative assortative mating
Question #6
TFIID and TFIIB are called general transcription factors and form the basal transcription apparatus with RNA polymerase II.
A.
False
B.
True
Question #7
The type of regulation that regulates transcription activation for an operon using a repressor protein is
A.
repressible regulation.
B.
coordinate regulation.
C.
negative regulation.
D.
positive regulation.
E.
inducible regulation.
Question #8
Which of the following is true for eukaryotic gene regulation, but not bacterial regulation?
A.
genes encoding enzymes in the same biochemical pathway are organized in a transcription unit
B.
repressor proteins bind to sites that block RNA polymerase binding for initiation of transcription.
C.
repression is primarily achieved through chromatin condensation
D.
gene expression is regulated by the presence of small molecules or other environmental cues
Question #9
The histone octamer includes two copies of all of the histones below except:
A.
H2A.
B.
H4.
C.
H1.
D.
H2B.
E.
H3.
Question #10
Typically, mRNA turnover in eukaryotes predominantly occurs through the
A.
endonucleolytic pathway that starts with internal cleavage of the mRNA by the endonculease Dicer..
B.
decapping pathway that starts with removal of the 5' 7-methylguanosine cap..
C.
deadenylation pathway that starts with degradation of the polyA tail..
D.
endonucleolytic pathway that starts with internal cleavage by the RNA-induced silencing complex.
Question #11
An end-product of a biochemical pathway that allosterically binds a repressor to cause a conformation changeto the protein-binding state functions as:
A.
a corepressor.
B.
an activator.
C.
an inducer.
D.
a coactivator.
E.
a repressor.
Question #12
The type of regulation that regulates transcription activation for an operon using an activator protein is
A.
repressible regulation.
B.
inducible regulation.
C.
positive regulation.
D.
coordinate regulation.
E.
negative regulation.
Question #13
An enzyme associated with gene activation through histone tail modifications is:
A.
histone acetyl transferase (HAT).
B.
Mediator.
C.
histone deacetylase (HDAC).
D.
chromatine remodeling complex.
E.
histone methyl transferase.
Question #14
Gene expression where the gene is normally “off” and turned “on” by presence of small molecule product of a biochemical synthesis pathway would be described as
A.
repressible regulation.
B.
positive regulation.
C.
inducible regulation.
D.
negative regulation.
Question #15
Post-translational modification of histone tails to compact DNA into heterochromatin involves modification of histone lysines with:
A.
acetylation
B.
phosphorylation
C.
carboxylation
D.
methylation
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