Quiz: Basic Principles of Protein
Score for this attempt: 80 out of 80
Submitted Aug 28 at 2:09pm
This attempt took 79 minutes.
Question 1
2 / 2 pts
What enzyme associated with the urea cycle enzyme is activated by N-
acetylglutamate?
arginase
C !
carbamoyl phosphate synthetase
argininosuccinate synthetase
ornithine transcarbamoylase
glutamate dehydrogenase
Question 2
2 / 2 pts
What sequence is located about 10 bases upstream of the initiation codon?
Meselson-Stahl sequence
C !
Shine-Dalgarno sequence
Watson-Crick sequence
Avery-MacLeod sequence
Hershey-Chase sequence
Question 3
2 / 2 pts
Which of the following initiation steps results in GTP hydrolysis?
binding of IF-2 to the 30S subunit
binding of mRNA to the 30S subunit
binding of IF-1 to the A site
C !
binding of the 50S subunit to the 30S subunit
binding of the fMet-tRNA to the ribosome
Question 4
2 / 2 pts
The interaction used to insure correct codon-anticodon recognition involves
RNA interactions from ________ that specifically check interactions at ________.
mRNA, tRNA and rRNA; second and third codon positions
mRNA and tRNA; second and third codon positions
mRNA and tRNA; first and second codon positions
C !
mRNA, tRNA and rRNA; first and second codon positions
mRNA, tRNA and rRNA; all three codon positions
Question 5
2 / 2 pts
What enzyme catalyzes the conversion of phenylalanine to tyrosine?
phenylalanine decarboxylase
phenylalanine hydrolase
C !
phenylalanine hydroxylase
phenylalanine desaturase
phenylalanine oxidase
Question 6
2 / 2 pts
The codon is found ________ while the anticodon is found ________.
in the mRNA; on the RNA of the ribosome
on the tRNA; on the RNA of the ribosome
C !
in the mRNA; on the tRNA
on the tRNA; in the mRNA
on the proteins of the ribosome; in the mRNA
Question 7
2 / 2 pts
Why does the mRNA adopt a sharp bend as it moves through the ribosome?
in order to maximize base pairing with the 23S rRNA
C !
so the tRNAs in both the A and P site can interact with their appropriate
codons
to prevent dissociation of the 30S and 50S subunits
so that the mRNA can enter the 30S subunit and exit the 50S subunit
all of the above
Question 8
2 / 2 pts
The term rRNA refers to ________ RNA.
C !
ribosomal
recombinant
rho factor
retroviral
Question 9
2 / 2 pts
In E. coli translation, ________ aids with binding of the fMet-tRNA to the 30S
subunit while ________ blocks the A site.
IF-1; IF-3
C !
IF-2; IF-1
IF-1; IF-2
IF-3; IF-1
IF-2; IF-3
Question 10
2 / 2 pts
EF-G is required for ________ as it binds to the ribosome in a manner similar
to ________.
transduction; an aminoacyl-tRNA
C !
translocation; the EF-Tu-tRNA complex
transferase; an uncharged tRNA
transpeptidation; the EF-Tu-GDP complex
none of the above
Question 11
2 / 2 pts
Which of the following amino acids cannot be produced in a plant that has
been treated with glyphosate?
Leu
Cys
Pro
C !
Phe
Arg
Question 12
2 / 2 pts
Which of the following are required by nitrogenase to carry out the reduction
of nitrogen?
an iron-molybdenum cofactor
a strong reducing agent such as ferredoxin
the absence of oxygen
iron-sulfur centers
C !
all of the above
Question 13
2 / 2 pts
Which of the following amino acids is a source of both carbon and nitrogen
for IMP?
C !
Gly
Asn
Gln
Asp
Glu
Question 14
2 / 2 pts
Which of the following is required for the correct charging of a tRNA?
tRNA, amino acid, ATP and transpeptidase
C !
tRNA, amino acid, ATP and aminoacyl-tRNA synthetase
tRNA, mRNA, amino acid, ATP and transpeptidase
tRNA, amino acid, GTP and transpeptidase
tRNA, mRNA, amino acid, GTP and aminoacyl-tRNA synthetase
Question 15
2 / 2 pts
Which of the following neurotransmitters is correctly paired with the amino
acid from which it is synthesized?
serotonin: tryptophan
γ-aminobutyric acid: glutamate
dopamine: tyrosine
epinephrine: tyrosine
C !
all of the above
Question 16
2 / 2 pts
What are the products of the glycine cleavage system?
methyl-tetrahydrofolate and carbamoyl phosphate
formyl-tetrahydrofolate, ammonia and carbon dioxide
methyl-tetrahydrofolate, ammonia and carbon dioxide
C !
methylene-tetrahydrofolate, ammonia and carbon dioxide
methylene-tetrahydrofolate and carbamoyl phosphate
Question 17
2 / 2 pts
What enzyme is responsible for the incorporation of ammonia from nitrogen
fixation into organic molecules?
transaminase
glutamate synthetase
glutamine synthase
glutamate synthase
C !
glutamine synthetase
Question 18
2 / 2 pts
Which of the following best describes the preparation of fMet-tRNA for
translation in prokaryotes?
fMet isn't used in prokaryotes, only in eukaryotes
Met is first formylated, then added to a tRNA specific for the start codon and
differs from the tRNA designed to carry Met
C !
Met is first added to a tRNA specific for the start codon that differs from that
designed to carry Met, then formylated
Met is first formylated, then added to a "regular" tRNAMet; the fact that it has
the formyl group allows use in the initiation codon
Met is first added to a "regular" tRNAMet, then formylated; the fact that it has
the formyl group allows use in the initiation codon
Question 19
2 / 2 pts
The activity of glutamine synthetase is
I. regulated allosterically by tryptophan.
II. inhibited allosterically by glucosamine-6-phosphate.
III. activated by nine allosteric feedback inhibitors.
IV. altered by covalent modification.
I, II
I, III
C !
I, II, III, IV
III, IV
I, IV
Question 20
2 / 2 pts
Which of the following aids in protein folding by completely sequestering a
polypeptide from its environment?
ubiquitin
heat shock protein
signal recognition particle
trigger factor
C !
chaperonin
Question 21
2 / 2 pts
In which cellular location listed below does the following reaction take place?
ornithine + carbamoyl-phosphate → citrulline
C !
mitochondrial matrix
lysosome
cytosol
A and B
none of the above
Question 22
2 / 2 pts
Which of the following explains why the aminoacyl-tRNA synthetase for
isoleucine rarely incorporates valine despite the similar structure of these
two amino acids?
C !
the enzyme contains a proofreading site that only excludes isoleucine
the enzyme contains a proofreading site that only allows isoleucine
only leucine and isoleucine can fit in the active site of the enzyme
valine does not fit into the binding site for isoleucine
none of the above
Question 23
2 / 2 pts
Which amino acid is the first incorporated into a prokaryotic protein?
N-formylcysteine
C !
N-formylmethionine
N-formylglutamine
N-formylaspartate
N-formylthreonine
Question 24
2 / 2 pts
The conversion of IMP to AMP requires ________; the conversion of IMP to GMP
requires ________.
C !
Asp; Gln
Gln; Glu
Asn; Asp
Glu; Asn
Asp; Glu
Question 25
2 / 2 pts
Which of the following occurs during the post-translational processing of
insulin?
glycosylation
acetylation of lysine residues
phosphorylation
amidation of the C-terminal amino acid
C !
formation of disulfide bonds
Question 26
2 / 2 pts
Given the following anticodon, which mRNA codon would pair with it?
5′-IGC-3′
5′-UCG-3′
5′-ACU-3′
5′-GUA-3′
5′-UCA-3′
C !
5′-GCU-3′
Question 27
2 / 2 pts
Transfer RNA molecules are involved in ________.
replication
C !
translation
reverse transcription
post-translational processing
transcription
Question 28
2 / 2 pts
Which of the following tRNA binding sites is correctly defined?
T site: site that is briefly occupied while the tRNA is passed from the A site to
P site
E site: entrance site for initial tRNA binding
P site: site occupied by the tRNA that accepts the growing peptide chain
C !
A site: accepts incoming aminoacyl-tRNA
all of the above
Question 29
2 / 2 pts
What two elements of translation are paired by a Shine-Dalgarno sequence?
mRNA with initial tRNA
initial tRNA with the initiation codon
initial tRNA with the ribosomal A site
mRNA with 23S rRNA of the ribosome
C !
mRNA with 16S rRNA of the ribosome
Question 30
2 / 2 pts
Which of the following antibiotics mimics an aminoacyl-tRNA?
chloramphenicol
penicillin
streptomycin
C !
puromycin
erythromycin
Question 31
2 / 2 pts
Which of the following citric acid cycle intermediates can be converted to
aspartate via transamination?
succinate
C !
oxaloacetate
citrate
fumarate
α-ketoglutarate
Question 32
2 / 2 pts
How many ATP and electrons are required for the reduction of one molecule
of nitrogen to two molecules of ammonia in the reaction catalyzed by
nitrogenase?
C !
16 ATP and 8 electrons
8 ATP and 16 electrons
8 ATP and 8 electrons
16 ATP and 6 electrons
16 ATP and 16 electrons
Question 33
2 / 2 pts
In the process of nitrification, nitrate reductase converts ________ into
________.
nitrate; ammonia
C !
nitrate; nitrite
nitrate; nitric oxide
nitrate; nitrogen
nitrogen; nitrate
Question 34
2 / 2 pts
The genetic code is said to be ________ because several codons may
correspond to the same amino acid.
decadent
deteriorate
C !
degenerate
despicable
depraved
Question 35
2 / 2 pts
In which cellular location listed below does the following reaction take place?
arginine → urea + ornithine
mitochondrial matrix
lysosome
C !
cytosol
A and B
none of the above
Question 36
2 / 2 pts
What are the predominant interactions between the 30S and 50S subunits
that allow the formation of the 70S ribosome?
interactions of 50S rRNA with tRNA D loop and interactions of 30S rRNA with
anticodon loop are the only interactions holding the 70S ribosome together
30S protein with 50S rRNA
protein-protein interactions from both subunits
C !
rRNA-rRNA interactions from both subunits
30S rRNA with 50S protein
Question 37
2 / 2 pts
Which of the following is formed as a result of pyrimidine metabolism?
aspartate
C !
β-alanine
glycine
alanine
asparagine
Question 38
2 / 2 pts
Which of the following is the only tRNA loop that is exclusively single
stranded RNA?
TψC loop
anticodon loop
D loop
acceptor step
C !
none of the above
Question 39
2 / 2 pts
What do birds excrete as nitrogen waste instead of urea?
citrulline
carbamoyl phosphate
C !
uric acid
asparagine
arginine
Question 40
2 / 2 pts
What form of the folate coenzyme is required for the conversion of
homocysteine to methionine?
dihydrofolate
methylene-tetrahydrofolate
formyl-tetrahydrofolate
C !
methyl-tetrahydrofolate
methenyl-tetrahydrofolate
Quiz Score: 80 out of 80
