Bioc 385 Final Exam || with 100% Accurate Solutions.
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Course
Bioc 385
Institution
Bioc 385
Tyr122 is important in the mechanism of the E. coli ribonucleotide reductase. The function of this amino acid in the mechanism is to
carry out a nucleophilic attack on the substrate.
coordinate water in the active site.
generate the Cys439 radical species.
hydrogen-bond to the phosphates of t...
Bioc 385 Final Exam || with 100% Accurate Solutions.
Tyr122 is important in the mechanism of the E. coli ribonucleotide reductase. The function of
this amino acid in the mechanism is to
carry out a nucleophilic attack on the substrate.
coordinate water in the active site.
generate the Cys439 radical species.
hydrogen-bond to the phosphates of the substrate. correct answers generate the Cys439 radical
species.
Which of the following is the reaction for nitric oxide synthase?
They have conserved primary sequences.
They are not true catalysts.
They are transcription factors.
They have conserved secondary and tertiary structures. correct answers They have conserved
secondary and tertiary structures.
In the chloroplasts, photosystem I (PSI) and photosystem II (PSII) are known to localize in
different regions. PSI generally localizes in the __________, whereas PSII localizes in the
__________.
thylakoid lumen; thylakoid grana
thylakoid lamellae; thylakoid grana
stroma; thylakoid lumen
thylakoid grana; thylakoid lamellae correct answers thylakoid lamellae; thylakoid grana
The herbicide paraquat operates by stealing electrons from photosystem I (PSI). Which of the
following is true of chloroplasts treated with paraquat?
NADPH levels drop.
Photosystem II is not re-reduced.
Plastocyanin has nowhere to donate electrons.
No protons are pumped across the chloroplast membranes. correct answers addition of a poly(A)
tail.
One of the functions of the lipid rafts is to
,act as a storage mechanism for fatty acids.
control fluidity of the membrane.
coordinate cell signaling.
maintain sodium levels in the cell. correct answers coordinate cell signaling.
The C-terminal domain (CTD) of the eukaryotic RNA polymerase II is involved in the
transcriptional process of
addition of a poly(A) tail.
removal of exons.
directing RNA to the cytoplasm.
product phosphorylation. correct answers addition of a poly(A) tail.
The introduction of 14CO2 into a cell actively synthesizing fatty acids results in 14C labeled
malonyl-CoA.
acetyl-CoA.
acyl-CoA.
palmitate. correct answers malonyl-CoA.
A person unable to produce new melanocytes is likely to have
black hair.
red hair.
gray hair.
hair loss. correct answers gray hair.
Consider an in vitro experiment in which all components needed for protein synthesis are
present. If tRNAs charged with radioactively labeled amino acids are added, over time the
radioactivity would be located in which of the following components?
mRNA
aminoacyl tRNA synthetase
nascent protein
codons correct answers nascent protein
In yeast, the number of tRNA genes is __________ the number of __________.
equivalent to; amino acids
less than; amino acids
equivalent to; mRNAs
greater than; codons correct answers less than; amino acids
Noncanonical base pairings of A and I would contain __________ hydrogen bonds. The base
pairing of C and I would contain __________ hydrogen bonds.
1; 3
1; 2
2; 2
2; 1 correct answers 2; 2
,Identify the polyunsaturated fatty acid. correct answers
Which of the following do -oxidation and fatty acid synthesis have in common?
the presence of an oxidized fatty acyl -carbon with a hydroxyl or carbonyl group as a pathway
intermediate
their cellular location
their use of NADH
the number of enzymes involved in the pathways correct answers the presence of an oxidized
fatty acyl -carbon with a hydroxyl or carbonyl group as a pathway intermediate
Gene expression can be controlled by the modification of histones by all of the following
EXCEPT
phosphorylation.
methylation.
acetylation.
glycosylation. correct answers glycosylation.
A possible outcome if E. coli was depleted in NADPH would be
buildup of lysine.
depletion of asparagine.
buildup of aspartate.
depletion of methionine. correct answers depletion of methionine.
What will happen to the lac operon when there are elevated levels of glucose in a cell?
CRP binds strongly.
Transcription occurs at a very high rate of expression.
Transcription occurs at a very low rate of expression.
The lac repressor is bound. correct answers Transcription occurs at a very low rate of expression.
Which sequence is MOST likely to be modified with the fatty acid myristoylate in the ER?
(The ... represents additional amino acids N-terminal to those shown.)
Cys-Leu-Ala-Ile-Ser-Phe...
Leu-Gly-Phe-Ala-Ser-Phe...
Gly-Leu-Phe-Ala-Ile-Ser...
Phe-Leu-Cys-Gly-Leu-Ile... correct answers Gly-Leu-Phe-Ala-Ile-Ser...
How are double bonds added to fatty acid chains in humans?
The smooth endoplasmic reticulum is involved in elongating and unsaturating fatty acids.
FAD is used as an oxidant to create the double bonds in the smooth endoplasmic reticulum.
Unsaturated fatty acids are not made by humans and are therefore essential fats.
Fatty acid desaturase enzymes use O2 and NADH to add double bonds to fatty acids. correct
answers Fatty acid desaturase enzymes use O2 and NADH to add double bonds to fatty acids.
The initiation of transcription in eukaryotes
occurs in the same manner as prokaryotic transcription.
, requires the complete unfolding of the gene into single-stranded DNA.
requires many more transcription factors than prokaryotic transcription.
uses RNA polymerase as well as helicase and primase. correct answers requires many more
transcription factors than prokaryotic transcription.
An experimental prep is able to separate the following membrane fractions: nuclear membrane,
Golgi apparatus membrane, transport vesicle membrane, and mitochondrial membrane. The
membrane fractions can then be analyzed via Western blotting for the presence of specific
proteins. Which fraction would indicate the presence of t-SNAREs?
nuclear membrane
Golgi apparatus membrane
transport vesicle membrane
mitochondrial membrane correct answers Golgi apparatus membrane
Analysis of various cell types after exposure to insulin would show an increase in triacylglycerol
synthesis in which of the following?
brain
skeletal muscle
liver
pancreas correct answers liver
Contrast the binding of nucleotides to the activity site and specificity site on the R1 subunit of E.
coli ribonucleotide reductase by choosing the nucleotide that can bind to the specificity site but
NOT the activity site.
ATP
dTTP
dATP
dCDP correct answers dTTP
Nitrogen in biological compounds ultimately comes from what source?
ammonia
nitrate
nitrogen gas
bacteria correct answers nitrogen gas
cis 16:2 (3,5) correct answers
In negative autoregulation,
proteins activate their own expression.
proteins repress their own expression.
a regulatory protein controls DNA expression.
a regulatory protein turns off DNA expression. correct answers proteins repress their own
expression.
Cytoplasmic levels of NADH must be maintained in order for gluconeogenesis to occur. What
generates NADH for this pathway?
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