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BIOC 385 Final with Questions

Terms in this set (148)

The chloroplast contains a highly folded membrane called the
thykaloid
lumen.
inner membrane.
matrix.
The O2 generated from photosynthesis is derived from
CO2 reduction to glyceraldehyde-3-phosphate.
CO2 reduction to glycerate-3-phosphate.
water molecules that directly reduce PSI*.
water molecules that directly reduce PSII*.
For photosynthesis, sunlight energy drives electron transfer. From where are the electrons ejected when light is absorbed?
photons released by chlorophyll
NADPH
light-harvesting pigments in PSI and PSII
oxygen
Resonance energy transfer from one chlorophyll in the photosystems results in
a reduced neighboring pheophytin molecule.
a neighboring chlorophyll in an excited state.
heat release.
the release of a photon.
What group in photosystem II (PSII) directly reacts with H2O during its light-driven oxidation?
oxygen-evolving center
P680
tyrosine
pheophytin
During photophosphorylation, the protons are pumped into the ___________, and the ATP is made in the ___________.
thylakoid lumen; cytoplasm
thylakoid lumen; stroma
stroma; thylakoid lumen
cytoplasm; stroma
what location of the cell does the Calvin-Benson cycle occur?
chloroplast grana
thylakoid lumen
chloroplast stroma
cytoplasm
The first stage of the three-stage Calvin-Benson cycle
generates CO2.
uses ATP and NADPH from the light reactions.
occurs in the plant cell's cytoplasm.
is catalyzed by the enzyme RuBisCO.
The third stage of the three-stage Calvin-Benson cycle
uses ATP and NADPH from the light reactions.
generates a glucose molecule for the plant.
is similar to the reactions found in the glycolysis pathway.
regenerates a C5 sugar for the Calvin-Benson cycle to continue.
Overall, the net balanced reaction of the Calvin-Benson cycle converts three CO2 molecules into one
ribulose-5-phosphate.
glyceraldehyde-3-phosphate.
acetyl-CoA.
glucose.
Ribulose bisphosphate carboxylase (RuBisCO)
is the most abundant enzyme in the biosphere, comprising as much as 50% of plant cell protein.
catalyzes the reaction of C5 molecule and CO2 with a C6 sugar product.
is located in the thylakoid lumen.
requires NADPH and ATP to fix CO2.
Which statement regarding CAM plants is true?
They use one cell type to absorb and store CO2 before utilizing it in the Calvin-Benson cycle in another cell type.
They are more efficient than C4 plants.
They absorb CO2 at night and release it to the Calvin-Benson cycle during the day.
They store CO2 in 3-phosphoglycerate before releasing it to the Calvin-Benson cycle.
Which glycan is a major component of plant cell walls?
cellulose
chitin
keratin sulfate
glycogen
Which glucose homopolymer would be used if a person had to sprint quickly?
Sucrose
galactose
Starch
glycogen
What is one of the functions of polysaccharides?
enzymatically removing glycans through hydrolysis reactions functioning as a structural component in invertebrate exoskeletons acting as metabolic intermediates in glycolysisenzymatically linking glycans to proteins and lipids
Raffinose-series oligosaccharides are hard for humans to digest because
humans do not have the enzyme necessary to hydrolyze the glycosidic bonds.
they bind to bifidobacteria in the gut.
they function as soluble decoys that inhibit pathogenic bacteria from invading the epithelial cells.
humans have a large number of competing glycan binding sites.
A person who only expresses the GTA enzyme and not the GTB enzyme will have which blood type?
O
A
B
AB
A person who only expresses the GTB enzyme and not the GTA enzyme will have which blood type?
O
A
B
AB
What is the blood type of a person who fails to express either the GTA or GTB glycosyltransferases?
O
A
B
AB
The pentose phosphate pathway occurs in the
cytoplasm.
nucleus.
Golgi apparatus.
mitochondria.
Which of the following metabolites has carbon atoms that can end up in glucose via the gluconeogenesis pathway in humans?
CO2
glycerol
ATP
NADH
Which pathway is the opposite of gluconeogenesis in its final product?
TCA cycle
glycogen synthesis pathway
pentose phosphate pathway
glycolysis pathway
Gluconeogenesis would most likely be allosterically activated simultaneously along with which other metabolic process?
glycolysis
pentose phosphate pathway
glycogen synthesis
TCA cycle
What triggers the Cori cycle?
a buildup of cellular NAD+
oxygen-limited working muscle cells
low levels of glucose in the muscle cells
elevated glucagon levels
The branching enzyme of glycogen synthesis is involved in
making the α(1,6) branch points.
making α(1,4) linkages at the branch points.
breaking the α(1,6) branches and smoothing out the glycogen chain.
transferring ~3 glucose units from a branch point to the end of a growing glycogen chain.
Which statement of the debranching enzyme is true?
It catalyzes the addition of free glucose to a nonreducing end of glycogen.
Its product is glucose-1-phosphate.
It evenly distributes branch points across the glycogen polymer.
It is one enzyme with three unique catalytic activities.
The role of glycogenin is to
catalyze the formation of UDP-glucose.
act as a hormone to regulate glucose levels.
serve as the origin of the glycogen polymer.
enable glycogen to fold properly.
The hormone insulin stimulates ___ and inhibits _____, leading to a(n) ____ in the glucose levels.
glycogen synthase; glycogen phosphorylase; decrease
glycogen phosphorylase; glycogen synthase; decrease
glycogen synthase; glycogen phosphorylase; increase
glycogen phosphorylase; glycogen synthase; increase
fatty acid that has more than one double bond is referred to as
monosaturated.
monounsaturated.
polysaturated.
polyunsaturated.
Classify the fatty acid shown below
saturated
unsaturated
monounsaturated
polyunsaturated
In addition to triacylglycerols, which other lipid synthesized in the liver is transported by VLDLs?
sphingophospholipid
cerebroside
ganglioside
cholesterol
Predict the fatty acid with the lowest melting point
trans 14:1 (Δ7)
cis 14:2 (Δ7,9)
trans 14:2 (Δ7,9)
cis 14:3 (Δ7,9,11)
VLDLs are produced in
liver cells.
intestinal epithelial cells.
stomach cells.
adipocytes.
Which particles transport triacylglycerols to adipose tissue for storage?
apolipoproteins
adipocytes
chylomicrons
perilipin
Snake venoms often contain phospholipase A enzymes, which cleave glycerophospholipids in humans. Why is snake venom with phospholipase A enzymes often toxic to humans?
There is a buildup of GM2 ganglioside in the spleen and brain.
Tissue is damaged from the detergent effect of free fatty acids.
Sphingomyelin levels are elevated, resulting in cell death.
Ceramide trihexoside accumulates, causing a heart attack.
One advantage of using hydrogenation in the food industry is
decreased processing time.
reduction in heart disease.
increased shelf life.
decreased melting point.
The water-soluble enzyme in the small intestine that hydrolyzes the acyl ester bonds in triacylglycerols is
adipocyte.
albumin.
lipase.
colipase.
Triacylglycerols are transported though the blood as
glycerophospholipids.
sphingolipids.
cerebrosides.
very-low-density lipoprotein particles.
Lipid rafts are thought to be discrete membrane regions that contain high concentrations of
phosphatidylinositol.
gangliosides.
phosphatidylcholine.
cholesterol.
Free fatty acids released from adipose tissue are transported throughout the body by a carrier protein called
adipocyte.
albumin.
lipase.
colipase.
Partial hydrogenation can result in the formation of
ω-3 fatty acids.
ω-6 fatty acids.
cis double bonds.
trans double bonds.
Chylomicrons are produced in
liver cells.
intestinal epithelial cells.
stomach cells.
adipocytes.
What is the key enzyme involved in priming fatty acids for degradation?
acetyl-CoA carboxylase
fatty acyl-CoA synthetase
carnitine acyltransferase I
fatty acyl hydrolase
Which enzyme is responsible for assembly of palmitate from activated acetyl-CoA fragments?
acyl-CoA dehydrogenase
acetyl-CoA carboxylase
fatty acyl-CoA synthetase
fatty acid synthase
What is the cellular location of the fatty acid oxidation pathway?
cytoplasm
peroxisome
mitochondrial matrix
smooth endoplasmic reticulum
Which molecule is used to transport fatty-acyl groups into the mitochondria?
CoA-SH
ATP
biotin
carnitine
In order for a fatty acyl-CoA to be moved into the mitochondria for β-oxidation, it must be
transported by the carnitine-acylcarnitine translocase.
activated by ATP.
reduced by NADH and FADH2.
hydrolyzed into acetyl-coA fragments.
Which of the following are ketone bodies?
- acetyl-CoA, hydroxymethylglutaryl-CoA
- β-ketoacyl-ACP , hydroxymethylglutaryl-CoA
- methylmalonyl-CoA, acetyl-CoA
- hydroxybutyrate, acetoacetate
Both the synthesis and β-oxidation of saturated fatty acids
require FAD.
require NADPH.
occur in the cytosol.
involve acetyl-CoA.
The same four reactions that are central to the β-oxidation pathway are also present in the fatty acid synthesis pathway, except they are reversed. What is a key difference between the four reactions in these two pathways?
One set of reactions synthesizes an ATP, whereas the other set uses an ATP.
One set occurs in the muscle, whereas the second pathway occurs in the liver.
One pathway adds three carbon atoms at a time, whereas the other removes two carbons.
Four enzymes are used in one, whereas one enzyme is used in the other.
What enzyme catalyzes the following reaction in the first step of fatty acid synthesis?
fatty acyl-CoA synthetase
acetyl-CoA carboxylase
fatty acid synthase
fatty acyl-CoA dehydrogenase
What cofactor, common to carboxylase enzymes, is used by acetyl-CoA carboxylase?
NADPH
FAD
biotin
pyridoxal phosphate
Which is true of the acyl carrier protein (ACP)?
It transports the fatty acid chain during oxidation and synthesis.
It directs the growing fatty acid chain from one enzyme active site to another in the fatty acid synthesis
pathway.
It requires ATP for proper function.
It catalyzes the delivery of fatty acyl chains from the mitochondria to the cytosol.
The acetyl-CoA for fatty acid synthesis comes from the
breakdown of fats.
TCA cycle.
mitochondria via the citrate shuttle.
breakdown of cytoplasmic pyruvate.
Which of the following stimulate fatty acid synthesis when their concentrations are high?
citrate and insulin
glucagon and citrate
insulin and acyl-CoA
citrate, insulin, and palmitoyl-CoA
Which of the following is a possible fate for cholesterol synthesized in the liver?
used in the synthesis of chlorophylls
packaged into lipoproteins and exported to circulatory system
packaged into lipids and exported to the brain
used in the synthesis of nucleotides
Increasing bile acid excretion by the body has which effect on overall cholesterol levels?
increases recycling of cholesterol by the liver
increases cholesterol levels
lowering cholesterol levels
decreases level of cholate
During the conversion of VLDL to IDL, the
IDL becomes increasingly enriched in cholesterol.
core of IDL becomes increasingly enriched in TAGs.
LDL intermediate is formed.
IDL becomes depleted of protein.
Which of the following lipoproteins functions to transport cholesterol from the peripheral tissues to the liver?
VLDL
LDL
HDL
chylomicron
By what process are LDL particles removed selectively from the blood serum?
through targeted digestion by serum lipases
by receptor-mediated endocytosis
They are replenished with triacylglycerols and never removed.
They form atherosclerotic plaques.
Which lipid is thought to give rise to the plaques that can clog arteries?
HDL
LDL
VLDL
chylomicrons
LDLs are referred to as "bad cholesterol" because
they are the blood serum particle with the highest concentration of cholesterol.
they contain cholesterol that is not as easily degraded.
their cholesterol has no specific cellular purpose other than to form plaques.
LDL levels surge after meals high in fat.
The sterol regulatory element (SRE) is a(n) ________ and the sterol regulatory element binding protein (SREBP)
is a(n) ________.
allosteric activator; enzyme
transport activator; transport protein
receptor; hormone
DNA promoter; transcription activator
Statin drugs bind to which enzyme in the cholesterol biosynthetic pathway?
HMG-CoA reductase
LDL receptor
HMG-CoA synthase
cholesterol esterase
The 10 amino acids that animals need to take in through their diet are called the _______ amino acids.
common
essential
optional
degradation
Nitrogen in biological compounds ultimately comes from what source?
ammonia
nitrate
nitrogen gas
bacteria
The process of nitrogen fixation reduces N2 to
NAD+.
nitrate.
ammonia.
nitrite.
How does biological fixation convert nitrogen to ammonia?
by oxidizing nitrogen
by combining nitrogen with carbon
through the ATP-dependent process catalyzed by nitrogenase complex
through the NADH-dependent process catalyzed by glutamate dehydrogenase
How does atmospheric fixation occur given the high energy barrier for converting nitrogen to nitrogen oxides?
through the oceans that break the triple bond of nitrogen and allow for the combination with water
through clouds that allow for nitrogen to combine with oxygen
in the soil by bacteria that reduce nitrogen to ammonia
through lightning that breaks the triple bond of nitrogen and allows for the combination with oxygen
If plants and bacteria were unable to produce glutamate from ammonia, a possible outcome would be that plants would
be able to produce more nucleotides.
no longer be able to produce other amino acids.
not be able to complete glycolysis.
be able to produce more ATP.
Aminotransferase reactions operate at ΔG °' ≈ 0. What occurs when there is high substrate availability?
More reactants are produced.
More products are produced.
Equal amounts of products and reactants are produced.
This reaction is thermodynamically unfavorable.
Nitrogen balance is best described as when the daily intake of _______ equals the amount of ________ lost by excretion
ammonia; nitrogen
nitrogen; nitrogen
glucose; glucose
nitrogen; ammonia
A negative nitrogen balance in a person would be an indicator of
accumulation of nitrogen in the body.
a diet heavy in protein.
starvation.
overall good health.
It is important for proteolytic enzymes in the lysosome to be optimized to work at low pH because low pH
enhances protein denaturing.
deactivates cysteine proteases.
makes it easier for ATP to be converted to ADP + Pi.
enhances the degradation of ubiquitinated proteins.
Eukaryotic proteasome selectively degrades which type of proteins?
all proteins; it is not selective
ubiquitinated proteins
phosphorylated proteins
ATP-dependent proteins
The two mechanisms to regulate protein ubiquitination are biochemical changes to
target proteins and El ligases.
E1 and E2 ligases.
target proteins and E3 ligases.
the E2-ubiquitin-E3 complex.
The urea cycle's function is to _______ the body of an organism.
remove excess sugar from
remove excess water-soluble vitamins from
remove excess nitrogen from
add additional nitrogen to
Which intermediate is shared by the urea cycle and the citric acid cycle?
citrulline
argininosuccinate
aspartate
malate
What is a possible outcome to the urea cycle if the cell is unable to produce enough aspartate?
Flux would be accelerated through the cycle.
There would be a buildup of citrulline.
There would be a buildup of urea.
The cycle would maintain equilibrium.
Aspartate is a nonessential amino acid. A nonessential amino acid means that
without this amino acid in the diet, death would occur.
aspartate could be synthesized from other intermediates.
aspartate could be synthesized directly from pyruvate.
without this amino acid, ketosis would occur.
Arginine, leucine, and lysine are all essential amino acids. This means that they are
only available from a person's diet.
produced from other intermediates.
not needed for a body to function.
the main intermediates to the urea cycle.
Jaundice is indicative of what process working inefficiently?
heme synthesis
bilirubin removal from blood
urea synthesis
amino acid degradation
People at risk of heart attacks often carry nitroglycerin pills with them. What effect would ingesting nitroglycerin pills have?
releases NO rapidly for blood vessel dilation
releases ammonia for rapid muscle relaxation
inhibits acetylcholine release from neurons
inhibits cGMP phosphodiesterase
Which of the following is a role of nucleotides in cells?
energy conversion reactions
glycolysis
nitrification
proteolysis
Which of the following is a benefit of nucleotide salvage pathways compared with de novo synthesis?
increased variety of nucleotides produced
increased half-life of mRNA
reduced energy expenditure
decreased regulation of nucleotide homeostasis
The biosynthesis of deoxynucleosides is important, yet different organisms require different sets of enzymes to carry it out. If 100 different species were analyzed, which enzyme is most likely to be found in all of them?
ribonucleotide reductase
thioredoxin
glutaredoxin
glutathione reductase
What biomolecules can skeletal muscle use as metabolic fuel?
glucose, free fatty acids, and chylomicrons
chylomicrons, free fatty acids, and ketone bodies
chylomicrons, glucose, and ketone bodies
ketone bodies, free fatty acids, and glucose
Which organ is responsible for regulating physiological levels of glucose?
liver
muscle
adipose tissue
brain
Metabolic homeostasis relies on maintaining
maximum ATP synthase activity.
optimal metabolite concentrations.
maximum flux through the citric acid cycle.
minimal inhibition of gluconeogenesis.
Which tissue participates in the Cori cycle in order to maintain metabolic homeostasis?
skeletal muscle
adipose tissue
kidney
brain
Which tissue participates in the triacylglycerol cycle in order to maintain metabolic homeostasis?
skeletal muscle
liver
kidney
brain
Which of the following activates triacylglycerol hydrolysis and fatty acid export in adipose tissue?
insulin
glucagon
somatostatin
LpL
Glucagon stimulates glucose export by increasing metabolic flux through gluconeogenesis in the
liver.
skeletal muscle.
adipose.
brain.
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
PPARγ-regulated gene expression results in
the upregulation of inflammatory cytokines.
increased insulin sensitivity.
reduced fatty acid transport.
decreased insulin sensitivity.
Positive or negative _______________ is(are) determined by the energy content of foods and the energy that is expended through processes such as physical exertion.
dietary balance
thermodynamic balance
energy balance
thermogenic processes
The graph on the right shows the relative changes in concentration of glucose, fatty acids, and ketone bodies during 40 days of starvation. Choose the answer that correctly labels the data on the graph.
X = fatty acids; Y = glucose; Z = ketone bodies
X = glucose; Y = fatty acids; Z = ketone bodies
X = ketone bodies; Y = glucose; Z = fatty acids
X = ketone bodies; Y = fatty acids; Z = glucose
Which of the following changes in metabolic flux would be expected to occur during long periods without food?
decreased release of fatty acids from adipose tissue
decreased gluconeogenesis in liver and kidney cells
decreased ketogenesis in liver cells
protein degradation in skeletal muscle
If calorie input is greater than calorie output, then an individual has a/an _________ energy balance.
negative
neutral
incomplete
positive
If calorie input is less than calorie output, then an individual has a/an _________ energy balance.
negative
neutral
incomplete
positive
Human gene variants favoring individuals with a capacity to store extra fat during times of feast are known as
Neel variants.
thrifty genes.
leptos genes.
Pima variants.
Thrifty genes are ________ during times of starvation and ________ when physical activity is low.
beneficial; beneficial
beneficial; detrimental
detrimental; detrimental
detrimental; beneficial
You are evaluating a patient that is exhibiting signs of diabetes. You are monitoring their blood glucose levels after an insulin injection. You would expect the patient to be insulin ________ if they had type 1 diabetes and insulin ________ if they had type 2 diabetes.
resistant, sensitive
sensitive, resistant
resistant, resistant
sensitive, sensitive
Semiconservative, as it relates to DNA replication, can be defined as occurring when the original duplex DNA template
remains intact to make a new DNA duplex.
is broken into fragments.
is separated into single strands before replications.
can only be replicated once.
The figure to the right shows the DNA polymerase reaction. Identify B.
lagging strands
template DNA strands
template RNA strands
leading strands
The figure from question 106 shows the DNA polymerase reaction. Identify A.
lagging strands
template DNA strands
template RNA strands
leading strands
The 3'-hydroxyl group used to initiate DNA synthesis usually comes from
an RNA primer.
the magnesium ion.
uracils.
amino acids.
DNA polymerase does not make mismatched base pairs because
there are no hydrogen bonds that line up between the mismatches.
the active site does not fit mismatches well.
the mismatched pairs make covalent bonds instead of hydrogen bonds.
the DNA primer does not allow for mismatched pairs.
Which of the following functions does a reverse transcriptase perform?
proofreading
exonuclease activity
copies RNA to DNA
copies DNA to RNA
The complete complex that contains the enzymes and proteins required to replicate DNA is called the
primase.
polymerase.
replisome.
DNA gyrase.
Why do helicase and gyrase need to work together?
Gyrase adds the RNA primer and helicase removes it.
Helicase unwinds DNA and gyrase relieves the torsional strain.
Helicase synthesizes DNA and gyrase prevents helicase from dissociating.
Gyrase synthesizes RNA primers and helicase.
Eukaryotic genomes overcome the slow synthesis rate by
eliminating the need for unwinding the DNA.
providing more replication origins.
using multiple primases.
only replicating part of the DNA in one cycle.
Which of the following would cause a genetic mutation?
DNA makes too many copies in the cell.
DNA synthesis does not occur.
DNA damage is not corrected.
Death of a cell occurs.
The most common DNA mutation is the substitution of one base for another. What is the likely outcome from that mutation?
increased DNA replication
an alteration of the protein's coding sequence
prevention of further synthesis
cell death
Most cancers are caused by which kind of DNA mutation?
base substitution
abasic site
somatic
nucleotide deletions
In what stage of the cell cycle does homologous recombination largely occur?
G1
S
G2
meiosis
DNA crossover is important during meiosis because it allows
the organization of genes on the chromosome to change.
DNA repair to occur.
the exchange of genetic information.
base excision to occur.
A 7-methylguanylate cap and poly(A) tail is added to mRNA to
differentiate the mRNA from the tRNA.
facilitate binding and translation by the ribosome.
increase mRNA splicing efficiency.
signify the start and end of the gene sequence.
What do σ factors bind to in RNA synthesis?
DNA promoters and RNA polymerase
RNA promoters and DNA
DNA and RNA
transcription factors
What do group I introns require that group II introns do not?
ATP hydrolysis
metal ion cofactors
guanosine cofactor binding
external RNA substrate
The initiation, elongation, and termination of eukaryotic transcription is controlled by the
extent of phosphorylation and dephosphorylation of the RNA polymerase.
presence of initiation, elongation, and termination factors binding to RNA polymerase.
unwinding the double-stranded DNA.
length of the RNA transcript.
What are σ factors in RNA synthesis?
DNA promoter regions
RNA polymerases
transcription factors
receptor proteins
The C-terminal domain (CTD) of the eukaryotic RNA polymerase II is required for coordinating precursor mRNA processing and its functions are regulated by
the addition of a poly(A) tail.
the removal of exons.
directing RNA to the cytoplasm.
phosphorylation and dephosphorylation.
Which is often removed from eukaryotic mRNA before translation?
poly(A) tails
exons
polycistrons
introns
What is the difference between eukaryotic and prokaryotic promotors? Only eukaryotic promoters
are located before the transcription start site.
bind transcription factors.
are located after the transcription start site.
assist in activating transcription.
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.
A difference between transcription in prokaryotes and eukaryotes is the
lack of need for a primer.
presence of a transcription bubble.
addition of a poly(A) tail.
direction of transcription on the DNA template.
Identify the location of action of the spliceosome.
nuclear pore
nucleus
rough endoplasmic reticulum
cytoplasm
In which direction is mRNA synthesized by RNA polymerase?
in the 3' to 5' direction
with 5' to 3' phosphodiester linkages
in the 5' to 3' direction
It depends on whether the sense or antisense strand is transcribed.
Which of the following RNA molecules delivers amino acids to the ribosome?
rRNA
tRNA
mRNA
siRNA
Cis-acting enzymes are
self-operating enzymes.
enzymes that operate on a target molecule.
intermolecular-operating enzymes.
enzymes that operate on other enzymes.
Which of the following RNAs are directly involved in protein synthesis?
small nuclear RNA.
short interfering RNA.
ribosomal RNA.
long noncoding RNA.
The _______ strand of DNA is transcribed into mRNA.
leading
coding
lagging
template
Which of the following is a coding RNA molecule?
short interfering RNA
TERC RNA
small nucleolar RNA
messenger RNA
Which molecule contains both an amino acid acceptor stem and an anticodon?
tRNA
mRNA
rRNA
miRNA
tRNA must be _____________ before binding to the ribosome to allow for translation to occur.
charged with a codon
charged with an anticodon
charged with an amino acid
bound by ATP
The anticodon of tRNA is made up of _____________ bases.
2
3
4
5
Where would an amino acid be attached to a tRNA? (see figure to the right)
A
B
C
D
Which of the following is considered the adaptor molecule in protein synthesis?
mRNA
DNA
tRNA
rRNA
Noncanonical base pairings are observed between the third position of the codons and the first position of the anticodons. This concept is known as the
nonsense rule.
noncanonical hypothesis.
wobble hypothesis.
3:1 hypothesis.
Which of the following nucleotides in the 3'-position of an mRNA codon could base pair with a G nucleotide at the 5'-position in the tRNA anticodon?
G
U
A
T
Both prokaryotes and eukaryotes recognize _____________ as a start codon.
AUG
UAC
GUA
CAU
Eukaryotes are directed to begin scanning the mRNA for the start codon based on binding of the
Shine-Dalgarno sequence.
poly(A) tail and 5' cap.
Met-tRNAifMet.
16S rRNA.
tRNA interacts with ribosomes at one of three sites: the E site, the P site, and the _____________ site.
T
M
SD
A
Mutations that are not genetically inherited are called _______ .
germ cell
somatic
nonsense
missense
Which of the following RNAs is NOT directly involved in protein synthesis?
rRNA
RNaseP
tRNA
mRNA
Which of the following is NOT a type of processing done to convert precursor mRNA to mature mRNA in eukaryotes?
5' capping
splicing
polyadenylation
methylation
Which of the following statements is FALSE concerning telomerase?
It synthesizes an RNA primer to facilitate DNA synthesis.
It helps maintain chromosome length.
It uses an RNA template to extend DNA at the end of chromosomes.
Its activity is largely limited to undifferentiated embryonic stem cells, male germ cells, and activated
lymphocytes.
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