Which of the following variations on translation would be most
disadvantageous for a cell?
A) translating polypeptides directly
from DNA
B) using fewer kinds of tRNA
C) having only one
stop codon
D) lengthening the half-life of mRNA
E) having a
second codon (besides AUG) as a start codon
A
2) Garrod hypothesized that "inborn errors of metabolism"
such as alkaptonuria occur because
A) metabolic enzymes require
vitamin cofactors, and affected individuals have significant
nutritional deficiencies.
B) enzymes are made of DNA, and
affected individuals lack DNA polymerase.
C) many metabolic
enzymes use DNA as a cofactor, and affected individuals have mutations
that prevent their enzymes from interacting efficiently with
DNA.
D) certain metabolic reactions are carried out by ribozymes,
and affected individuals lack key splicing factors.
E) genes
dictate the production of specific enzymes, and affected individuals
have genetic defects that cause them to lack certain enzymes.
E
Garrod's information about the enzyme alteration resulting in
alkaptonuria led to further elucidation of the same pathway in humans.
Phenylketonuria (PKU) occurs when another enzyme in the pathway is
altered or missing, resulting in a failure of phenylalanine (phe) to
be metabolized to another amino acid: tyrosine. Tyrosine is an earlier
substrate in the pathway altered in alkaptonuria. How might PKU affect
the presence or absence of alkaptonuria?
A) It would have no
effect, because PKU occurs several steps away in the pathway.
B)
It would have no effect, because tyrosine is also available from the
diet.
C) Anyone with PKU must also have alkaptonuria.
D)
Anyone with PKU is born with a predisposition to later
alkaptonuria.
E) Anyone with PKU has mild symptoms of alkaptonuria.
B
4) The nitrogenous base adenine is found in all members of which
group?
A) proteins, triglycerides, and testosterone
B)
proteins, ATP, and DNA
C) ATP, RNA, and DNA
D) α glucose,
ATP, and DNA
E) proteins, carbohydrates, and ATP
C
5) A particular triplet of bases in the template strand of DNA is 5'
AGT 3'. The corresponding codon for the mRNA transcribed is
A) 3'
UCA 5'.
B) 3' UGA 5'.
C) 5' TCA 3'.
D) 3' ACU
5'.
E) either UCA or TCA, depending on wobble in the first base.
A
6) The genetic code is essentially the same for all organisms. From
this, one can logically assume which of the following?
A) A gene
from an organism can theoretically be expressed by any other
organism.
B) All organisms have experienced convergent
evolution.
C) DNA was the first genetic material.
D) The
same codons in different organisms translate into the different amino
acids.
E) Different organisms have different numbers of different
types of amino acids.
A
7) The "universal" genetic code is now known to have
exceptions. Evidence for this can be found if which of the following
is true?
A) If UGA, usually a stop codon, is found to code for an
amino acid such as tryptophan (usually coded for by UGG only).
B)
If one stop codon, such as UGA, is found to have a different effect on
translation than another stop codon, such as UAA.
C) If
prokaryotic organisms are able to translate a eukaryotic mRNA and
produce the same polypeptide.
D) If several codons are found to
translate to the same amino acid, such as serine.
E) If a single
mRNA molecule is found to translate to more than one polypeptide when
there are two or more AUG sites.
A
8) Which of the following nucleotide triplets best represents a
codon?
A) a triplet separated spatially from other
triplets
B) a triplet that has no corresponding amino
acid
C) a triplet at the opposite end of tRNA from the attachment
site of the amino acid
D) a triplet in the same reading frame as
an upstream AUG
E) a sequence in tRNA at the 3' end
D
9) Which of the following provides some evidence that RNA probably
evolved before DNA?
A) RNA polymerase uses DNA as a
template.
B) RNA polymerase makes a single-stranded
molecule.
C) RNA polymerase does not require localized unwinding
of the DNA.
D) DNA polymerase uses primer, usually made of
RNA.
E) DNA polymerase has proofreading function.
D
10) Which of the following statements best describes the termination
of transcription in prokaryotes?
A) RNA polymerase transcribes
through the polyadenylation signal, causing proteins to associate with
the transcript and cut it free from the polymerase.
B) RNA
polymerase transcribes through the terminator sequence, causing the
polymerase to separate from the DNA and release the
transcript.
C) RNA polymerase transcribes through an intron, and
the snRNPs cause the polymerase to let go of the transcript.
D)
Once transcription has initiated, RNA polymerase transcribes until it
reaches the end of the chromosome.
E) RNA polymerase transcribes
through a stop codon, causing the polymerase to stop advancing through
the gene and release the mRNA.
B
11) Which of the following does not occur in prokaryotic gene
expression, but does in eukaryotic gene expression?
A) mRNA,
tRNA, and rRNA are transcribed.
B) RNA polymerase binds to the
promoter.
C) A poly-A tail is added to the 3' end of an mRNA and
a cap is added to the 5' end.
D) Transcription can begin as soon
as translation has begun even a little.
E) RNA polymerase
requires a primer to elongate the molecule.
C
12) RNA polymerase in a prokaryote is composed of several subunits.
Most of these subunits are the same for the transcription of any gene,
but one, known as sigma, varies considerably. Which of the following
is the most probable advantage for the organism of such sigma
switching?
A) It might allow the transcription process to vary
from one cell to another.
B) It might allow the polymerase to
recognize different promoters under certain environmental
conditions.
C) It could allow the polymerase to react differently
to each stop codon.
D) It could allow ribosomal subunits to
assemble at faster rates.
E) It could alter the rate of
translation and of exon splicing.
B
13) Which of the following is a function of a poly-A signal
sequence?
A) It adds the poly-A tail to the 3' end of the
mRNA.
B) It codes for a sequence in eukaryotic transcripts that
signals enzymatic cleavage ~1035 nucleotides away.
C) It allows
the 3' end of the mRNA to attach to the ribosome.
D) It is a
sequence that codes for the hydrolysis of the RNA polymerase.
E)
It adds a 7-methylguanosine cap to the 3' end of the mRNA.
B
14) In eukaryotes there are several different types of RNA
polymerase. Which type is involved in transcription of mRNA for a
globin protein?
A) ligase
B) RNA polymerase I
C) RNA
polymerase II
D) RNA polymerase III
E) primase
C
15) Transcription in eukaryotes requires which of the following in
addition to RNA polymerase?
A) the protein product of the
promoter
B) start and stop codons
C) ribosomes and
tRNA
D) several transcription factors (TFs)
E) aminoacyl synthetase
D
16) A part of the promoter, called the TATA box, is said to be highly
conserved in evolution. Which of the following might this
illustrate?
A) The sequence evolves very rapidly.
B) The
sequence does not mutate.
C) Any mutation in the sequence is
selected against.
D) The sequence is found in many but not all
promoters.
E) The sequence is transcribed at the start of every gene.
C
17) The TATA sequence is found only several nucleotides away from the
start site of transcription. This most probably relates to which of
the following?
A) the number of hydrogen bonds between A and T in
DNA
B) the triplet nature of the codon
C) the ability of
this sequence to bind to the start site
D) the supercoiling of
the DNA near the start site
E) the 3-D shape of a DNA molecule
A
18) What is a ribozyme?
A) an enzyme that uses RNA as a
substrate
B) an RNA with enzymatic activity
C) an enzyme
that catalyzes the association between the large and small ribosomal
subunits
D) an enzyme that synthesizes RNA as part of the
transcription process
E) an enzyme that synthesizes RNA primers
during DNA replication
B
19) A transcription unit that is 8,000 nucleotides long may use 1,200
nucleotides to make a protein consisting of approximately 400 amino
acids. This is best explained by the fact that
A) many noncoding
stretches of nucleotides are present in mRNA.
B) there is
redundancy and ambiguity in the genetic code.
C) many nucleotides
are needed to code for each amino acid.
D) nucleotides break off
and are lost during the transcription process.
E) there are
termination exons near the beginning of mRNA.
A
20) During splicing, which molecular component of the spliceosome
catalyzes the excision reaction?
A) protein
B) DNA
C)
RNA
D) lipid
E) sugar
C
21) Alternative RNA splicing
A) is a mechanism for increasing
the rate of transcription.
B) can allow the production of
proteins of different sizes from a single mRNA.
C) can allow the
production of similar proteins from different RNAs.
D) increases
the rate of transcription.
E) is due to the presence or absence
of particular snRNPs.
B
22) In the structural organization of many eukaryotic genes,
individual exons may be related to which of the following?
A) the
sequence of the intron that immediately precedes each exon
B) the
number of polypeptides making up the functional protein
C) the
various domains of the polypeptide product
D) the number of
restriction enzyme cutting sites
E) the number of start sites for transcription
C
23) In an experimental situation, a student researcher inserts an
mRNA molecule into a eukaryotic cell after he has removed its 5' cap
and poly-A tail. Which of the following would you expect him to
find?
A) The mRNA could not exit the nucleus to be
translated.
B) The cell recognizes the absence of the tail and
polyadenylates the mRNA.
C) The molecule is digested by
restriction enzymes in the nucleus.
D) The molecule is digested
by exonucleases since it is no longer protected at the 5' end.
E)
The molecule attaches to a ribosome and is translated, but more slowly.
D
Use the following model of a eukaryotic transcript to answer the next
few questions.
5' UTR E₁ I₁ E₂ I₂ E₃ I₃ E₄ UTR 3'
24) Which components of the previous molecule will also be found
in mRNA in the cytosol?
A) 5' UTR I₁ I₂ I₃ UTR 3'
B) 5' E₁
E₂ E₃ E₄ 3'
C) 5' UTR E₁ E₂ E₃ E₄ UTR 3'
D) 5' I₁ I₂ I₃
3'
E) 5' E₁ I₁ E₂ I₂ E₃ I₃ E₄ 3'
C
Use the following model of a eukaryotic transcript to answer the next
few questions.
5' UTR E₁ I₁ E₂ I₂ E₃ I₃ E₄ UTR 3'
25) When the spliceosome binds to elements of this structure,
where can it attach?
A) to the exons
B) to the 5'
UTR
C) to the 3' UTR
D) to an adjacent intron and
exon
E) to the end of an intron
E
Use the following model of a eukaryotic transcript to answer the next
few questions.
5' UTR E₁ I₁ E₂ I₂ E₃ I₃ E₄ UTR 3'
26) Which of the following is a useful feature of introns for
this model?
A) They are translated into small
polypeptides.
B) They become parts of snRNPs.
C) Each intron
has enzymatic properties.
D) Introns allow exon
shuffling.
E) Introns protect exon structure.
D
Use the following model of a eukaryotic transcript to answer the next
few questions.
5' UTR E₁ I₁ E₂ I₂ E₃ I₃ E₄ UTR 3'
27) Suppose that exposure to a chemical mutagen results in a
change in the sequence that alters the 5' end of intron 1 (I₁). What
might occur?
A) loss of the gene product
B) loss of
E₁
C) premature stop to the mRNA
D) inclusion of I₁ in the
mRNA
E) exclusion of E₂
D
Use the following model of a eukaryotic transcript to answer the next
few questions.
5' UTR E₁ I₁ E₂ I₂ E₃ I₃ E₄ UTR 3'
28) Suppose that an induced mutation removes most of the 5' end
of the 5' UTR. What might result?
A) Removal of the 5' UTR has no
effect because the exons are still maintained.
B) Removal of the
5' UTR also removes the 5' cap and the mRNA will quickly
degrade.
C) The 3' UTR will duplicate and one copy will replace
the 5' end.
D) The first exon will not be read because I₁ will
now serve as the UTR.
E) Removal of the 5' UTR will result in the
strand not binding to tRNAs.
B
29) A particular triplet of bases in the coding sequence of DNA is
AAA. The anticodon on the tRNA that binds the mRNA codon is
A)
TTT.
B) UUA.
C) UUU.
D) AAA.
E) either UAA or TAA,
depending on first base wobble.
C
30) Accuracy in the translation of mRNA into the primary structure of
a polypeptide depends on specificity in the
A) binding of
ribosomes to mRNA.
B) shape of the A and P sites of
ribosomes.
C) bonding of the anticodon to the codon.
D)
attachment of amino acids to tRNAs.
E) bonding of the anticodon
to the codon and the attachment of amino acids to tRNAs
E
31) What is the function of GTP in translation?
A) GTP energizes
the formation of the initiation complex, using initiation
factors.
B) GTP hydrolyzes to provide phosphate groups for tRNA
binding.
C) GTP hydrolyzes to provide energy for making peptide
bonds.
D) GTP supplies phosphates and energy to make ATP from
ADP.
E) GTP separates the small and large subunits of the
ribosome at the stop codon.
A
32) A mutant bacterial cell has a defective aminoacyl synthetase that
attaches a lysine to tRNAs with the anticodon AAA instead of the
normal phenylalanine. The consequence of this for the cell will be
that
A) none of the proteins in the cell will contain
phenylalanine.
B) proteins in the cell will include lysine
instead of phenylalanine at amino acid positions specified by the
codon UUU.
C) the cell will compensate for the defect by
attaching phenylalanine to tRNAs with lysine-specifying
anticodons.
D) the ribosome will skip a codon every time a UUU is
encountered.
E) none of the options will occur; the cell will
recognize the error and destroy the tRNA.
B
33) There are 61 mRNA codons that specify an amino acid, but only 45
tRNAs. This is best explained by the fact that
A) some tRNAs have
anticodons that recognize four or more different codons.
B) the
rules for base pairing between the third base of a codon and tRNA are
flexible.
C) many codons are never used, so the tRNAs that
recognize them are dispensable.
D) the DNA codes for all 61 tRNAs
but some are then destroyed.
E) competitive exclusion forces some
tRNAs to be destroyed by nucleases.
B
34) Which of the following is the first event to take place in
translation in eukaryotes?
A) elongation of the
polypeptide
B) base pairing of activated methionine-tRNA to AUG
of the messenger RNA
C) binding of the larger ribosomal subunit
to smaller ribosomal subunits
D) covalent bonding between the
first two amino acids
E) the small subunit of the ribosome
recognizes and attaches to the 5' cap of mRNA
E
35) Which of the following is a function of a signal peptide?
A)
to direct an mRNA molecule into the cisternal space of the ER
B)
to bind RNA polymerase to DNA and initiate transcription
C) to
terminate translation of the messenger RNA
D) to translocate
polypeptides across the ER membrane
E) to signal the initiation
of transcription
D
36) When translating secretory or membrane proteins, ribosomes are
directed to the ER membrane by
A) a specific characteristic of
the ribosome itself, which distinguishes free ribosomes from bound
ribosomes.
B) a signal-recognition particle that brings ribosomes
to a receptor protein in the ER membrane.
C) moving through a
specialized channel of the nucleus.
D) a chemical signal given
off by the ER.
E) a signal sequence of RNA that precedes the
start codon of the message.
B
37) An experimenter has altered the 3' end of the tRNA corresponding
to the amino acid methionine in such a way as to remove the 3' AC.
Which of the following hypotheses describes the most likely
result?
A) tRNA will not form a cloverleaf.
B) The nearby
stem end will pair improperly.
C) The amino acid methionine will
not bind.
D) The anticodon will not bind with the mRNA
codon.
E) The aminoacylsynthetase will not be formed.
C
38) The process of translation, whether in prokaryotes or eukaryotes,
requires tRNAs, amino acids, ribosomal subunits, and which of the
following?
A) polypeptide factors plus ATP
B) polypeptide
factors plus GTP
C) polymerases plus GTP
D) SRP plus
chaperones
E) signal peptides plus release factor
B
39) When the ribosome reaches a stop codon on the mRNA, no
corresponding tRNA enters the A site. If the translation reaction were
to be experimentally stopped at this point, which of the following
would you be able to isolate?
A) an assembled ribosome with a
polypeptide attached to the tRNA in the P site
B) separated
ribosomal subunits, a polypeptide, and free tRNA
C) an assembled
ribosome with a separated polypeptide
D) separated ribosomal
subunits with a polypeptide attached to the tRNA
E) a cell with
fewer ribosomes
A
40) What is the function of the release factor (RF)?
A) It
separates tRNA in the A site from the growing polypeptide.
B) It
binds to the stop codon in the A site in place of a tRNA.
C) It
releases the amino acid from its tRNA to allow the amino acid to form
a peptide bond.
D) It supplies a source of energy for termination
of translation.
E) It releases the ribosome from the ER to allow
polypeptides into the cytosol.
B
41) When the function of the newly made polypeptide is to be secreted
from the cell where it has been made, what must occur?
A) It must
be translated by a ribosome that remains free of attachment to the
ER.
B) Its signal sequence must target it to the ER, from which
it goes to the Golgi.
C) It has a signal sequence that must be
cleaved off before it can enter the ER.
D) It has a signal
sequence that targets it to the cell's plasma membrane where it causes
exocytosis.
E) Its signal sequence causes it to be encased in a
vesicle as soon as it is translated.
B
42) Suppose that a mutation alters the formation of a tRNA such that
it still attaches to the same amino acid (phe) but its anticodon loop
has the sequence AAU that binds to the mRNA codon UUA (that usually
specifies leucine leu).
A) The modified tRNA will cause this mRNA
to make only nonfunctioning product.
B) The tRNA-leu will not be
able to enter the site of the ribosome to bind to the UUA.
C) One
mutated tRNA molecule will be relatively inconsequential because it
will compete with many "normal" ones.
D) The tRNA will
be so unstable that it will not participate in translation.
E)
The mutated tRNA will result in an amino acid variant in all copies of
the protein.
C
43) Why might a point mutation in DNA make a difference in the level
of protein's activity?
A) It might result in a chromosomal
translocation.
B) It might exchange one stop codon for another
stop codon.
C) It might exchange one serine codon for a different
serine codon.
D) It might substitute an amino acid in the active
site.
E) It might substitute the N-terminus of the polypeptide
for the C-terminus.
D
44) In the 1920s Muller discovered that X-rays caused mutation in
Drosophila. In a related series of experiments in the 1940s, Charlotte
Auerbach discovered that chemicals–she used nitrogen mustards–have a
similar effect. A new chemical food additive is developed by a cereal
manufacturer. Why do we test for its ability to induce
mutation?
A) We worry that it might cause mutation in cereal
grain plants.
B) We want to make sure that it does not emit
radiation.
C) We want to be sure that it increases the rate of
mutation sufficiently.
D) We want to prevent any increase in
mutation frequency.
E) We worry about its ability to cause infection.
D
45) Which of the following types of mutation, resulting in an error
in the mRNA just after the AUG start of translation, is likely to have
the most serious effect on the polypeptide product?
A) a deletion
of a codon
B) a deletion of two nucleotides
C) a
substitution of the third nucleotide in an ACC codon
D) a
substitution of the first nucleotide of a GGG codon
E) an
insertion of a codon
B
46) What is the effect of a nonsense mutation in a gene?
A) It
changes an amino acid in the encoded protein.
B) It has no effect
on the amino acid sequence of the encoded protein.
C) It
introduces a premature stop codon into the mRNA.
D) It alters the
reading frame of the mRNA.
E) It prevents introns from being excised.
C
47) A frameshift mutation could result from
A) a base insertion
only.
B) a base deletion only.
C) a base substitution
only.
D) deletion of three consecutive bases.
E) either an
insertion or a deletion of a base.
E
48) Which of the following DNA mutations is the most likely to be
damaging to the protein it specifies?
A) a base-pair
deletion
B) a codon substitution
C) a substitution in the
last base of a codon
D) a codon deletion
E) a point mutation
A
49) Which small-scale mutation would be most likely to have a
catastrophic effect on the functioning of a protein?
A) a base
substitution
B) a base deletion near the start of a gene
C)
a base deletion near the end of the coding sequence, but not in the
terminator codon
D) deletion of three bases near the start of the
coding sequence, but not in the initiator codon
E) a base
insertion near the end of the coding sequence, but not in the
terminator codon
B
50) The most commonly occurring mutation in people with cystic
fibrosis is a deletion of a single codon. This results in
A) a
base-pair substitution.
B) a nucleotide mismatch.
C) a
frameshift mutation.
D) a polypeptide missing an amino
acid.
E) a nonsense mutation.
D
51) Which of the following mutations is most likely to cause a
phenotypic change?
A) a duplication of all or most
introns
B) a large inversion whose ends are each in intergenic
regions
C) a nucleotide substitution in an exon coding for a
transmembrane domain
D) a single nucleotide deletion in an exon
coding for an active site
E) a frameshift mutation one codon away
from the 3' end of the nontemplate strand
D
52) If a protein is coded for by a single gene and this protein has
six clearly defined domains, which number of exons below is the gene
likely to have?
A) 1
B) 5
C) 8
D) 12
E) 14
C
53) Which of the following statements is true about protein synthesis
in prokaryotes?
A) Extensive RNA processing is required before
prokaryotic transcripts can be translated.
B) Translation can
begin while transcription is still in progress.
C) Prokaryotic
cells have complicated mechanisms for targeting proteins to the
appropriate cellular organelles.
D) Translation requires
antibiotic activity.
E) Unlike eukaryotes, prokaryotes require no
initiation or elongation factors.
B
54) Of the following, which is the most current description of a
gene?
A) a unit of heredity that causes formation of a phenotypic
characteristic
B) a DNA subunit that codes for a single complete
protein
C) a DNA sequence that is expressed to form a functional
product: either RNA or polypeptide
D) a DNA—RNA sequence
combination that results in an enzymatic product
E) a discrete
unit of hereditary information that consists of a sequence of amino acids
C
55) Gene expression in the domain Archaea in part resembles that of
bacteria and in part that of the domain Eukarya. In which way is it
most like the domain Eukarya?
A) Domain Archaea have numerous
transcription factors.
B) Initiation of translation is like that
of domain Eukarya.
C) There is only one RNA polymerase.
D)
Transcription termination often involves attenuation.
E)
Post-transcriptional splicing is like that of Eukarya.
A
56) Which of the following is true of transcription in domain
Archaea?
A) It is regulated in the same way as in domain
Bacteria.
B) There is only one kind of RNA polymerase.
C) It
is roughly simultaneous with translation.
D) Promoters are
identical to those in domain Eukarya.
E) It terminates in a
manner similar to bacteria.
C
57) In comparing DNA replication with RNA transcription in the same
cell, which of the following is true only of replication?
A) It
uses RNA polymerase.
B) It makes a new molecule from its 5' end
to its 3' end.
C) The process is extremely fast once it is
initiated.
D) The process occurs in the nucleus of a eukaryotic
cell.
E) The entire template molecule is represented in the product.
E
58) In order for a eukaryotic gene to be engineered into a bacterial
colony to be expressed, what must be included in addition to the
coding exons of the gene?
A) the introns
B) eukaryotic
polymerases
C) a bacterial promoter sequence
D) eukaryotic
ribosomal subunits
E) eukaryotic tRNAs
C
59) When the genome of a particular species is said to include 20,000
protein-coding regions, what does this imply?
A) There are 20,000
genes.
B) Each gene codes for one protein.
C) Any other
regions are "junk" DNA.
D) There are also genes for
RNAs other than mRNA.
E) The species is highly evolved.
D
60) According to Beadle and Tatum's hypothesis, how many genes are
necessary for this pathway?
A) 0
B) 1
C) 2
D)
3
E) It cannot be determined from the pathway.
C
61) A mutation results in a defective enzyme A. Which of the
following would be a consequence of that mutation?
A) an
accumulation of A and no production of B and C
B) an accumulation
of A and B and no production of C
C) an accumulation of B and no
production of A and C
D) an accumulation of B and C and no
production of A
E) an accumulation of C and no production of A
and B
A
62) If A, B, and C are all required for growth, a strain that is
mutant for the gene-encoding enzyme A would be able to grow on which
of the following media?
A) minimal medium
B) minimal medium
supplemented with nutrient A only
C) minimal medium supplemented
with nutrient B only
D) minimal medium supplemented with nutrient
C only
E) minimal medium supplemented with nutrients A and C
C
63) If A, B, and C are all required for growth, a strain mutant for
the gene-encoding enzyme B would be capable of growing on which of the
following media?
A) minimal medium
B) minimal medium
supplemented with A only
C) minimal medium supplemented with B
only
D) minimal medium supplemented with C only
E) minimal
medium supplemented with nutrients A and B
D
64) A possible sequence of nucleotides in the template strand of DNA
that would code for the polypeptide sequence phe-leu-ile-val would
be
A) 5' TTG-CTA-CAG-TAG 3'.
B) 3' AAC-GAC-GUC-AUA
5'.
C) 5' AUG-CTG-CAG-TAT 3'.
D) 3' AAA-AAT-ATA-ACA
5'.
E) 3' AAA-GAA-TAA-CAA 5'.
E
65) What amino acid sequence will be generated, based on the
following mRNA codon sequence?
5' AUG-UCU-UCG-UUA-UCC-UUG
3'
A) met-arg-glu-arg-glu-arg
B)
met-glu-arg-arg-glu-leu
C) met-ser-leu-ser-leu-ser
D)
met-ser-ser-leu-ser-leu
E) met-leu-phe-arg-glu-glu
D
66) A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH.
Which of the following sequences in the coding strand of the DNA could
code for this peptide?
A) 3' UUU-CCC-AAA-GGG-UUU-CCC
B) 3'
AUG-AAA-GGG-TTT-CCC-AAA-GGG
C) 5' TTT-CCC-AAA-GGG-TTT-CCC
D)
5' GGG-AAA-TTT-AAA-CCC-ACT-GGG
E) 5' ACT-TAC-CAT-AAA-CAT-TAC-UGA
C
67) Given the locally unwound double strand above, in which direction
does the RNA polymerase move?
A) 3' → 5' along the template
strand
B) 5' → 3' along the template strand
C) 3' → 5' along
the complementary strand
D) 5' → 3' along the complementary
strand
E) 5' → 3' along the double-stranded DNA
A
68) In the transcription event of the previous DNA, where would the
promoter be located?
A) at the 3' end of the newly made
RNA
B) to the right of the template strand
C) to the left of
the template strand
D) to the right of the sense strand
E)
to the left of the sense strand
B
A part of an mRNA molecule with the following sequence is being read
by a ribosome: 5' CCG-ACG 3' (mRNA). The following charged transfer
RNA molecules (with their anticodons shown in the 3' to 5' direction)
are available. Two of them can correctly match the mRNA so that a
dipeptide can form.
69) The dipeptide that will form will be
A)
cysteine-alanine.
B) proline-threonine.
C)
glycine-cysteine.
D) alanine-alanine.
E) threonine-glycine.
B
A part of an mRNA molecule with the following sequence is being read
by a ribosome: 5' CCG-ACG 3' (mRNA). The following charged transfer
RNA molecules (with their anticodons shown in the 3' to 5' direction)
are available. Two of them can correctly match the mRNA so that a
dipeptide can form.
70) The anticodon loop of the first tRNA that will complement
this mRNA is
A) 3' GGC 5'
B) 5' GGC 3'
C) 5' ACG
3'
D) 5' UGC 3'
E) 3' UGC 5'
A
71) What type of bonding is responsible for maintaining the shape of
the tRNA molecule?
A) covalent bonding between sulfur
atoms
B) ionic bonding between phosphates
C) hydrogen
bonding between base pairs
D) van der Waals interactions between
hydrogen atoms
E) peptide bonding between amino acids
C
72) The figure represents tRNA that recognizes and binds a particular
amino acid (in this instance, phenylalanine). Which codon on the mRNA
strand codes for this amino acid?
A) UGG
B) GUG
C)
GUA
D) UUC
E) CAU
D
73) The tRNA shown in the figure has its 3' end projecting beyond its
5' end. What will occur at this 3' end?
A) The codon and
anticodon complement one another.
B) The amino acid binds
covalently.
C) The excess nucleotides (ACCA) will be cleaved off
at the ribosome.
D) The small and large subunits of the ribosome
will attach to it.
E) The 5' cap of the mRNA will become
covalently bound.
B
The enzyme polynucleotide phosphorylase randomly assembles
nucleotides into a polynucleotide polymer.
74) You add polynucleotide phosphorylase to a solution of
adenosine triphosphate and guanosine triphosphate. How many artificial
mRNA 3 nucleotide codons would be possible?
A) 3
B)
4
C) 8
D) 16
E) 64
C
The enzyme polynucleotide phosphorylase randomly assembles
nucleotides into a polynucleotide polymer.
75) You add polynucleotide phosphorylase to a solution of ATP,
GTP, and UTP. How many artificial mRNA 3 nucleotide codons would be
possible?
A) 3
B) 6
C) 9
D) 27
E) 81
D
A transfer RNA (#1) attached to the amino acid lysine enters the
ribosome. The lysine binds to the growing polypeptide on the other
tRNA (#2) in the ribosome already.
76) Where does tRNA #2 move to after this bonding of lysine to
the polypeptide?
A) A site
B) P site
C) E site
D)
exit tunnel
E) directly to the cytosol
C
A transfer RNA (#1) attached to the amino acid lysine enters the
ribosome. The lysine binds to the growing polypeptide on the other
tRNA (#2) in the ribosome already.
77) Which component of the complex described enters the exit
tunnel through the large subunit of the ribosome?
A) tRNA with
attached lysine (#1)
B) tRNA with polypeptide (#2)
C) tRNA
that no longer has attached amino acid
D) newly formed
polypeptide
E) initiation and elongation factors
D
78) In eukaryotic cells, transcription cannot begin until
A) the
two DNA strands have completely separated and exposed the
promoter.
B) several transcription factors have bound to the
promoter.
C) the 5' caps are removed from the mRNA.
D) the
DNA introns are removed from the template.
E) DNA nucleases have
isolated the transcription unit.
B
79) Which of the following is not true of a codon?
A) It
consists of three nucleotides.
B) It may code for the same amino
acid as another codon.
C) It never codes for more than one amino
acid.
D) It extends from one end of a tRNA molecule.
E) It
is the basic unit of the genetic code.
D
80) The anticodon of a particular tRNA molecule is
A)
complementary to the corresponding mRNA codon.
B) complementary
to the corresponding triplet in rRNA.
C) the part of tRNA that
bonds to a specific amino acid.
D) changeable, depending on the
amino acid that attaches to the tRNA.
E) catalytic, making the
tRNA a ribozyme.
A
81) Which of the following is not true of RNA processing?
A)
Exons are cut out before mRNA leaves the nucleus.
B) Nucleotides
may be added at both ends of the RNA.
C) Ribozymes may function
in RNA splicing.
D) RNA splicing can be catalyzed by
spliceosomes.
E) A primary transcript is often much longer than
the final RNA molecule that leaves the nucleus.
A
82) Which component is not directly involved in translation?
A)
mRNA
B) DNA
C) tRNA
D) ribosomes
E) GTP
B
83) Which of the following mutations would be most likely to have a
harmful effect on an organism?
A) a nucleotide-pair
substitution
B) a deletion of three nucleotides near the middle
of a gene
C) a single nucleotide deletion in the middle of an
intron
D) a single nucleotide deletion near the end of the coding
sequence
E) a single nucleotide insertion downstream of, and
close to, the start of the coding sequence
E