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CHAPTER 15—FROM DNA TO PROTEIN
MULTIPLE CHOICE
1. Byssus is
a.
an enzyme involved in transcription.
b.
a tough, adhesive material produced by some mussels.
c.
a flexible fabric produced from some animal hairs.
d.
an enzyme involved in translation.
e.
an antibiotic produced by some yeast.
2. Every protein is assembled on ____ according to instructions that are copied from ____.
a.
mRNAs; tRNAs
b.
tRNAs; mRNAs
c.
ribosomes; mRNA
d.
tRNAs; DNA
e.
ribosomes; DNA
3. The first evidence of a connection between genes and metabolism came from studies of alkaptonuria
conducted by ____.
a.
Beadle and Tatum
b.
Griffith
c.
Watson and Crick
d.
Garrod
e.
Nirenberg and Leder
4. Evidence of a direct relationship between genes and enzymes, including development of the one gene-
one enzyme hypothesis, came from studies conducted by ____ of arginine biosynthesis in mutant
stains of Neurospora.
a.
Beadle and Tatum
b.
Griffith
c.
Watson and Crick
d.
Garrod
e.
Nirenberg and Leder
5. Consider a mutant organism that is unable to make the amino acid arginine. Knowing that the
metabolic pathway to production of arginine is ornithine → citrulline → arginosuccinate → arginine,
you test the ability of the mutant to grow in the presence of each one of these compounds, providing
just one of the compounds in each of your tests. You find that the mutant can grow in the presence of
arginosuccinate or arginine, but not in the presence of citrulline or ornithine. From this you can
conclude that the product of the gene mutated in the mutant is most directly involved in production of
____.
a.
arginine from ornithine
b.
arginosuccinate from citrulline
c.
citrulline from ornithine
d.
arginine from arginosuccinate
e.
arginosuccinate from ornithine
6. The central dogma describes the flow of information of gene expression as
a.
DNA → RNA → protein.
b.
RNA → DNA.
c.
RNA → DNA → protein.
d.
protein → DNA → RNA.
e.
DNA → protein → RNA.
7. The process of transcription refers to the use of information encoded in ____ to make ____.
a.
RNA; a DNA strand
b.
DNA; a polypeptide
c.
DNA; a complementary RNA copy
d.
a polypeptide; RNA
e.
RNA; a polypeptide
8. The process of translation refers to the use of information encoded in ____ to make ____.
a.
RNA; a DNA strand
b.
DNA; a polypeptide
c.
DNA; a complementary RNA copy
d.
a polypeptide; RNA
e.
RNA; a polypeptide
9. The RNA "alphabet" used in the genetic code has ____ letters.
a.
5
b.
64
c.
4
d.
20
e.
3
10. Except for the stop codons, the codons in the genetic code specify which of ____ amino acids to use.
a.
5
b.
64
c.
4
d.
20
e.
3
11. In both prokaryotes and eukaryotes the start codon (or initiator codon) is ____, which codes for the
amino acid ____.
a.
UGA; proline
b.
UUU; phenylalanine
c.
AAA; lysine
d.
ACG; threonine
e.
AUG; methionine
12. The degeneracy of the genetic code refers to the fact that
a.
the code has some codons that do not specify an amino acid.
b.
the code has most amino acids represented by more than one codon.
c.
the code varies considerably between different organisms.
d.
the code is commaless, with no indicators of spaces between codons.
e.
the code varies considerably between different cell types within a multicellular organism.
13. With minor exceptions, the genetic code
a.
is the same for all living organisms and viruses.
b.
is specialized so that viruses have a different code from all living organisms.
c.
differs between different organisms and viruses.
d.
is the same for all viruses and for single-celled organisms, but is more complex in
multicellular organisms.
e.
has three versions: one for viruses, one for single-celled organisms, and one for
multicellular organisms.
14. During transcription
a.
double-stranded RNA chains are produced.
b.
the entire DNA molecule is used.
c.
primase creates an RNA primer to start the RNA strand.
d.
only one of the two DNA strands acts as a template.
e.
protein is made from RNA.
15. The place where RNA polymerase first associates with DNA so that transcription can begin is called
the ____ and is located ____ of the transcribed region.
a.
promoter; upstream
b.
initiator; downstream
c.
initiator; upstream
d.
promoter; downstream
e.
intron; downstream
16. The TATA box is a key element of the ____ of most eukaryotic protein-coding genes.
a.
terminator
b.
coding region
c.
promoter
d.
transcription start point
e.
introns
17. Proteins called transcription factors are involved in ____ of transcription.
a.
both initiation and termination stages
b.
both initiation and elongation stages
c.
the termination stage
d.
the initiation stage
e.
the initiation, elongation, and termination stages
18. During the elongation stage of transcription
a.
DNA nucleotides are added to the transcript.
b.
the transcript grows in the 5'→3' direction.
c.
helicase unwinds the DNA.
d.
the double helix remains single stranded after being used as a template
e.
RNA polymerase binds the promoter region
19. Stopping transcription in prokaryotes requires
a.
generation of a stop codon.
b.
copying a terminator sequence in mRNA.
c.
splicing introns out and pasting exons together.
d.
activation of gene repressors.
e.
generation of a poly-A tail.
20. Protein-encoding genes in eukaryotes are transcribed by
a.
RNA polymerase I.
b.
RNA polymerase II.
c.
RNA polymerase III.
d.
either RNA polymerase I or III.
e.
either RNA polymerase II or III.
Use the figure above for the following question(s).
21. In the figure above, representing transcription, the item labeled "A" is
a.
reverse transcriptase.
b.
primase.
c.
the spliceosome.
d.
RNA polymerase.
e.
DNA helicase.
22. In the figure above, representing transcription, the item labeled "B" is
a.
the nontemplate strand.
b.
RNA-DNA hybrid.
c.
DNA double helix.
d.
the RNA copy.
e.
the template strand.
23. In the figure above, representing transcription, the item labeled "C" is
a.
the nontemplate strand.
b.
RNA-DNA hybrid.
c.
the template strand.
d.
DNA double helix.
e.
the RNA copy.
24. In the figure above, representing transcription, the item labeled "D" is
a.
the nontemplate strand.
b.
RNA-DNA hybrid.
c.
the template strand.
d.
DNA double helix.
e.
the RNA copy.
25. In the figure above, representing transcription, the item labeled "E" is
a.
the nontemplate strand.
b.
RNA-DNA hybrid.
c.
the template strand.
d.
DNA double helix.
e.
the RNA copy.
26. In a messenger RNA the 3' UTR refers to the region of the mRNA that is
a.
before the start codon.
b.
before the site for initiation of transcription.
c.
after the stop codon.
d.
the coding region.
e.
after the site for termination of transcription.
27. Precursor-mRNA (pre-mRNA) typically exists
a.
only in prokaryotes.
b.
in both the nucleus and cytoplasm of eukaryotes.
c.
only in the cytoplasm of eukaryotes.
d.
in both prokaryotes and eukaryotes.
e.
only in the nucleus of eukaryotes.
28. While a eukaryotic pre-mRNA is still being synthesized it is modified on its 5' end when
a.
exon shuffling mixes mRNA pieces.
b.
enzymes recognize a polyadenylation signal in the trailing RNA sequence.
c.
the RNA introns are cut out by the spliceosome.
d.
an enzyme adds a guanine-containing cap.
e.
the RNA exons are spliced together.
29. The cap on an mRNA is the site where
a.
ribosomes attach at the start of translation.
b.
the start codon is located.
c.
the process of translation ends.
d.
the stop codon is covered until needed.
e.
the mRNA is protected from attack by RNA-digesting enzymes.
30. The process of transcription in eukaryotes ends when
a.
exon shuffling mixes mRNA pieces.
b.
enzymes recognize a polyadenylation signal in the trailing RNA sequence.
c.
the RNA introns are cut out by the spliceosome.
d.
an enzyme adds a guanine-containing cap.
e.
the RNA exons are spliced together.
31. The poly(A) tail of an mRNA
a.
is where the start codon is located.
b.
covers the stop codon until it is needed.
c.
protects the mRNA from attack by RNA-digesting enzymes.
d.
is where ribosomes attach at the start of translation.
e.
is where the process of translation ends.
32. After processing of pre-mRNAs, the regions that are retained in finished mRNAs are called ____.
a.
UTRs
b.
snRNPs
c.
exons
d.
domains
e.
introns
33. The process of removing introns from mRNA and putting the remaining exons together occurs in a
complex called the ____.
a.
ribosome
b.
anticodon
c.
lariat
d.
polysome
e.
spliceosome
34. Small ribonucleoprotein particles (snRNPs) are involved in ____.
a.
mRNA splicing
b.
initiation of transcription
c.
aminoacylation of tRNA
d.
initiation of translation
e.
termination of translation
35. In the process of mRNA splicing, the lariat structure is
a.
the splicing complex.
b.
the region where two exons are pasted together.
c.
the enzyme that cuts the pre-mRNA.
d.
the released intron.
e.
the region where two introns are pasted together.
36. Human cells produce perhaps as many as 100,000 different proteins, and yet the human genome has
only about 20,000 genes. This is best explained by
a.
aminoacylation.
b.
exon shuffling.
c.
the wobble hypothesis.
d.
degeneracy.
e.
alternative splicing.
37. Smooth muscle and striated muscle have distinct mRNA forms for some genes due to ____.
a.
aminoacylation
b.
alternative splicing
c.
polyadenylation
d.
degeneracy
e.
exon shuffling
38. The human protein TPA has domains that are genetically similar to domains from other proteins,
including epidermal growth factor and fibronectin. This is best explained by ____.
a.
alternative splicing
b.
degeneracy
c.
exon shuffling
d.
the wobble hypothesis
e.
aminoacylation
39. The process of translation of nuclear protein-coding genes in eukaryotic cells occurs in the ____.
a.
cytoplasm
b.
Golgi apparatus
c.
nucleolus
d.
nucleus
e.
mitochondria
40. This type of RNA is typically found as a strand about 75−90 bases long that folds into a structure with
four double-helical segments.
a.
snRNA
b.
pre-mRNA
c.
rRNA
d.
tRNA
e.
mRNA
41. The structure in the figure above represents a molecule of ____.
a.
pre-mRNA
b.
tRNA
c.
snRNA
d.
mRNA
e.
rRNA
42. The region in a tRNA that bonds with mRNA during translation is the ____.
a.
anticodon
b.
aminoacylation site
c.
TATA box
d.
cloverleaf
e.
reading frame
43. The ability of some tRNAs to pair with different codons is described according to ____ as being due to
imprecise base pairing with the third base in the codon.
a.
alternative splicing
b.
degeneracy
c.
exon shuffling
d.
the wobble hypothesis
e.
aminoacylation
44. If the anticodon sequence of a(n) ____ is correct, a special enzyme will bind to it and "charge" it by
adding the correct amino acid to its 3' end.
a.
pre-mRNA
b.
tRNA
c.
snRNA
d.
mRNA
e.
rRNA
45. The process of adding the correct amino acid onto a tRNA molecule is catalyzed by ____.
a.
the tRNA itself
b.
RNA polymerase
c.
an mRNA
d.
the ribosome
e.
an aminoacyl-tRNA synthetase
46. The formation of peptide bonds during translation is catalyzed by peptidyl transferase, an enzyme that
is
a.
a protein in the small ribosomal subunit.
b.
part of an rRNA in the small ribosomal subunit.
c.
part of an rRNA in the large ribosomal subunit.
d.
a protein in the large ribosomal subunit.
e.
carried to the growing peptide chain by a tRNA
47. The site of translation in all living cells is the ribosome, which is
a.
made of large and small subunits in both prokaryotes and eukaryotes.
b.
made of large and small subunits in eukaryotes, but is a single unit in prokaryotes.
c.
a single unit in both prokaryotes and eukaryotes.
d.
made of large and small subunits in prokaryotes but is a single unit in eukaryotes.
e.
larger in prokaryotes than eukaryotes
48. The antibiotics streptomycin and erythromycin function by inhibiting the function of ____ in
prokaryotes but not eukaryotes.
a.
RNA polymerases
b.
aminoacyl-tRNA synthetases
c.
spliceosomes
d.
DNA polymerases
e.
ribosomes
49. At the start of translation the initiator tRNA is base paired with the start codon at ____ in the
ribosome.
a.
the A site (aminoacyl site)
b.
first the A site (aminoacyl site) and then the E site (exit site)
c.
the P site (peptidyl site)
d.
first the A site (aminoacyl site) and then the P site (peptidyl site)
e.
the E site (exit site)
50. Which of the regions of the ribosome accepts charged tRNA molecules during the elongation phase of
translation?
a.
the A site (aminoacyl site)
b.
first the A site (aminoacyl site) and then the E site (exit site)
c.
the P site (peptidyl site)
d.
first the A site (aminoacyl site) and then the P site (peptidyl site)
e.
the E site (exit site)
51. Which of these events in translation in eukaryotes does NOT directly involve hydrolysis of GTP?
a.
release of initiation factors
b.
binding of a proper aminoacyl tRNA with a codon at the A site
c.
formation of the peptide bond
d.
translocation of the ribosome along the mRNA
e.
all of these events directly involve GTP hydrolysis
52. Initiation factors are ____ that assist in the initiation of transcription.
a.
mRNAs
b.
proteins
c.
tRNAs
d.
amino acids
e.
snRNPs
53. The ribosome binding site is located ____ and is where ____.
a.
at the start codon; the large ribosome subunit binds the mRNA-tRNA complex in
prokaryotes
b.
just upstream of the start codon; the large ribosome subunit binds the mRNA in eukaryotes
c.
on initiator tRNA; the large ribosome subunit binds the mRNA-tRNA complex in
eukaryotes
d.
on aminoacyl-tRNA; the large ribosome subunit binds the tRNA in prokaryotes
e.
just upstream of the start codon; the small ribosome subunit binds the mRNA in
prokaryotes
54. In translation the reading frame is established by
a.
removal of the cap from mRNA.
b.
pairing of initiator tRNA with the start codon.
c.
the first base in the mRNA molecule.
d.
the first tRNA to bind a codon at the A site.
e.
aligning a stop codon with the A site.
55. Which of the regions of the ribosome accepts charged tRNA molecules during the elongation phase of
translation?
a.
the A site (aminoacyl site)
b.
either the A site (aminoacyl site) or the E site (exit site)
c.
the P site (peptidyl site)
d.
either the P site (peptidyl site) or the E site (exit site)
e.
the E site (exit site)
56. In translation the joining of amino acids is catalyzed by the enzyme ____.
a.
RNA polymerase
b.
reverse transcriptase
c.
peptidyl transferase
d.
polyadenylase
e.
aminoacyl-tRNA synthetase
57. Relative to the mRNA, which of the following moves during translocation?
a.
attached tRNAs and the ribosome
b.
attached tRNAs and the polypeptide chain
c.
the ribosome only
d.
the ribosome and the polypeptide chain
e.
the polypeptide chain only
58. The energy for translocation during translation comes from
a.
formation of the peptide bond.
b.
breaking of bonds between tRNA and mRNA.
c.
breaking of bonds between mRNA and the ribosome.
d.
removal of a tRNA from the E site.
e.
hydrolysis of GTP.
59. During translation, tRNAs bond to mRNAs using
a.
ionic bonds.
b.
van der Waals forces.
c.
nonpolar covalent bonds.
d.
hydrogen bonds.
e.
polar covalent bonds.
