Nucleic Acids/DNA and RNA/Other Things Flashcards
(174 cards)
1
Q
- Which of the following best describes electrophoretic gels used for DNA?
a. Most separations are done horizontally, while sequencing gels are typically run vertically.
b. Most separations are done vertically, while sequencing gels are typically run horizontally.
c. Most electrophoretic gels are run horizontally, whether for separation or sequencing.
d. Most electrophoretic gels are run vertically, whether for separation or sequencing.
A
a. Most separations are done horizontally, while sequencing gels are typically run vertically.
2
Q
- Migration of DNA during electrophoresis is based
a. mostly on the size of the molecule, since the ratio of charge to mass is approximately the same, no matter how large the DNA is.
b. mostly on the charge of the molecule, since the ratio of charge to mass is approximately the same, no matter how large the DNA is.
c. mostly on the charge-to-mass ratio since this can vary greatly among pieces of DNA.
d. on parameters not understood well.
A
a. mostly on the size of the molecule, since the ratio of charge to mass is approximately the same, no matter how large the DNA is.
3
Q
- The application of gel electrophoresis (PAGE) in DNA sequencing
a. is nonexistent because DNA fragments differ widely in charge.
b. depends on separation of similar charge/mass ratio on the basis of size.
c. depends on separation of identical size on the basis of charge/mass ratio.
d. is nonexistent because DNA fragments have no net charge.
A
b. depends on separation of similar charge/mass ratio on the basis of size.
4
Q
- Which of the following parameters affects the distance DNA molecules migrate during electrophoresis, at pH = 8?
a. The mass of the DNA
b. The total ionic charge on the DNA molecule
c. The fact that each nucleotide contributes one negative charge at this pH.
d. The concentration of agarose or polyacrylamide in the gel.
e. All of these features control the distance the DNA migrates.
A
e.
All of these features control the distance the DNA migrates.
5
Q
- Fluorescence works because the fluorescent molecule
a. absorbs light at one wavelength and emits light at a longer wavelength.
b. absorbs light at one wavelength and emits light at a shorter wavelength.
c. absorbs light at one wavelength and emits light at the same wavelength.
d. absorbs light at many wavelengths and emits light at many wavelengths.
A
a.
absorbs light at one wavelength and emits light at a longer wavelength.
6
Q
- When fluorescence detection methods are used in biotechnology they
a. have limitations due to low sensitivity
b. can be used for only one substance at a time
c. are not used in DNA sequencing
d. do not present the hazards associated with radioactivity
A
d.
do not present the hazards associated with radioactivity
7
Q
- A highly useful method for determining the presence of hydrolyzed fragments of DNA separated by electrophoresis is
a. autoradiography.
b. x-ray crystallography.
c. analytical ultracentrifugation.
d. all of the above
A
a.
autoradiography.
8
Q
- Fluorescent techniques can detect concentrations as low as
a. molar (101 M).
b. micromolar (10−6 M).
c. picomolar (10−12 M).
d. attamolar (10−18 M).
A
c.
picomolar (10−12 M).
9
Q
- Which of the following are methods used to determine where the DNA bands are located on an electrophoresis gel?
a. Radioactivity
b. Fluorescence
c. Dyes which bind to DNA
d. Luminescence
e. All of these can visualize the DNA
A
e.
All of these can visualize the DNA
10
Q
- Fluorescence and other luminescent methods of visualizing bands offer these advantages over methods dependent on radioactivity.
a. They can detect smaller amounts of material (they are more sensitive).
b. Fluorescent molecules like ethidium bromide offer no health hazard, while radioisotopes do.
c. Special licenses are required to work with radioisotopes.
d. These methods are both more sensitive and require no special license.
e. All of these are advantages.
A
d.
These methods are both more sensitive and require no special license.
11
Q
- SyBr green and SyBr gold were developed because
a. ethidium bromide is not sensitive enough for modern research
b. they allow faster electrophoretic separations of DNA
c. they fluoresce with RNA as well as DNA, while ethidium bromide does not
d. ethidium bromide is carcinogenic
A
d.
ethidium bromide is carcinogenic
12
Q
- Restriction enzymes are especially useful for genetic recombination work for all of the following reasons, except:
a. They cut DNA in the middle of specific sequences.
b. They cut DNA independent of the source of the DNA.
c. They often generate single stranded tails or “sticky ends”.
d. There are a large variety of them commercially available.
e. All of these traits make restriction enzymes useful.
A
e.
All of these traits make restriction enzymes useful.
13
Q
- The “natural” function of restriction endonucleases is to
a.
protect bacterial cells from invasion by viruses (bacteriophages).
b.
help bacteriophages infect cells.
c.
regulate gene expression from specific promoters.
d.
remove chromatin from histones.
A
a.
protect bacterial cells from invasion by viruses (bacteriophages).
14
Q
- Which of the following statements concerning restriction endonucleases is true?
a.
They attack RNA, not DNA.
b.
They can produce “sticky ends”.
c.
They attack single-stranded sequences only.
d.
They do not display sequence specificity in their site of attack.
A
b.
They can produce “sticky ends”.
15
Q
- A palindrome is
a.
a DNA sequence that contains only one kind of base
b.
a DNA sequence that contains only two kinds of bases
c.
a sequence that reads the same from left to right or from right to left
d.
none of the above
A
c.
a sequence that reads the same from left to right or from right to left
16
Q
- An isoschizomer is a(n)
a.
a DNA sequence that is identical to one in a different organsim
b.
a DNA sequence from a virus that mimics a sequence in bacteria
c.
enzyme that cuts DNA from the 3’ end
d.
a restriction enzyme that has the same sequence specificity as another restriction enzyme from a different organism
e.
none of these is correct
A
d.
a restriction enzyme that has the same sequence specificity as another restriction enzyme from a different organism
17
Q
- A single clone of interest can be distinguished from others in a mixture of clones by
a.
testing the clones for antibiotic resistance.
b.
mobility of the clones in gel electrophoresis.
c.
a specific probe, usually a labeled complementary DNA.
d.
resistance to damage by ultraviolet light.
A
c.
a specific probe, usually a labeled complementary DNA.
18
Q
- Enzymes that seal nicks in DNA are called
a.
restriction enzymes.
b.
bacteriophages.
c.
ligases.
d.
exonucleases.
A
c.
ligases.
19
Q
- A plasmid is
a.
a virus that infects bacteria.
b.
a piece of DNA derived from two or more sources.
c.
a small circular DNA that is not part of a bacterial chromosome.
d.
an artificially created cytoplasm.
A
c.
a small circular DNA that is not part of a bacterial chromosome.
20
Q
- The following steps are all involved in genetic recombination:
1.
Screening for cells that contain the recombined gene.
2.
Cutting the vector with restriction enzyme.
3.
Mixing the gene of interest with the vector.
4.
Isolating the gene of interest from its original source.
5.
Ligating the gene of interest and the vector together.
The following sequence of these five steps would be typical:
a.
1 → 2 → 3 → 4 → 5
b.
2 → 3 → 5 → 1 → 4
c.
5 → 4 → 3 → 2 → 1
d.
4 → 2 → 3 → 5 → 1
e.
2 → 3 → 5 → 4 → 1
A
d.
4 → 2 → 3 → 5 → 1
21
Q
- Which of the following are methods by which bacteria can be induced to take up recombinant DNA molecules?
a.
Heat shock.
b.
DNA “guns” which spray the DNA at very high speeds.
c.
Electroporation
d.
Phage or virus infection.
e.
All of these are used to transform bacteria.
A
e.
All of these are used to transform bacteria.
22
Q
- Multi-cloning sites (“poly-linkers”) in most commercially available plasmids offer all the following advantages over the earlier plasmids used in genetic recombination except:
a.
They can be used with a wide variety of restriction enzymes.
b.
They assure that only the desired DNA will be inserted into the plasmid.
c.
They enable easy control of the direction of insertion of the gene of interest.
d.
They are usually adjacent to any necessary promoters for gene expression.
e.
All of these are advantages.
A
b.
They assure that only the desired DNA will be inserted into the plasmid.
23
Q
- In recombinant DNA technology
a.
vectors are used as carriers for recombinant genes.
b.
it is possible to insert eukaryotic genes into prokaryotic DNA.
c.
foreign DNA is frequently inserted into a bacterial plasmid.
d.
all of these
A
d.
all of these
24
Q
- The presence of bacterial or viral clones is detected experimentally by
a.
the presence of colonies or plaques on a suitably prepared Petri dish.
b.
gel electrophoresis.
c.
analytical ultracentrifugation.
d.
x-ray crystallography.
A
a.
the presence of colonies or plaques on a suitably prepared Petri dish.
25
27. Suitable vectors for cloning of recombinant DNA can be
a.
bacteriophages.
b.
bacterial plasmids.
c.
both of these.
d.
neither of these.
c.
both of these.
26
28. Which of the following is not required in order for a plasmid to be used in genetic recombination?
a.
An "ori" site.
b.
A gene to allow for easy screening an isolation of cells which contain the plasmid.
c.
A poly-cloning site or multi-cloning site for gene insertion.
d.
At least one site for a restriction enzyme to cut.
e.
All of these are essential in a plasmid for DNA recombination.
c.
A poly-cloning site or multi-cloning site for gene insertion.
27
29. Cells that contain a "blue/white screening" plasmid that has an added gene are recognized by the method:
a.
Ability to grow on ampicillin.
b.
Inability to grow on ampicillin.
c.
The colonies have a blue color.
d.
The colonies lack a blue color.
e.
More than one of these choices indicates that the plasmid contains recombined DNA.
d.
The colonies lack a blue color.
28
30. During the simplest type of genetic recombination, there is a ____ chance that the gene will be inserted in the correct direction.
a.
10%
b.
25%
c.
50%
d.
75%
e.
100%
c.
50%
29
32. Refer to Exhibit 13A. If a recombinant plasmid were obtained inserting DNA into the BamHI site, the recombinant plasmid would lack which of the following properties?
a.
It would replicate autonomously.
b.
It would be resistant to the antibiotic tetracycline.
c.
It would be resistant to the antibiotic ampicillin.
d.
It would possess at least two promoter sites.
b.
It would be resistant to the antibiotic tetracycline.
30
33. Refer to Exhibit 13A. If a recombinant plasmid were obtained by inserting DNA into the EcoRV site, and the protein corresponding to the recombinant gene were expressed, which of the following statements would be false?
a.
The protein will probably contain some extra amino acids on its N-terminal.
b.
The plasmid will be resistant to ampicillin.
c.
The plasmid will not be able to replicate autonomously.
d.
The protein is not likely to be biologically active without some further treatment.
e.
The question cannot be answered, since it is unlikely that the protein will be expressed at all, because there is no promoter for mRNA synthesis.
c.
The plasmid will not be able to replicate autonomously.
31
34. Refer to Exhibit 13A. If a recombinant plasmid were obtained inserting DNA into the AflIII site, the recombinant plasmid would lack which of the following properties?
a.
It can replicate autonomously.
b.
It will be resistant to the antibiotic tetracycline.
c.
It will be resistant to the antibiotic ampicillin.
d.
It will possess at lest two promoter sites.
e.
All of these are true for the recombined plasmid.
a.
It can replicate autonomously.
32
35. Refer to Exhibit 13A. If a recombinant plasmid was obtained inserting DNA into the BamHI site, screening for the recombinant plasmid can be done by the following technique.
a.
Plate on nutrient agar plates that contain ampicillin.
b.
Plate on nutrient agar plates that contain tetracycline.
c.
Plate on nutrient agar plates that contain both ampicillin and tetracycline.
d.
Plate on nutrient agar plates that contain ampicillin, followed by replica plating on tetracycline.
e.
Plate on nutrient agar plates that contain tetracycline, followed by replica plating on ampicillin.
d.
Plate on nutrient agar plates that contain ampicillin, followed by replica plating on tetracycline.
33
37. Refer to Exhibit 13A. If the plasmid were completely digested with the two restriction enzymes BamHI and HgiEII, the resulting fragments would be this large:
a.
1920, 1305, 761, and 377 base pairs long.
b.
1920, 1682 and 761 base pairs long.
c.
1920, 1680 and 761 base pairs long.
d.
3056, 2295 and 375 base pairs long.
e.
The sizes cannot be determined from the data given.
b.
1920, 1682 and 761 base pairs long.
34
39. A multiple cloning site is also known as:
a.
a polylinker
b.
an origin of replication
c.
a restriction enzyme site
d.
a selectable marker
a.
a polylinker
35
40. Refer to Exhibit 13D. Which restriction site is best for inserting a DNA fragment for analysis?
a.
BamHI
b.
EcoRI
c.
HindIII
d.
They're all equally good.
c.
HindIII
36
42. Refer to Exhibit 13D. Neglecting any discussion of whether it's a good or bad choice, I attempt to insert a gene fragment into the HindIII site and transform bacteria with the plasmid. How can I tell which transformants have the insert?
a.
The bacteria will not be able to grow in the presence of ampicillin, and they will be blue.
b.
The bacteria will not be able to grow in the presence of ampicillin, and they will be white.
c.
The bacteria will be able to grow in the presence of ampicillin, and they will be blue.
d.
The bacteria will be able to grow in the presence of ampicillin, and they will be white.
d.
The bacteria will be able to grow in the presence of ampicillin, and they will be white.
37
43. When viruses are used as vectors in gene therapy
a.
they are not to transform cells taken from the patient's body to give back to the patient
b.
they can cause unexpected difficulties
c.
both of the above
d.
neither of the above
b.
they can cause unexpected difficulties
38
44. Genetic engineering which recombines DNA from different species is
a.
a molecular extension of traditional cross-breeding methods.
b.
only possible with plants.
c.
only possible with animals.
d.
only possible with bacteria.
a.
a molecular extension of traditional cross-breeding methods.
39
45. Which of the following was not a technique researchers used to try to improve shelf life of tomatoes with genetic engineering?
a.
Insertion of a second polygalactouronase gene
b.
Using an antisense gene
c.
Inhibition of the production of ethylene
d.
Storage in a 40 degree Celcius compartment
d.
Storage in a 40 degree Celcius compartment
40
46. How is human insulin produced by genetically engineered bacteria?
a.
DNA that codes for each of the two polypeptide chains is introduced into two different populations of bacteria
b.
DNA that codes for the insulin precursor is introduced into bacterial plasmids
c.
DNA that codes for both the polypeptide chains is introduced into a single population of bacteria
d.
This procedure cannot be done.
a.
DNA that codes for each of the two polypeptide chains is introduced into two different populations of bacteria
41
48. How does an expression vector differ from a regular cloning vector?
a.
An expression vector does not have an origin of replication.
b.
An expression vector is always a linear molecule, while a cloning vector may be circular.
c.
An expression vector has the ability to have the inserted DNA be transcribed.
d.
An expression vector must be of viral origin, so that it can infect a cell naturally.
c.
An expression vector has the ability to have the inserted DNA be transcribed.
42
49. Which of the following plants have been genetically modified?
a.
Soy beans
b.
Corn.
c.
Cotton
d.
Tomatoes
e.
All of these plants have been genetically modified.
e.
All of these plants have been genetically modified.
43
50. In gene therapy
a.
restriction enzymes are introduced into cells to cleave specific genes.
b.
new origins of replication are added to cells to promote cell division.
c.
cells of specific tissues are altered in a way that alleviates the effects of a disease.
d.
traits are altered so that descendents of those treated will inherit those new traits.
c.
cells of specific tissues are altered in a way that alleviates the effects of a disease.
44
54. Which of the following proteins has been successfully produced through genetic recombination?
a.
insulin
b.
human growth hormone
c.
tissue plasminogen activator
d.
erythropoietin
e.
All of the above proteins have been produced successfully.
e.
All of the above proteins have been produced successfully.
45
55. Which of the following is not a potential benefit of creating a fusion protein in genetic engineering?
a.
If a signal peptide is included, the protein may be excreted from the cell, making it easier to isolate.
b.
If certain sequences are produced (for example, a histidine oligopeptide), the protein may be isolated by affinity chromatography.
c.
The protein is less likely to be antigenic.
d.
Both signal peptides and histidine oligomers are useful.
e.
All of these reasons are benefits to the protein product.
c.
The protein is less likely to be antigenic.
46
56. Genetic engineering
a.
is being used to produce improved crop plants.
b.
may provide therapy for diseases of genetic origin.
c.
neither of these
d.
both of these
d.
both of these
47
57. Which of the following statements about plants which contain the recombinant form of the gene from Bacillus thuringiensis (Bt gene), is true?
a.
These plants have a natural resistance to caterpillars.
b.
The gene is expressed in all the plant tissues.
c.
Since the gene is expressed in the pollen of the plant, there is concern about the gene harming beneficial insects.
d.
It is likely that some insects will mutate to become resistant to the Bt gene product.
e.
All of these statements are true.
e.
All of these statements are true.
48
58. Which of the following conditions is an example of how genetic engineering is currently used to increase food production?
a.
Genetically modified plants have been developed that are resistant to herbicides.
b.
Genetically modified plants have been developed which contain a gene that confers a natural resistance to certain insects.
c.
Hormones are given to cows to increase milk production.
d.
Genetically modified plants have been developed which are resistant to frost.
e.
All of these are examples of genetic engineering in agriculture.
e.
All of these are examples of genetic engineering in agriculture.
49
59. Modern genetic engineering allows the following manipulation, which was not available using traditional breeding methods:
a.
It is now possible to cross different strains or varieties of the same species.
b.
It is now possible to include genes from different species, or even different kingdoms in the same organism.
c.
It is now possible to produce organisms which are more hardy or which produce bigger or more fruit.
d.
The premise of the question is invalid, since there really is no substantive difference between modern genetic engineering and traditional breeding methods.
e.
All of these were possible using traditional breeding methods.
b.
It is now possible to include genes from different species, or even different kingdoms in the same organism.
50
60. Which of the following conditions is not a requirement to assure production of a protein when a plasmid is being designed to express a eukaryotic protein in a bacterium?
a.
Introns must be deleted from the gene.
b.
The cloning site must include an RNA polymerase promoter.
c.
The mRNA product must contain a ribosome-binding site.
d.
Differences in the genetic code between eukaryotes and prokaryotes must be accommodated.
e.
All of these conditions must be met.
d.
Differences in the genetic code between eukaryotes and prokaryotes must be accommodated.
51
61. Which of the following proteins are produced by recombinant DNA technology but have had their purposes subverted for improving athletic perforrmance?
a.
Erythropoietin
b.
Human Growth Hormone
c.
Insulin
d.
Enterokinase
e.
Erythropoietin and Human Growth Hormone
f.
All of these
e.
Erythropoietin and Human Growth Hormone
52
64. Epogen is
a.
the trade name of recombinant erythropoietin
b.
a recombinant protein used to help people that need kidney dialisys
c.
a recombinanat protein often used illegally to boost athletic performance
d.
all of these
d.
all of these
53
65. Sometimes DNA probes are used to prove that a gene has been incorporated into a eukaryotic genome. The following are all steps used in such a procedure, except:
a.
Digestion of the cellular DNA to break it into manageable sizes.
b.
Separation of the fragments by gel electrophoresis.
c.
Hybridization of a nucleic acid strand complementary to the gene of interest.
d.
Elution of the hybridized DNA from the gel for analysis.
e.
All of these steps are necessary in probing for the presence of a gene.
d.
Elution of the hybridized DNA from the gel for analysis.
54
66. The "c" in cDNA stands for this word:
a.
Complete.
b.
Circular.
c.
Complementary.
d.
Chromosomal.
e.
Confusing.
c.
Complementary.
55
67. An expression library contains genes corresponding to all of the following, except:
a.
The mRNA made in a specific cell type.
b.
The genes for all the proteins found in an organism.
c.
The mRNA made in a specific tissue.
d.
The genes expressed during a particular developmental stage of the organism.
e.
An expression library could be any of these choices.
e.
An expression library could be any of these choices.
56
68. A DNA library consists of
a.
all the DNA of an organism divided up and cloned in suitable vectors
b.
an alphabetical list of all the genes in an organism
c.
a set of reference books on genetics
d.
none of the above
a.
all the DNA of an organism divided up and cloned in suitable vectors
57
69. If mRNA is converted to DNA, digested with restriction enzymes, and cloned into suitable vectors, the resultant library is called a:
a.
DNA library
b.
cDNA library
c.
mRNA library
d.
none of these
b.
cDNA library
58
70. Expression libraries are most often made from
a.
the mRNA found with a given cell or tissue.
b.
the genome of a given cell or tissue.
c.
the promoters of a given cell or tissue.
d.
the DNA of a single chromosome from cell type or tissue.
a.
the mRNA found with a given cell or tissue.
59
71. Which of the following is not a purpose of using nitrocellulose during screening of a DNA library?
a.
To transfer colonies to from the agar plates
b.
To allow hybridization with a DNA probe
c.
To duplicate the colonies for later retrieval of the DNA of interest
d.
To grow bacterial colonies
d.
To grow bacterial colonies
60
72. In the polymerase chain reaction
a.
it is possible to amplify small amounts of DNA without cloning.
b.
conditions must be carefully controlled to prevent explosions.
c.
reaction mixtures must be kept chilled at all times.
d.
all of these
e.
none of these
a.
it is possible to amplify small amounts of DNA without cloning.
61
73. The polymerase chain reaction requires
a.
primers complementary to the ends of the sequence to be amplified
b.
careful temperature control
c.
both of these
d.
neither of these
c.
both of these
62
74. The following item was the most important one for the development of PCR as a commercially successful and widely-used procedure:
a.
Taq DNA Polymerase.
b.
Heat-resistant DNA.
c.
Heat-resistant primers for DNA synthesis.
d.
Robotic machines to run the PCR® procedure.
e.
Heat-resistant nucleoside triphosphate substrates.
a.
Taq DNA Polymerase.
63
75. Advantages of the Polymerase Chain Reaction include all of these, except:
a.
The reaction is specific for certain sequences in the DNA.
b.
Only small amounts of template are needed.
c.
Results can be obtained with DNA that is old or partially degraded.
d.
All the products from a specific part of the DNA will be the same size.
e.
All of these are advantages of PCR®.
e.
All of these are advantages of PCR®.
64
76. The best primers for the PCR reaction have the following feature:
a.
They have a high G−C content.
b.
They have a high A−T content.
c.
They should be palindromic.
d.
The AT/GC ratio does not matter.
e.
They should anneal rapidly, before the larger DNA strands reanneal.
e.
They should anneal rapidly, before the larger DNA strands reanneal.
65
77. Which of the following is a unique feature of qPCR compared to the original PCR?
a.
qPCR uses a DNA polymerase from a heat stable source
b.
qPCR requires a primer
c.
qPCR allows the reaction to run until all of the primers have been exhausted
d.
In qPCR, the speed with which the DNA is produced is used to estimate how much of the original template was in the reaction vessel
d.
In qPCR, the speed with which the DNA is produced is used to estimate how much of the original template was in the reaction vessel
66
79. The RFLP technique
a.
is of most use with prokaryotic DNA
b.
is of no use on DNA that contains introns
c.
is used on the DNA of organisms that have two sets of chromosomes
d.
provides fewer genetic markers than classical genetic techniques
c.
is used on the DNA of organisms that have two sets of chromosomes
67
80. The usefulness of blotting techniques in molecular biology is that
a.
spills of hazardous chemicals are minimized
b.
only the substance of interest is transferred to a nitrocellulose disk
c.
it directly gives rise to a genetic map
d.
transferred material is in the same relative position on the disk as on the original sample
d.
transferred material is in the same relative position on the disk as on the original sample
68
82. Which of the following is true?
a.
When DNA evidence is used in crime cases, it is easier to prove that a person is guilty than that they are innocent.
b.
When DNA evidence is used in a paternity case, it is easier to prove that a person is the father rather than the person is not the fathere
c.
DNA evidence is easier to use to exclude a putative match than to include it
d.
none of these is true
c.
DNA evidence is easier to use to exclude a putative match than to include it
69
83. The same gene on two different paired chromosomes in eukaryotes are called
a.
vectors.
b.
homologies.
c.
alleles.
d.
fingerprints.
c.
alleles.
70
84. Forensic uses of DNA to identify victims or criminals exploit the following trait in DNA:
a.
Differences in sizes of DNA fragments (RFLPs).
b.
Footprinting.
c.
Site directed mutations.
d.
DNA with proteins bound moves slower in gel electrophoresis.
e.
More than one of these is important in using DNA for forensic identification.
a.
Differences in sizes of DNA fragments (RFLPs).
71
85. When fluorescent markers are used for DNA sequencing:
a.
the DNA separations are faster
b.
four different reaction mixtures must be used
c.
computer analysis can help in the detection of sequencing analysis at a faster rate
d.
none of these
c.
computer analysis can help in the detection of sequencing analysis at a faster rate
72
86. A feature of the Sanger-Coulson method for DNA sequencing is
a.
chemical modification of all bases
b.
no need to use gel electrophoresis
c.
use of triple-helical DNA
d.
direct "reading" of the sequence of bases
d.
direct "reading" of the sequence of bases
73
87. Each band in a lane of a Sanger Coulson sequencing gel represents
a.
random cutting of DNA
b.
a single nucleotide that ran that far on a gel
c.
a piece of DNA that ended in a specific base
d.
none of these
c.
a piece of DNA that ended in a specific base
74
88. In DNA sequencing, fragments to be analyzed are produced by
a.
acid hydrolysis
b.
base hydrolysis
c.
selective interruption of DNA synthesis
d.
exposure to ^32 P
c.
selective interruption of DNA synthesis
75
89. RNA is sequenced by
a.
exactly the same methods as those used for proteins
b.
exactly the same methods as those used for DNA
c.
sequencing the complementary DNA produced by the reverse transcriptase reaction
d.
a combination of analytical ultracentrifugation and ultraviolet spectroscopy
c.
sequencing the complementary DNA produced by the reverse transcriptase reaction
76
90. A proteome is
a.
a protein-based vector.
b.
a three-dimensional protein structure.
c.
a collection of all the proteins produced in a given cell or tissue.
d.
an improperly digested protein responsible for certain diseases such as "mad cow" disease.
c.
a collection of all the proteins produced in a given cell or tissue.
77
92. A transcriptome is
a.
an mRNA-based vector.
b.
three-dimensional mRNA structure.
c.
a collection of all the genes being transcribed in a given cell or tissue at a given time.
d.
the mRNA transcribed to produce a fusion protein.
c.
a collection of all the genes being transcribed in a given cell or tissue at a given time.
78
93. In a metabolic study using microarrays, a yellow dot represents the location of DNA on the microarray:
a.
for which mRNA was produced in both the control and the test case
b.
for which no mRNA was produced
c.
for which only the control case produced mRNA
d.
for which only the test case produced mRNA
a.
for which mRNA was produced in both the control and the test case
79
94. Determining disease states using protein arrays may be limited by
a.
the inability to find proteins to test
b.
the inability to put large numbers of samples on a protein chip
c.
the lack of a suitable antibody to test with
d.
the inability to visualize results
c.
the lack of a suitable antibody to test with
80
95. Which of the following types of polymerase chain reactions (PCR) is used to determine the amount of target DNA initially present in a cell?
a.
Nested PCR
b.
Asymmetric PCR
c.
Quantitative PCR
d.
Multiplex PCR
c.
Quantitative PCR
81
97. Which of the following components is responsible for interrupting the synthesis of DNA at every possible site in a population of molecules during nucleic acid base sequencing?
a.
2',3'-dideoxynucleotide
b.
3',5'-cyclic nucleotide
c.
Polynucleotide
d.
N-nucleotide
a.
2',3'-dideoxynucleotide
82
99. During a gene analysis, a DNA chip was scanned to analyze the fluorescence of the cDNA. The results showed a green dot. The green dot is an indication of a(n)_____.
a.
DNA sequence that bound to the cDNA from the treated cells
b.
RNA that was produced in untreated cells but not in treated cells
c.
mRNA that was produced in equal quantities in treated or untreated cells
d.
DNA sequences on the chip for which no mRNA was produced
b.
RNA that was produced in untreated cells but not in treated cells
83
Semiconservative replication implies that
a. each of the new double stranded DNA molecules contains one of the original intact strands and one completely new strand.
b. one of the new double stranded DNA molecules contains both of the original strands, while the other contains two new strands.
c. each of the new double stranded DNA molecules contains strands that are composed of segments of original and newly synthesized material.
d. None of these.
a. each of the new double stranded DNA molecules contains one of the original intact strands and one completely new strand.
84
Which strand of DNA is replicated exclusively in a discontinuous fashion?
a. lagging strand
b. leading strand
c. the strand that is read in a 5' to 3' direction
d. forward strand
a. lagging strand
85
The following enzyme is responsible for the bulk of DNA synthesis during replication:
a. DNA Polymerase I
b. DNA Polymerase II
c. DNA Polymerase III
d. DNA Polymerase IV
e. All four can make lots of DNA rapidly.
c. DNA Polymerase III
86
Which of the following joins Okazaki fragments during prokaryotic DNA replication?
a. DNA ligase
b. 3'--> 5' exonuclease activity of DNA polymerase III
c. RNase H
d. DNA primase
e. SSB (single-strand binding protein)
a. DNA ligase
87
What is the nucleophile in the DNA polymerase mechanism?
a. an oxygen anion on the terminal phosphate of the dNTP
b. the oxygen on the β-phosphate of the dNTP
c. the oxygen on the αα-phosphate of the dNTP
d. the 5′ hydroxyl on the deoxyribose
e. the 3′ hydroxyl on the deoxyribose
e. the 3′ hydroxyl on the deoxyribose
88
What is the need for a primer in transcription?
a. It ensures the fidelity of the newly synthesized RNA strand.
b. RNA polymerases requires a preexisting strand with a nucleotide having a 3'−OH.
c. RNA polymerase requires a preexisting strand with a nucleotide having a 5'−OH.
d. There is none.
d. There is none.
89
RNA synthesis begins at the base in the DNA sequence designated by the following number:
a. +1
b. 0
c. -1
d. -10
e. It varies between genes.
a. +1
90
What is the function of the sigma (σ) subunit of RNA polymerase in E. coli?
a. It contains the active site for synthesis of RNA.
b. It ensures proper processivity of the polymerase, so it doesn't stop prematurely.
c. It is involved in chain termination.
d. It scrunches the DNA.
e. It recognizes promoters where transcription should begin.
e. It recognizes promoters where transcription should begin.
91
The transcription of genes in E. coli that lack a termination sequence require _______ factor to terminate transcription.
a. rho
b. sigma
c. omega
d. TBP
a. rho
92
TATA-binding protein (TBP) is normally required for transcription by
a. Pol I
b. Pol II
c. Pol III
d. all of these polymerases.
e. none of these polymerases.
d. all of these polymerases.
93
Wobble allows a single codon to code for more than one amino acid. T/F
F
94
Given the following anticodon, with which mRNA codon would it pair? 5'-IGC-3'
a. 5'-ACU-3'
b. 5'-UCG-3'
c. 5'-GUA-3'
d. 5'-UCA-3'
e. 5'-GCU-3'
e. 5'-GCU-3'
95
The initial step in the formation of an aminoacyl-tRNA is
a. esterification of the tRNA
b. activation of the tRNA by reaction with ATP
c. activation of the amino acid by reaction with ATP
d. interaction of the mRNA with the tRNA
c. activation of the amino acid by reaction with ATP
96
Which of the following tRNA binding sites is correctly defined?
a. A site: accepts incoming aminoacyl-tRNA
b. E site: entrance site for initial tRNA binding
c. P site: site occupied by the tRNA that accepts the growing peptide chain
d. T site: site that is briefly occupied while the tRNA is passed from the A site to P site
e. all of the above
a. A site: accepts incoming aminoacyl-tRNA
97
Is the following statement true or false?
"The flow of genetic information in the cell is always DNA → RNA → protein."
Why?
False
In some cases, RNA information is translated to DNA.
98
Why is it necessary to unwind the DNA helix in the replication process?
The separation of the two strands of DNA requires an unwinding of the helix.
99
1. The flow of genetic information is RNA → DNA in
a) all organisms
b) all prokaryotes
c) retroviruses
d) no known organisms
c) retroviruses
100
2. What is the requirement for a template strand in DNA replication?
a) it serves as a guide in determining the next nucleotide to be added according to the Watson-Crick base pairing scheme
b) it serves as the start point for the new DNA strand
c) it allows the DNA polymerase to move along it easily
d) it is a substrate for the 3'-5' exonuclease activity
a) it serves as a guide in determining the next nucleotide to be added according to the Watson-Crick base pairing scheme
101
3. The famous Meselson and Stahl experiment showed:
a) DNA is replicated by a semi-conservative mechanism.
b) The direction of DNA synthesis proceeds 5' → 3'.
c) The isotope 15N is denser than 14N.
d) DNA replication is semi-conservative and 15N is denser than 14N.
e) All of these are correct.
a) DNA is replicated by a semi-conservative mechanism.
102
4. All the following describe the general mechanism of DNA synthesis, except:
a) One strand is made 5' → 3' while the other strand is made 3' → 5'.
b) The strands become separated during synthesis.
c) Synthesis occurs in both directions from the starting site of synthesis.
d) Synthesis of DNA is a very accurate process.
e) All of these are correct.
e) All of these are correct.
103
5. The direction of synthesis of DNA is
a) from the 5' end to the 3' end on both strands
b) from the 3' end to the 5' end on both strands
c) from the 5' end to the 3' end on one strand and from the 3' end to the 5' end on the other strand
d) none of the above
a) from the 5' end to the 3' end on both strands
104
6. An important process in the synthesis of new DNA is
a) proofreading and repair
b) unwinding of the double helix
c) protection of single-stranded regions from nuclease action
d) all of the above
d) all of the above
105
7. When the synthesis of new DNA is directed by an original template DNA molecule
a) the DNA produced has two newly formed strands (no change in the original DNA)
b) two DNA molecules are formed, each with one new strand and one strand from the original DNA
c) there is random arrangement of newly formed and original DNA on the two strands of the DNA produced
d) no information is available on this subject
b) two DNA molecules are formed, each with one new strand and one strand from the original DNA
106
8. The many subunits of DNA Polymerase III are needed to do all the following, except:
a) Polymerization.
b) Ligating the final products.
c) Proofreading.
d) Clamping on to the template.
e) All of these.
b) Ligating the final products.
107
9. The universal features of DNA replication include all the following, except:
a) Release of PPi from a nucleoside triphosphate.
b) Synthesis from the 5' end to the 3' end.
c) Base pairing of A to T and G to C.
d) Use of a primer.
e) All of these describe DNA synthesis.
e) All of these describe DNA synthesis.
108
10. The primer for in vivo DNA replication is:
a) The 3' hydroxyl of the preceding Okazaki fragment.
b) A short piece of RNA.
c) A nick made in the DNA template.
d) A primer is not always required for DNA replication.
e) All of these are true.
b) A short piece of RNA.
109
11. Strands always grow in the 3' → 5' direction.
a) True
b) False
b) False
110
12. In E. coli, the leading strand is synthesized discontinuously while the lagging strand is synthesized in one piece.
a) True
b) False
b) False
111
13. Okazaki fragments are short DNA pieces that explain how DNA is synthesized on both strands.
a) True
b) False
b) False
112
14. What is the need for a primer strand in DNA replication?
a) it ensures the fidelity of the newly synthesized DNA strand
b) the DNA polymerases require a preexisting strand with a nucleotide having a 3'-OH
c) the DNA polymerases require a preexisting strand with a nucleotide having a 5'-OH
d) it ensures the integrity of the new DNA
b) the DNA polymerases require a preexisting strand with a nucleotide having a 3'-OH
113
15. Nicked segments of single-stranded DNA are linked by
a) DNA polymerase
b) DNA-binding protein
c) DNA ligase
d) DNA gyrase
c) DNA ligase
114
16. Optimal DNA replication requires the coordinated effort of all of the following, except:
a) Primase
b) DNA Polymerase II.
c) Single strand binding proteins.
d) Gyrase
e) All of these are necessary.
b) DNA Polymerase II.
115
1. The enzyme that attaches the Okazaki fragments together is called a ligase.
a) True
b) False
a) True
116
18. Repair of DNA is usually carried out by
a) hydrolysis of the entire damaged DNA molecule and synthesis of new DNA
b) hydrolysis of one strand of the damaged DNA molecule and synthesis of a new strand
c) a cut-and patch process
d) introducing additional supercoiling in the molecule
c) a cut-and patch process
117
19. The proofreading of DNA is especially good because "the identity of each base pair is checked before the enzyme moves on to the next base pair."
a) True
b) False
a) True
118
20. DNA repair mechanisms usually require an endonuclease to "nick" the duplex, so the repair enzymes can have access to the end of a DNA strand.
a) True
b) False
a) True
119
21. It is so important to keep the DNA molecule fully connected that some repair mechanisms will actually allow mismatches or deletions from the DNA.
a) True
b) False
b) False
120
22. Ultra-violet light principally causes which of the following damages to DNA?
a) mismatches between stands
b) breaks in the phosphodiester backbone of the DNA strand
c) thymine dimerization
d) methylation of specific bases
c) thymine dimerization
121
23. Since DNA Polymerase II has endonuclease activity, it is able to proofread its product when it is used in DNA repair.
a) True
b) False
b) False
122
24. One of the most important ways in which DNA is modified after synthesis is
a) methylation of bases
b) covalent binding of proteins to the sugar moieties
c) splicing of RNA "leaders"
d) electrostatic binding of negatively charged counterions
a) methylation of bases
123
1. Which of the following strategies is used in DNA repair?
a) nick translation
b) mismatch repair
c) base excision repair
d) all of the above
d) all of the above
124
26. Thymine dimers are most often caused by
a) improper function of DNA polymerase proofreading.
b) ionizing radiation.
c) free radicals.
d) ultraviolet radiation.
d) ultraviolet radiation.
125
27. In eukaryotic, but not prokaryotic, DNA replication
a) topoisomerases are required
b) a primer is needed on the lagging strand only
c) histone biosynthesis must take place
d) there is only one origin of replication
c) histone biosynthesis must take place
126
28. One of the most important ways in which eukaryotic DNA differs from that of prokaryotes is
a) prokaryotic DNA is complexed to proteins whereas eukaryotic DNA is not
b) eukaryotic DNA is complexed to proteins whereas prokaryotic DNA is not
c) DNA synthesis in eukaryotes takes place in the opposite direction from that in prokaryotes
d) there is no requirement for a primer in the synthesis of eukaryotic DNA
b) eukaryotic DNA is complexed to proteins whereas prokaryotic DNA is not
127
29. Replication of eukaryotic DNA
a) must occur faster than replication of prokaryotic DNA
b) must be controlled to coordinate with the cell cycle
c) takes place during mitosis
d) takes place twice during each cell cycle
b) must be controlled to coordinate with the cell cycle
128
30. Linear eukaryotic DNA molecules have many origins of synthesis, while circular bacterial DNA usually have only one.
a) True
b) False
a) True
129
31. Differences between DNA polymerases in eukaryotes and bacteria include all, except:
a) Some eukaryotic polymerases include a primase.
b) All the eukaryotic enzymes are polymeric.
c) Eukaryotes require a special enzyme to remove the RNA primer.
d) Some eukaryotic polymerases include a primase and all are polymeric.
e) All of these are correct.
e) All of these are correct.
130
32. Transcription of RNA and replication of DNA are similar in all these ways, except:
a) Nucleoside triphosphates are the precursors.
b) Both strands of DNA are copied.
c) Base pairing is used to copy the sequence in a precise manner.
d) The chain grows for the 5' to the 3' end.
e) All of these are similarities between RNA and DNA synthesis.
b) Both strands of DNA are copied.
131
33. All the following statements describe the general mechanism of RNA synthesis, except:
a) The DNA strands become separated during synthesis
b) Synthesis of RNA is a very accurate process
c) The template strand is read in the 3' → 5' direction
d) All 4 ribonucleotides are required
e) All of these describe RNA synthesis
b) Synthesis of RNA is a very accurate process
132
34. The universal features of RNA transcription include all the following, except:
a) Release of PPi from a nucleoside triphosphate
b) Synthesis from the 5' end to the 3' end
c) Base pairing of A to U and G to C
d) Use of a primer
e) All of these describe RNA synthesis.
d) Use of a primer
133
35. RNA transcription differs from DNA replication in all of these ways, except:
a) Substrates
b) Primer
c) Proofreading
d) Template use
e) All of these are different between RNA and DNA synthesis.
e) All of these are different between RNA and DNA synthesis.
134
36. The sigma (σ) subunit has all the following properties, except:
a) It tells the RNA Poly where to sit down.
b) It helps point the RNA Pol in the proper direction.
c) It causes the RNA Pol to bind tightly to the DNA.
d) It stays with the RNA Pol throughout synthesis.
e) All of these describe the sigma factor.
d) It stays with the RNA Pol throughout synthesis.
135
37. These terms can be used interchangeably to denote the complementary strand in DNA, except:
a) Template strand
b) Coding strand
c) Antisense strand
d) Negative or "-" strand
e) All these terms describe the complementary DNA strand
b) Coding strand
136
38. Chain termination occurs, in vivo, when:
a) RNA Pol gets to the end of the DNA.
b) The factor called rho (ρ) binds to the DNA.
c) A hairpin loop forms in the template.
d) Either a hairpin loop forms or rho is involved.
e) All of these.
d) Either a hairpin loop forms or rho is involved.
137
39. The enzyme principally responsible for RNA synthesis in Escherichia coli
a) is a multisubunit enzyme
b) consists of a single polypeptide chain
c) requires Mn2+ for activity
d) requires a DNA primer
a) is a multisubunit enzyme
138
40. Which of the following correctly describes a difference between RNA & DNA polymerases?
a) RNA polymerases usually do not need a template, while DNA polymerases do.
b) DNA polymerases usually require a primer (i.e., they can only continue a strand, not start one), while most RNA polymerases do not.
c) RNA polymerases usually synthesize introns, while DNA polymerases synthesize cistrons.
d) RNA polymerases polymerize 5' —> 3', while DNA polymerases polymerize 3' —> 5'.
b) DNA polymerases usually require a primer (i.e., they can only continue a strand, not start one), while most RNA polymerases do not.
139
41. Operator regions at the end of prokaryotic genes contain all the following, except:
a) The binding site for repressors.
b) The binding site for RNA Pol.
c) The binding site for factors which enhance RNA polymerization.
d) The binding site for sigma factor.
e) All of these.
e) All of these.
140
42. Which of the following offers the best description of a Pribnow box?
a) A promoter consensus sequence located at approximately -35.
b) A promoter consensus sequence located at approximately -10.
c) A sequence forming a hairpin loop signaling the termination of transcription.
d) A sequence immediately surrounding the start site of transcription.
b) A promoter consensus sequence located at approximately -10.
141
43. RNA polymerase
a) can bind at any location on DNA to start RNA synthesis
b) incorporates nucleotides into growing RNA from the 3' to the 5' end
c) uses a template strand of to specify the sequence of bases in RNA
d) has 3' → 5' exonuclease activity
c) uses a template strand of to specify the sequence of bases in RNA
142
44. The promoter site is
a) the start site for transcription in DNA
b) the binding site for regulatory proteins that stimulate transcription
c) the general region of DNA downstream from the start site
d) the site on DNA at which RNA polymerase binds to initiate transcription
d) the site on DNA at which RNA polymerase binds to initiate transcription
143
45. Initiation of RNA biosynthesis involves
a) recognition of the promoter region by the α subunit of RNA polymerase
b) conversion of the closed-promoter complex to the open-promoter complex
c) binding of one of the α subunits of RNA polymerase to each strand of DNA
d) incorporation of four pyrimidine nucleotides in succession
b) conversion of the closed-promoter complex to the open-promoter complex
144
46. What is the need for a primer strand in transcription?
a) it ensures the fidelity of the newly synthesized RNA strand
b) there is none
c) RNA polymerases requires a preexisting strand with a nucleotide having a 3'-OH
d) RNA polymerase requires a preexisting strand with a nucleotide having a 5'-OH
b) there is none
145
47. Which is not associated with bacterial promoters?
a) the transcription start site
b) the Pribnow box
c) the -35 element
d) 3 antiterminator
d) 3 antiterminator
146
48. The promoter region of DNA
a) contains sequences that direct the binding of RNA polymerase
b) tends to be G-C rich
c) starts at the start of transcription and contains the coding region for the first 15 nucleotides incorporated into RNA
d) binds specifically to the core RNA polymerase
a) contains sequences that direct the binding of RNA polymerase
147
49. In prokaryotic RNA synthesis
a) the rate of incorporation of nucleotides is constant throughout the elongation process
b) the ρ (rho) protein is always required for termination
c) a unique series of three bases leads to termination
d) inverted-repeat sequences in the DNA being transcribed can lead to termination
d) inverted-repeat sequences in the DNA being transcribed can lead to termination
148
50. The promoter region is one term use to describe where RNA Pol binds to DNA.
a) True
b) False
a) True
149
51. Operons
a) control the expression of constitutive genes
b) are subject to positive or to negative control
c) are not affected by mutations in the genes for repressors or inducers
d) occur in both prokaryotes and eukaryotes
b) are subject to positive or to negative control
150
52. The timing of expression of an operon in E. coli is influenced by all of the following, except:
a) Repressors
b) Co-repressors
c) Presence of substrates of the operon which need to be degraded
d) Inducers
e) All of these influence the timing of expression
a) Repressors
151
53. The amount of expression of an operon in E. coli is influenced by all of the following, except:
a) Availability of the specific sigma factor for that operon.
b) How well the Pribnow box conforms to the consensus sequence.
c) Attenuation mechanisms.
d) Presence of 3' 5' cyclic AMP.
e) All of these.
e) All of these.
152
54. A mutation in the lac A gene would result in
a) continuous production of the proteins encoded by the three structural genes
b) continuous production of the lac repressor
c) normal operation of the lac operon, but with an alteration in the proteins encoded by the lac A gene
d) no transcription from the lac operon
c) normal operation of the lac operon, but with an alteration in the proteins encoded by the lac A gene
153
55. Cyclic AMP affects transcription by
a) triggering the action of several protein factors
b) phosphorylating a subunit of RNA polymerase
c) phosphorylating a transcription factor
d) inhibiting DNA looping
a) triggering the action of several protein factors
154
56. Control of transcription in prokaryotes does not involve
a) enhancers
b) silencers
c) leucine zipper proteins
d) alternative σ factors
c) leucine zipper proteins
155
57. Which of the following is not a characteristic of catabolite activator protein (CAP)?
a) it is a positive regulator of the lac operon
b) when the cell has sufficient glucose and lactose, CAP will not be bound to the CAP binding site
c) CAP binding near the promoter site depends on CAP complexation with cAMP
d) the binding of CAP to DNA requires ATP hydrolysis
d) the binding of CAP to DNA requires ATP hydrolysis
156
58. The following are all true about eukaryotic and prokaryotic RNA polymerases, except:
a) There are 3 different RNA polymerases in eukaryotes, instead of just one.
b) Eukaryotic polymerases have the same number of subunits as prokaryotic ones.
c) Only prokaryotic polymerases use sigma factor.
d) The enzymatic mechanism is the same for both types of organisms.
e) All of these are true.
b) Eukaryotic polymerases have the same number of subunits as prokaryotic ones.
157
59. Which enzyme transcribes genes encoding tRNA in eukaryotes?
a) RNA polymerase I
b) RNA polymerase II
c) RNA polymerase III
d) Different tRNAs are transcribed by different RNA polymerases.
c) RNA polymerase III
158
60. The following are all key steps in activation of mRNA synthesis in eukaryotes, except:
a) Binding of TBP to the DNA.
b) Binding of other transcription factors.
c) Binding of RNA Pol I.
d) Phosphorylation of the RNA Pol.
e) All of these are necessary to initiate RNA synthesis in eukaryotes.
e) All of these are necessary to initiate RNA synthesis in eukaryotes.
159
61. Transcription in eukaryotes differs from RNA synthesis in prokaryotes
a) by requiring a primer
b) by simplifying the process with multifunctional enzymes
c) in using more complex σ factors
d) by having three RNA polymerases rather than one
c) in using more complex σ factors
160
62. RNA polymerases from prokaryotes and eukaryotes
a) have sequence homology in catalytic subunits
b) have identical σ factors
c) differ because there is no analogue to the prokaryotic α subunit in eukaryotes
d) have the same number and kind of subunits
a) have sequence homology in catalytic subunits
161
63. A frequently encountered aspect of binding of RNA polymerase II to its promoter is
a) the lack of upstream elements
b) the presence of the TATA box
c) the highly conserved sequence at the start of transcription
d) the requirement for downstream elements
b) the presence of the TATA box
162
64. A transcription factor is
a) a subunit of RNA polymerase II that does not have a prokaryotic analogue
b) the part of the promoter sequence closest to the start of transcription
c) a protein other than RNA polymerase that is involved in transcription
d) a sequence that determines whether an upstream element will be an enhancer or silencer
c) a protein other than RNA polymerase that is involved in transcription
163
65. An aminoacyl-tRNA is initially bound to the ribosome
a) at the A site on the 50S subunit
b) at the P site on the 50S subunit
c) at the A site on the 30S subunit
d) at the P site on the 30S subunit
a) at the A site on the 50S subunit
164
66. In protein synthesis formation of new peptide bonds is catalyzed by
a) elongation factor EF-Tu
b) elongation factor EF-Ts
c) elongation factor EF-G
d) peptidyl transferase
d) peptidyl transferase
165
67. After peptide bond formation takes place, what step is necessary for continuation of protein synthesis?
a) binding of uncharged tRNA to the ribosome
b) binding of EF-Tu
c) binding of EF-Ts
d) translocation of the ribosome
d) translocation of the ribosome
166
68. The match between codon and anticodon is one of the many proofreading aspects of protein synthesis.
a) True
b) False
a) True
167
69. Which of the following is necessary for chain termination in protein synthesis?
a) termination codons of mRNA
b) release factors
c) GTP
d) all of the above
d) all of the above
168
70. Protein synthesis in prokaryotes always starts with
a) a methionine residue
b) a formylmethionine residue
c) a cysteine residue
d) no specific residue
b) a formylmethionine residue
169
71. The formylation of methionine in prokaryotes
a) depends on two different tRNAs, where methionine can be formylated when bound to one form and not the other
b) depends on two different tRNAs, where methionine can be formylated when bound to either one
c) depends on one tRNA, where methionine is formylated after binding
d) takes place before methionine is bound to tRNA
a) depends on two different tRNAs, where methionine can be formylated when bound to one form and not the other
170
72. A polysome is
a) a complex consisting of one mRNA to which several ribosomes are attached
b) a polypeptide chain in the process of being formed
c) an intermediate stage in the self-assembly of ribosomes
d) an aggregate of ribosomal proteins
a) a complex consisting of one mRNA to which several ribosomes are attached
171
73. In bacteria, translation of the mRNA begins during the synthesis of the mRNA.
a) True
b) False
a) True
172
74. The formyl group is added to methionine prior to attaching it to the initial tRNA.
a) True
b) False
b) False
173
75. In bacteria, each mRNA will bind to only one ribosome at a time.
a) True
b) False
b) False
174
76. A Shine-Dalgarno Sequence is a
a) sequence of nucleotides in the DNA that interacts with the σ-subunit of RNA polymerase to begin transcription.
b) sequence of nucleotides in an mRNA that interacts with the small subunit of a ribosome to begin translation.
c) sequence of nucleotides in the DNA that interacts with ρ-protein to terminate transcription.
d) sequence of nucleotides in an mRNA that functions to terminate translation.
b) sequence of nucleotides in an mRNA that interacts with the small subunit of a ribosome to begin translation.
