Download Molecular Genetics Multiple Choice Identify the letter of the choice

Molecular Genetics
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
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1. Replicating the lagging strand of DNA-that is, adding bases in the 3' 5' direction-utilizes which of the
following?
a. DNA ligase
c. Okazaki fragments
e. A, B, and C
b. RNA primers
d. A and B only
2. In his transformation experiments, Frederick Griffith observed that
a. mutant mice were resistant to bacterial infections.
b. mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can
convert some of the living cells into the pathogenic form.
c. mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes
the pathogenic strain nonpathogenic.
d. infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic
strains.
e. mice infected with a pathogenic strain of bacteria can spread the infection to other mice.
3. For a science fair project, two students decided to repeat the Hershey and Chase experiment, with
modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They
reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the
nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work?
a. There is no radioactive isotope of nitrogen.
b. Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would
not distinguish between DNA and proteins.
c. Meselson and Stahl already did this experiment.
d. Although there are more nitrogens in a nucleotide, labeled phosphates actually have 16
extra neutrons; therefore, they are more radioactive.
Questions 4 - 6 Match the investigator(s) to the appropriate discovery of about the nature of genes.
A. Frederick Griffith
B. Alfred Hershey and Martha Chase
C. Oswald Avery, Maclyn McCarty, and Colin MacLeod
D. Erwin Chargaff
E. Matthew Meselson and Franklin Stahl
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4. Chemicals from heat-killed S cells were purified. The chemicals were tested for the ability to transform
live R cells. The transforming agent was found to be DNA.
a. A
b. B
c. C
d. D
e. E
5. Bacteriophage with labeled proteins or DNA was allowed to infect bacteria. It was shown that the DNA,
but not the protein, entered the bacterial cells, and was therefore the genetic material.
a. A
b. B
c. C
d. D
e. E
6. In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of
guanine equals the amount of cytosine.
a. A
b. B
c. C
d. D
e. E
7. It became apparent to Watson and Crick after completion of their model that the DNA molecule could
carry a variety of hereditary information in its
a. sequence of bases.
d. side groups of nitrogenous bases.
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b. phosphate-sugar backbones.
e. different five-carbon sugars.
c. complementary pairing of bases.
Which of the following best describes the addition of nucleotides to a growing DNA chain?
a. A nucleoside triphosphate is added to the 5' end of the DNA, releasing a molecule of
pyrophosphate.
b. A nucleoside triphosphate is added to the 3' end of the DNA, releasing a molecule of
pyrophosphate.
c. A nucleoside diphosphate is added to the 5' end of the DNA, releasing a molecule of
phosphate.
d. A nucleoside diphosphate is added to the 3' end of the DNA, releasing a molecule of
phosphate.
e. A nucleoside monophosphate is added to the 3' end of the DNA.
Which of the following help to hold the DNA strands apart while they are being replicated?
a. primase
d. single-strand binding proteins
b. ligase
e. exonuclease
c. DNA polymerase
Which of the following situations is most like telomeres?
a. the pull tab on a soft drink can
b. the two ends of a shoelace
c. the central spindle that a CD fits around while in the case
d. the mechanism of a zipper that allows the separated parts to be joined
e. the correct letters used to replace errors in a document after they have been deleted in a
word processor
Which of the following represents a similarity between RNA and DNA?
a. Both are double-stranded.
b. the presence of uracil
c. the presence of an OH group on the 2' carbon of the sugar
d. nucleotides consisting of a phosphate, sugar, and nitrogenous base
e. Both are found exclusively in the nucleus.
Using RNA as a template for protein synthesis instead of translating proteins directly from the DNA is
advantageous for the cell because
a. RNA is much more stable than DNA.
b. RNA acts as an expendable copy of the genetic material, allowing the DNA to serve as a
permanent copy of the genetic material.
c. many mRNA molecules can be transcribed from a single gene, decreasing the potential
rate of gene expression.
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’ AGT 5’.
b. 3’ ACU 5’.
c. 5’ TCA 3’.
d. 5’ ACU 3’.
Use the table of codons below to answer the following questions.
____ 14. 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'.
d. 3' AUA-AAT-ATA-ACA 5'.
b. 3' AAC-GAC-GUC-AUA 5'.
e. 3' AAA-GAA-TAA-CAA 5'.
c. 5' AUG-CTG-CAG-TAT 3'.
____ 15. What is the amino acid sequence of a protein based on the mRNA sequence 5' UUUUCUUAUUGUCUU
3' ?
a. leu-cys-tyr-ser-phe
c. phe-leu-ile-met-val
e. cys-phe-tyr-cys-leu
b. phe-ser-tyr-cys-leu
d. leu-pro-asp-lys-gly
____ 16. What amino acid sequence will be generated, based on the following mRNA codon sequence?
5'AUG-UCU-UCG-UUA-UCC-UUG
a. met-arg-glu-arg-glu-arg
c. met-ser-leu-ser-leu-ser
e. met-leu-phe-arg-glu-glu
b. met-glu-arg-arg-gln-leu
d. met-ser-ser-leu-ser-leu
____ 17. A protein has the sequence phe-pro-lys-gly-phe-pro. Which of the following DNA sequences is the
coding strand for this protein?
a. 5' TTT-CCC-AAA-GGG-TTT-CCC 3’
d. 5' GGG-AAA-CCC-TTT-GGG-AAA 3’
b. 3' GGG-AAA-CCC-TTT-GGG-AAA 5’ e. 3' TTT-CCC-AAA-GGG-TTT-CCC 5’
c. 5' ACT-TAC-CAT-AAA-CAT-TAC 3’
____ 18. A codon
a. consists of two nucleotides.
d. catalyzes RNA synthesis.
b. may code for the same amino acid as
e. is found in all eukaryotes, but not in
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another codon.
prokaryotes.
c. consists of discrete amino acid regions.
What are the coding segments of a stretch of eukaryotic DNA called?
a. introns
b. exons
c. codons
d. replicons
e. transposons
A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting
of 400 amino acids. This is best explained by the fact that
a. many noncoding 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.
Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes
a. excision of introns.
d. union with ribosomes.
b. fusion into circular forms known as
e. fusion with other newly transcribed
plasmids.
mRNA.
c. linkage to histone molecules.
All of the following are directly involved in translation except
a. mRNA.
b. tRNA.
c. ribosomes.
d. DNA.
The genetic code is essentially the same for all organisms. From this, one can logically assume all of the
following EXCEPT
a. a gene from an organism could theoretically be expressed by any other organism.
b. all organisms have a common ancestor.
c. DNA was the first genetic material.
d. the same codons in different organisms usually translate into the same amino acids.
e. different organisms have the same number of different types of amino acids.
A particular triplet of DNA bases is AAA. The anticodon on the tRNA that will match the mRNA codon
is
a. TTT.
b. UUA.
c. UUU.
d. AAA.
A part of an mRNA molecule with the following sequence is being read by a ribosome: 5' CCG-ACG 3'
(mRNA). The following 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.
tRNA Anticodon
GGC
CGU
UGC
CCG
ACG
CGG
Amino Acid
Proline
Alanine
Threonine
Glycine
Cysteine
Alanine
The dipeptide that will form will be
a. cysteine-alanine. c. glycine-cysteine. d. alanine-alanine.
e. threonine-glycine.
b. proline-threonine.
____ 26. Of the following types of mutations, which one occurs during meiosis?
a. Inversion
c. Substitution
d. Translocation
e. Duplication
b. Deletion
Each of the following is a modification of the sentence THECATATETHERAT.
A.THERATATETHECAT
B. THETACATETHERAT
C. THECATARETHERAT
D. THECATATTHERAT
E. CATATETHERAT
____ 27. Which of the above is analogous to a frameshift mutation?
a. A
b. B
c. C
d. D
____ 28. Plasmids are important in biotechnology because they are
a. a vehicle for the insertion of foreign genes into bacteria.
b. recognition sites on recombinant DNA strands.
c. surfaces for protein synthesis in eukaryotic recombinants.
d. surfaces for respiratory processes in bacteria.
e. proviruses incorporated into the host DNA.
____ 29. The polymerase chain reaction is important because it allows us to
a. insert eukaryotic genes into prokaryotic plasmids.
b. incorporate genes into viruses.
c. make DNA from RNA transcripts.
d. make many copies of a targeted segment of DNA.
e. insert regulatory sequences into eukaryotic genes.
e. E
The following questions refer to the techniques, tools, or substances listed below. Answers may be used
once, more than once, or not at all.
A. restriction enzymes
B. PCR
C. gel electrophoresis
____ 30. ____ produces multiple identical copies of a gene for basic research or for large-scale production of a
gene product
a. A
b. B
c. C
d. D
e. E
____ 31. ____ separates molecules by movement due to size and electrical charge
a. A
b. B
c. C
d. D
e. E
____ 32. ____ cuts DNA molecules at specific locations
a. A
b. B
c. C
d. D
e. E
____ 33. The segment of DNA shown in the figure below has restriction sites I and II, which create restriction
fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the
separation and identity of these fragments?
a.
c.
b.
d.
e.
____ 34. Genetically engineered plants
a. are more difficult to engineer than animals.
b. include transgenic crops that can increase the food supply.
c. are being discussed, but traditional plant breeding programs are still the only method used
to develop new plants.
d. are banned throughout the world.
____ 35. Current applications of biotechnology include
a. cleaning up toxic waste.
b. development of artificial photosynthetic machines.
c. manufacturing human growth hormones and other gene therapies.
d. A and C only
e. A, B, and C