GEN 3020 test 3 mastering chapter 15 – Flashcards
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Which nucleotide will base‑pair with the enol form of 5‑bromouracil?
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guanine
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Which of the following events could result in a frameshift mutation?
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base deletion
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Generally speaking, which of the following mutations would most severely affect the protein coded for by a gene?
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a frameshift deletion at the beginning of the gene
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Mutations that arise in nature, from no particular artificial agent, are called ________.
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spontaneous mutation
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Which of the following statements about deamination is true?
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Deamination is induced by nitrous acid.
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Considering the electromagnetic spectrum, identify likely mutagens from the following list: radio waves, microwaves, infrared, ultraviolet, X-rays, gamma rays, cosmic rays.
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gamma, xray, cosmic, UV
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What are the consequences of having pyrimidine dimers in DNA?
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These dimers distort the DNA structure and result in errors during DNA replication.
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Which of the following statements regarding Nucleotide Excision Repair (NER) and Base Excision Repair (BER) is true?
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Both NER and BER involve the removal of one or more damaged bases by a nuclease.
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In terms of its involvement in mutagenesis, 5BU is best described as _______.
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a base analog that can cause either A-T > G-C or G-C > A-T transitions
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For 5BU to cause a transition mutation, which of the following must occur?
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DNA with incorporated 5BU must replicate.
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In its rare form, 5BU pairs with guanine.
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true
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Patients with Huntington disease exhibit __________.
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a triplet sequence repeated many times
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Ultraviolet light causes pyrimidine dimers to form in DNA. Some individuals are genetically incapable of repairing some dimers at "normal" rates. Such individuals are likely to suffer from ________.
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XP
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Which enzyme is responsible for proofreading during replication?
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DNA polymerase
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The purpose of the Ames Test is to _______.
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test the mutagenic effects of chemicals
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Why are liver extracts used in the Ames test?
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Liver enzymes may activate some innocuous compounds, making them mutagenic.
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Which bacteria grow on the agar plate if the Ames test is positive?
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his+ prototrophs
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Which repair process in E. coli uses visible light to repair thymine dimers?
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photoreactivation repair
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Which two repair processes are the most error prone?
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-nonhomologous end joining
-translesion DNA synthesis
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Which repair process(es) use(s) a DNA polymerase?
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nucleotide excision repair
homologous recombination (synthesis-dependent strand annealing)
translesion DNA synthesis
base excision repair
