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Chapter 8. Chemical Carcinogenesis
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There is evidence that certain dietary components are carcinogenic. Which of the following is NOT tabbed as a dietary carcinogen?
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a. excessive caloric intake.
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b. excessive alcohol consumption.
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c. aflatoxin B1 (a food contaminant).
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d. insufficient caloric intake.
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e. nitrites (found in some lunchmeats).
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Which of the following statements regarding mechanisms of chemical carcinogenesis is FALSE?
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a. Procarcinogens require metabolism in order to exert their carcinogenic effect.
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b. Free radicals are highly reactive molecules that have a single, unpaired electron.
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c. DNA adducts interfere with the DNA replication machinery.
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d. Mutations in the DNA and failure to repair those mutations can be highly carcinogenic.
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e. Biological reduction of molecular oxygen is the only way free radicals can be formed.
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In addition to being necessary for transcription to occur, which of the following transcription factors also plays a crucial role in nucleotide excision repair?
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Which of the following statements regarding DNA repair is true?
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a. Base excision repair requires the removal of a longer piece of DNA in comparison with nucleotide excision repair.
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b. The repair of double-stranded DNA breaks is more prone to error than is base excision repair.
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c. Dimerization of pyrimidines is repaired via base excision repair.
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d. Mismatch repair can only recognize normal nucleotides that are paired with a noncomplementary nucleotide.
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e. Nucleotide excision and base excision are tolerance mechanisms used to respond to DNA damage.
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Which of the following statements is a characteristic of the initiation stage of carcinogenesis?
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a. Initiation is reversible in viable cells.
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b. The dose–response exhibits an easily measurable threshold.
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c. Cell division is required for the fixation of the process.
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d. All initiated cells survive over the lifespan of the organism.
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e. Spontaneous initiation of cells is a rare occurrence.
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Tumor suppressor genes are ...