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Chapter 8. Chemical Carcinogenesis

There is evidence that certain dietary components are carcinogenic. Which of the following is NOT tabbed as a dietary carcinogen?

a. excessive caloric intake.

b. excessive alcohol consumption.

c. aflatoxin B1 (a food contaminant).

d. insufficient caloric intake.

e. nitrites (found in some lunchmeats).

Which of the following statements regarding mechanisms of chemical carcinogenesis is FALSE?

a. Procarcinogens require metabolism in order to exert their carcinogenic effect.

b. Free radicals are highly reactive molecules that have a single, unpaired electron.

c. DNA adducts interfere with the DNA replication machinery.

d. Mutations in the DNA and failure to repair those mutations can be highly carcinogenic.

e. Biological reduction of molecular oxygen is the only way free radicals can be formed.

In addition to being necessary for transcription to occur, which of the following transcription factors also plays a crucial role in nucleotide excision repair?

a. TFIIA.

b. TFIIB.

c. TFIID.

d. TFIIF.

e. TFIIH.

Which of the following statements regarding DNA repair is true?

a. Base excision repair requires the removal of a longer piece of DNA in comparison with nucleotide excision repair.

b. The repair of double-stranded DNA breaks is more prone to error than is base excision repair.

c. Dimerization of pyrimidines is repaired via base excision repair.

d. Mismatch repair can only recognize normal nucleotides that are paired with a noncomplementary nucleotide.

e. Nucleotide excision and base excision are tolerance mechanisms used to respond to DNA damage.

Which of the following statements is a characteristic of the initiation stage of carcinogenesis?

a. Initiation is reversible in viable cells.

b. The dose–response exhibits an easily measurable threshold.

c. Cell division is required for the fixation of the process.

d. All initiated cells survive over the lifespan of the organism.

e. Spontaneous initiation of cells is a rare occurrence.

Tumor suppressor genes are ...

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