Chemical carcinogenesis Flashcards
There is evidence that certain dietary components are carcinogenic. Which of the followint 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)
d. insufficient caloric intake
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
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
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
b. The repair of double-stranded DNA breaks is more prone to error than is base excision repair
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.
c. Cell division is required for the fixation of the process
Tumor suppressor genes are mutated in a majority of cancers. Which of the following is NOT a characteristic of a tumor suppressor gene?
A. A mutation in a tumor suppressor gene is dominant.
b. Germ line inheritance of a mutated tumor suppressor gene is often involved with cancer development
c. There is considerable tissue specificity for cancer development
d. The p53 gene is a tumor suppressor gene that also acts as a transcription factor
e. Mutations in tumor suppressor genes can result in loss of cell cycle control.
A. A mutation in a tumor suppressor gene is dominant.
Which of the following molecules does NOT play an important role in cell cycle regulation?
a. p53
b. cyclin-D
c. MAPK
d. MHC
e. E2F
d. MHC
which of the following environmental factors is proportionally responsible for the LEAST amount of cancer deaths?
a. tobacco
b. infection
c. diet
d. sexual behavior
e. alcohol
e. alcohol
The evidence of the carcinogenicity of dietary intake is sufficient to include one’s diet as associated with neoplasms of all of the following EXCEPT:
a. colon
b. breast
c. pancreas
d. endometrium
e. gallbladder
c. pancreas
which of the following is the correct definition of a complete carcinogen?
A. a chemical capable only of initiating cells
B. a chemical possessing the ability of inducing cancer from normal cells, usually possessing properties of initiating, promoting and progression agents.
C. a chemical capable of converting an initiated cell or a cell in the stage of promotion to a potentially malignant cell
D. a chemical capable of causing the expansion of initiated cell clones
E. a chemical that will cause cancer 100% of the time that it is administered.
B. a chemical possessing the ability of inducing cancer from normal cells, usually possessing properties of initiating, promoting and progression agents.
