CHAPTER 9: Genetic Toxicology

Chapter 9. Genetic Toxicology

Oncogenes:

a. maintain normal cellular growth and development.

b. exert their action in a genetically recessive fashion.

c. are often formed via translocation to a location with a more active promoter.

d. can be mutated to form proto-oncogenes.

e. include growth factors and GTPases, but not transcription factors.

Which of the following is NOT one of the more common sources of DNA damage?

a. ionizing radiation.

b. UV light.

c. electrophilic chemicals.

d. DNA polymerase error.

e. x-rays.

Which of the following pairs of DNA repair mechanisms is most likely to introduce mutations into the genetic composition of an organism?

a. nonhomologous end-joining (NHEJ) and base excision repair.

b. nonhomologous end-joining and homologous recombination.

c. homologous recombination and nucleotide excision repair.

d. nucleotide excision repair and base excision repair.

e. homologous recombination and mismatch repair.

Which of the following DNA mutations would NOT be considered a frameshift mutation?

a. insertion of 5 nucleotides.

b. insertion of 7 nucleotides.

c. deletion of 18 nucleotides.

d. deletion of 13 nucleotides.

e. deletion of 1 nucleotide.

Which of the following base-pair mutations is properly characterized as a transversion mutation?

a. T → C.

b. A → G.

c. G → A.

d. T → U.

e. A → C.

All of the following statements regarding nondisjunction during meiosis are true EXCEPT:

a. Nondisjunction events can happen during meiosis I or meiosis II.

b. All gametes from nondisjunction events have an abnormal chromosome number.

c. Trisomy 21 (Down syndrome) is a common example of nondisjunction.

d. In a nondisjunction event in meiosis I, homologous chromosomes fail to separate.

e. The incorrect formation of spindle fibers is a common cause of ...