Genetic toxicology

Question 1

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 promotor
d. can be mutated to form proto-oncogenes.
e. include growth factors and GTPases, but not transcription factors

Answer 1

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

Question 2

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. DNS polymerase error
e. x-rays

Answer 2

d. DNS polymerase error

Question 3

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. holologous recombination and mismatch repair

Answer 3

b. nonhomologous end-joining and homologous recombination

Question 4

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

Answer 4

c. deletion of 18 nucleotides

Question 5

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

a. T–>C
b. A–>G
c. G–>A
d. T–>U
e. A–>C

Answer 5

e. A–>C

Question 6

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 nondisjunction during meiosis

Answer 6

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

Question 7

Which of the following diseases does NOT have a recessive inheritance pattern?

a. phenylketonuria
b. cystic fibrosis
c. Tay-Sachs disease
d. sickle cell anemia
e. Huntington’s disease

Answer 7

e. Huntington’s disease

Question 8

What is the purpose of the AMES assay?

a. To determine the threshold of UV light bacteria can receive before having mutations in their DNA
b. to measure the frequency of aneuploidy in bacterial colonies treated with various chemicals
c. To determine the frequency of a reversion mutation that allows bacterial colonies to grow in absence of vital nutrients
d. to measure rate of induced recombination in mutagen-treated fungi
e. to measure phenotypic changes is Drosophila

Answer 8

c. ​To determine the frequency of a reversion mutation that allows bacterial colonies to grow in absence of vital nutrients

Question 9

In mammalian cytogenic assays, chromosomal aberrations are measured after treatment of the cells at which sensitive phase of the cell cycle?

a. interphase
b. M phase
c. S phase
d. G1
e. G2

Answer 9

c. S phase

Question 10

Which of the following molecules is used to gauge the amount of a specific gene being transcribed to mRNA?

a. protein
b. mRNA
c. DNA
d. cDNA

e CGH

Answer 10

d. cDNA