Question

1. A common DNA modification cause by UV light is:

a. Formation of an alfatoxin B addition.

b. Formation of a pyrmidine dimer

c. Formation of a Thymidine glycol

d. Removal of a purine base from the DNA.

e. Conversion of a Glycine to Threonine.

2. Liver extract is added to the Ames test because

a. The liver extract provides a necessary nutrient for survival of the test bacteria.

b. The liver extract provides DNA repair mechanisms for the bacteria.

c. The liver extract opens pores on the bacteria to facilitate entry of the sample.

d. The liver extract provides RNA to activate bacterial DNA repair enzymes.

e. The liver extract may activate or deactivate a sample’s mutagenic ability.

3. DNA repairs the daughter strand if an error occurs during replication because:

a. The parent strand deletes Cytosine residues but the daughter strand does not.

b. The parent strand amplifies all CGG repeats while the daughter strand does not.

c. The parent DNA strand contains methyl-Cytosine but the daughter strand does not.

d. HIstones surrounding the replication error become heavily acetylated on the daughter strand.

e. DNA photolyase is only associated with daughter strands.

4. A gene that when inappropriately activated promotes the formation of a cancer is referred to as a(n)

a. Tumor suppressor gene

b. Cancerphobic gene

c. Oncogene

d. Anticipated gene

e. Feral gene

Answer 1

1. b. Formation of a pyrmidine dimer. Thymine base pairs next to each other in genetic sequences bond together to form pyrimidine dimers.

2. e. The liver extract may activate or deactivate a sample’s mutagenic ability. Liver extract contains enzymes that may be necessary for certain mutagens to work.

3. b. The parent DNA strand contains methyl-Cytosine but the daughter strand does not. DNA polymerase removes the incorrectly-incorporated bases from the newly-synthesized, non-methylated strand.

4. c. Oncogene It can be activated by mutation of proto-oncogene and can cause cancer.