17. Mutation, Repair, and Recombination

Which of the following mutagens wedges between DNA bases to disrupt the helix structure?

Which of the following mutagens alters base affinities by adding an alkyl group?

Which of the following mutations would have the least effect on an individual?

Identify two general ways chemical mutagens can alter DNA. Give examples of these two mechanisms.

How do we know that certain chemicals and wavelengths of radiation induce mutations in DNA?

Nitrous acid and 5-bromodeoxyuracil (BrdU) alter DNA by different mechanisms. What type of mutation does each compound produce?

UV irradiation causes damage to bacterial DNA. What kind of damage is frequently caused and how does photolyase repair the damage?

In March 2011 an earthquake measuring approximately 9.0 on the Richter scale struck Fukushima, Japan. Several nuclear reactors at the Fukushima Daichii Nuclear Power Plant were damaged, and nuclear core meltdown occurred. A massive release of radiation accompanied damage to the plant, and 5 years later the incidence of thyroid cancer in children exposed to the radiation was determined to be well over 100 times more frequent than expected without radiation exposure. DNA damage and mutations resulting from radiation exposure are suspected of causing this increased cancer rate. Do you think it is possible that significant increases in the incidence of other types of cancer will occur in the future among people who were exposed to the Fukushima radiation? Why?

In March 2011 an earthquake measuring approximately 9.0 on the Richter scale struck Fukushima, Japan. Several nuclear reactors at the Fukushima Daichii Nuclear Power Plant were damaged, and nuclear core meltdown occurred. A massive release of radiation accompanied damage to the plant, and 5 years later the incidence of thyroid cancer in children exposed to the radiation was determined to be well over 100 times more frequent than expected without radiation exposure. DNA damage and mutations resulting from radiation exposure are suspected of causing this increased cancer rate. What gene discussed in this chapter might be responsible for pausing the cell cycle of dividing cells long enough for radiation-induced damage to be repaired in cells?

Ultraviolet (UV) radiation is mutagenic.

Identify and describe two DNA repair mechanisms that remove UV-induced DNA lesions.

Ultraviolet (UV) radiation is mutagenic.

How do UV-induced DNA lesions lead to mutation?

Ultraviolet (UV) radiation is mutagenic.

What kind of DNA lesion does UV energy cause?

Researchers interested in studying mutation and mutation repair often induce mutations with various agents. What kinds of gene mutations are induced by

Radiation energy? Give two examples.

Researchers interested in studying mutation and mutation repair often induce mutations with various agents. What kinds of gene mutations are induced by

Chemical mutagens? Give two examples.