Exam 11: Gene Mutation, Dna Repair, and Homologous Recombination

You are interested in studying the function of a gene, so you decide to create point mutations to help you identif important residues in the encoded protein. In the following set of triplet codons, two nucleotides are underlined, which nucleotide should be mutated to ach your goal and why? $\text { 5'-ATG CC\underline{C} TGG \underline{A}AC CTG-3' }$

Which of the following statements is true of non- homologous end joining (NHEJ)?

What term describes a gene or region of a genome where mutations occur much more often than average?

Retrotransposons are unique among transposable elements in that they require the enzyme___________for mobilization?

You accidentally exposed your cell culture dish to radiation, but you are not sure of the precise wavelength of the exposure. How can you use the induced DNA damage to tell whether the radiation was UV or higher energy? What is the difference between the DNA damage caused by UV radiation compared to higher- energy radiation? Which type of damage is likely to be the most lethal to your cells?

Double- strand breaks cause genomic instability and are thus potentially lethal to cells. They also greatly increase the risk of cancer and the chance of chromosome structural mutations. Compare and contrast the two mechanisms of double- strand break repair. Why would one mechanism be used over another?

You would like to induce a transversion mutation into a sequence of DNA. Which type of chemical mutagen would give you the best chance of inducing the correct mutation without causing transition mutations as well?

Given the sequence of triplet codons: 5'- TAC AAA ATA CAG CGG- 3', which of these sequences represents a missense mutation?

Which type of mutagen has a structure similar to one of the DNA nucleotides and therefore can work its way into DNA, where it pairs with a nucleotide?

Describe a hypothetical result of the fluctuation test that would have supported the hypothesis that mutations occur in response to environmental challenge, and explain how this result was different from the observed result described in the chapter?

What are three genes that are usually encoded by retrotransposons?

Which type of mutation converts a nucleotide to an alternative structure with the same composition but a slightly different placement of rare, less stable hydrogen bonds that cause base- pair mismatch?

Agents generating mutation- inducing DNA damage are collectively referred to as_________ .

What type of mutation is seen here? Wild type:5'- TAC AAA ATA CAG CGG- 3' Mutation: 5'- TAC AAG ATA CAG CGG- 3'

Which type of mutation is possible due to the redundant nature of the genetic code?

You use several model organisms in your lab's research. Which of your model organisms would you expect to exhibit a higher mutation frequency: E. coli, D. melanogaster, or M. musculus?

Which bases would you mutate to create a nonsense transition mutation? 5'- ATG GGA TGG CAC CTG- 3'

What are the two basic types of base- pair substitutions?

_________are structures that have the same composition and general arrangement but a slight difference in bonding and placement of a hydrogen.

If you have screened 100,000 pollen grains and identified 5 mutants, what is the mutation frequency?