Exam 15: Gene Mutation, Dna Repair, and Transposition

A missense mutation causes premature chain (protein) termination.

List five general categories of mutation.

Some bacterial transposons, known as Tn elements, are larger than insertion sequences (IS elements) and contain protein-coding genes that have human health significance. What might such a bacterial transposon contain?

Mutations that arise in nature, from no particular artificial agent, are called ________.

Three major types of RNAs are mRNA, rRNA, and tRNA. For each of the conditions below predict the consequences in terms of the population of proteins being synthesized in a particular cell. What qualitative and quantitative changes, if any, are expected in the individual protein involved (if one is involved) and in the population of proteins produced in that cell? a) A frameshift mutation in mRNA. The condition is heterozygous in the involved cell. b) A deletion (homozygous) that removes approximately half of the rRNA genes.

How was it determined that X-rays are mutagenic?

Which human condition is caused by unrepaired UV-induced lesions?

Describe the mutagenic action of the following two mutagens: 5-bromouracil and ultraviolet light.

A class of mutations that results in multiple contiguous amino acid changes in proteins is likely to be which of the following?

Describe the action of the enzyme transposase.

IS (insertion sequences) elements are stable DNA occupants of prokaryotic genomes that are not found among eukaryotes.

Assume that a new mutation occurs in the germ line of an individual. What finding would suggest that the new mutation is dominant rather than recessive?

Nutritional mutations can be defined as ________.

Recombinational repair is activated when damaged DNA has escaped repair and the distortion disrupts the process of replication. Which gene is responsible recombinational repair?

A mutation that occurs naturally, without exposure to a known mutagen, is called a(n) ________.

Under which condition(s) might one have an amino acid substitution in a protein that does not result in an altered phenotype?

What are LINES?

Strand discrimination during the process of DNA repair is based on DNA methylation in E. coli.

Pyrimidine dimers are typically caused by the mutagen 2-aminopurine.

Considering the electromagnetic spectrum, identify likely mutagens from the following list: radio waves, microwaves, infrared, ultraviolet, X-rays, gamma rays, cosmic rays.