Exam 19: Gene Mutation and Dna Repair

A mutation in a promoter region that causes the promoter sequence to more closely resemble the consensus sequence is called an up promoter mutation and results in a decrease in transcription.

A translocation that moves a gene from an area of euchromatin to heterochromatin would typically cause a(n) ________ in the expression of the gene.

Most TNRE repeats involve expansion of which codon?

The mutation frequency would be the same for all genes in a given culture.

Which repair mechanism utilizes MutL, MutH, and MutS proteins in E. coli?

Silent mutations are possible due to the degenerate nature of the genetic code.

The complete loss of either a guanine or adenine from DNA is an example of ________.

In the following sequence of DNA, the italicized base has been mutated. What type of mutation is this? 5' - G A T C T C C G A A T T - 3' original strand 5' - G A T C T C C C A A T T - 3' mutated strand

The conversion of cytosine to uracil in DNA is an example of ________.

The most common genotype in a population is called the mutant genotype.

In the nucleotide excision repair system, which of the following proteins is responsible for recognizing a thymine dimer to be repaired?

Somatic cells are those that give rise to sperm and egg cells.

A culture of E. coli bacteria is used to establish several subcultures. Each subculture is then plated and individual colonies that grow on the agar plates are then tested for their sensitivity to the bacteriophage T1. There is a spectrum of sensitivities where some plates have a high number of resistant colonies and some plates had very few. This data supports which theory?

Which types of mutations are least likely to be subjected to natural selection?

A change in the chromosome number is called a point mutation.

There is a spectrum of syndromes in humans known as Xeroderma pigmentosum. The individuals that have XD most commonly have mutations in their nucleotide excision DNA repair mechanisms that make them particularly susceptible to environmental mutagens such as UV light. Individuals have to be careful with how much sunlight they are exposed to since they have an extremely elevated chance for developing skin cancer. There have been several cell lines that have been established from XD patients that can be studied in tissue culture. In an experiment several different cell lines of unknown origin were tested for their ability to undergo unscheduled DNA synthesis (UDS), an assay for DNA repair. In this assay the amount of radioactive nucleotides that are incorporated into DNA after the cell sustains a mutagenic event are measured. The amount of radioactivity incorporated is measured by the number of counts per minute (CPM). Below is a table from such an experiment. Which cell line is most likely from XD patient(s)?

TNRE repeats frequently result in the addition of extra histidine amino acids to the protein.

What would be a set of anticipated results from a "Lederberg" experiment?

The process of replica plating was designed to test if mutations occurred in response to a selective agent or if mutations were naturally present in the population before selection.

Mutations that change the configuration of a protein at a specific temperature are called ________ mutations.