Exam 14: Gene Mutation,DNA Repair,and Transposition

DNA may be damaged from the by-products of normal cellular aerobic respiration.Name three of these electrophilic oxidants that are generally classified as reactive oxidants.

Barbara McClintock discovered mobile elements in corn by analyzing the genetic behavior of two elements,Ds and Ac.The interplay between these two elements has become one of the most interesting stories of discovery in the field of genetics.How do Ds and Ac interact?

Which of the following name two mutagens that would be classified as base analogs?

In a survey of 240,000 human births,six achondroplastic births were recorded to parents who were unaffected.Given that this form of dwarfism is caused by a fully penetrant,dominant,autosomal gene,what is the mutation rate?

Assuming one mutational event in a gene,on average,which of the following mutagens or mutational conditions would be expected to cause the most damage to a protein synthesized by such a mutagenized gene: 5-bromouracil,2-amino purine,ethylmethane sulfonate,or frameshift?

Describe the action of the enzyme transposase.

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

Apurinic sites (AP sites)involve a spontaneous loss of a(n)________ in an intact double-helix DNA molecule.

It has been found that a particular "+ —" combination of frameshift mutations in gene X gives a wild-type phenotype,whereas a "— +" combination gives a mutant phenotype,even though the sites of insertion/deletion are the same.How might these results be explained?

One type of mutation involves the replacement of a purine with a purine,whereas another causes the replacement of a pyrimidine with a purine or the reverse.What general terms are associated with these two mutational phenomena?

Nutritional mutations can be defined as ________.

When treating an organism with a mutagen,although it is possible that homozygous mutations will occur,it is more likely that most new mutations will be heterozygous or hemizygous.

A missense mutation causes premature chain (protein)termination.