Exam 7: Anatomy and Function of a Gene: Dissection Through Mutation

A bacterial mismatch repair system is able to correct replication errors that insert an incorrect nucleotide.How is this repair system able to determine which mismatched base is incorrect?

Luria and Delbruck grew many liquid cultures of bacteria then spread a small sample of each culture on nutrient agar infused with bacteriophage in separate petri plates. They assayed the number of bacterial colonies that formed on each plate. -In the Luria Delbruck experiment, what did the appearance of a bacterial colony on a petri plate indicate?

Experiment 2 depends on recombination.

Consider the pathway for the synthesis of the amino acid arginine in Neurospora: ARG-E ARG-F ARG-H ornithine \rightarrow citrulline \rightarrow argininosuccinate \rightarrow arginine Mutant strains of Neurospora may carry one or more mutations.Neurospora mutant strain b is grown on minimal media plus supplements as shown.Growth is shown by (+)and no growth is shown by (o). $~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\underline{ Supplements }$ mutant strain nothing ornithine citrulline arginino- succinate arginine a 0 0 0 + + b 0 0 + + + What can you conclude from these data?

In the human genetic disorder alkaptonuria, urine turns black because of the presence of homogentisic acid in individuals with the trait.This is due to

The base analog 5-bromouracil can tautomerize.One tautomer behaves like thymine and the other behaves like cytosine.If 5-bromouracil is used as a mutagen, what is the minimum number of times replication must occur to mutate the codon for proline (CCC)into the codon for serine (TCC)?

If a man has one premutation allele for fragile X syndrome, what is the probability that he will pass the premutation allele on to his son?

Luria and Delbruck grew many liquid cultures of bacteria then spread a small sample of each culture on nutrient agar infused with bacteriophage in separate petri plates. They assayed the number of bacterial colonies that formed on each plate. -A researcher planned to duplicate the Luria Delbruck fluctuation experiment.This researcher inoculated twenty samples of liquid nutrient media with bacteria from the same colony and let them grow overnight.The next morning the researcher noticed that all but one of the flasks had come open and were ruined.Not wishing to redo the experiment, the researcher spread samples of bacteria from the one intact liquid culture on twenty petri plates that had nutrient agar infused with bacteriophage.What results do you expect the researcher obtained from this experiment?

How is the Ames test for mutagenicity useful for identifying potential carcinogens?

In the Ames test for mutagenicity,

Intercalating agents, such as acridine orange, are mutagens because they

A plaque is

Which interaction is not involved in maintaining tertiary structure in protein molecules?

The heritable disorder fragile X syndrome, a major cause of intellectual disability, is caused by

One strain of rII- phage has a deletion in the rII region, another has a point mutation in the rII region.When E.coli K(λ)cells are infected with either rII- phage (not both)no plaques form.When E.coli K(λ)cells are infected with both rII- phage simultaneously plaques do form.Why do plaques form when E.coli K(λ)cells are infected with both types of rII- phage simultaneously?

The genetic condition xeroderma pigmentosum, which can lead to skin cancer, results from the inability to

Fruit flies normally have red eyes.Seven different true-breeding strains of fly with white eyes have been identified (A-H).In each strain, the white eye trait is due to an autosomal recessive allele.It is possible that all seven strains have mutations in the same gene.Alternatively, some or all of the strains may have mutations in different genes.To determine how many genes are involved in eye color in these flies, all possible pairwise crosses are performed.The offspring phenotypes resulting from each cross are observed.(+ = wild-type; ? = mutant) - - + + - + + - - + + - + + - - - + + + + - + + + + - + + - - - + - + - -Which strains' mutations represent a complementation group?

Which statement about sickle cell anemia is false?

What is true about the mutations within a complementation group?

Assume that the mutation rate for a given gene is 5 × 10⁻⁶ mutations per generation.For that gene, how many mutations would be expected if 10 million sperm are examined?