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

Assume that a wild-type sequence is 5' AGCCTAC 3'.Which sequence could be produced by a transversion?

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) - - + + - + + - - + + - + + - - - + + + + - + + + + - + + - - - + - + - -Based on these crosses, how many different eye color genes are mutant in all of these strains collectively?

Assume that a series of compounds has been discovered in Neurospora.Compounds A-F appear to be intermediates in a biochemical pathway.Conversion of one intermediate to the next is controlled by enzymes that are encoded by genes.Several mutations in these genes have been identified and Neurospora strains 1-4 each contain a single mutation.Strains 1-4 are grown on minimal media supplemented with one of the compounds A-F.The ability of each strain to grow when supplemented with different compounds is shown in the table (+ = growth; o = no growth). Which biochemical pathway fits the data presented? Media supplement strain A B C D E F 1 o o o + + + 2 o o o o + + 3 o o o o + o 4 o o + + + +

In a polypeptide, what level of structure refers to a localized region that takes on a particular geometry?

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 alanine (GCC)?

Alkylating agents, such as ethylmethane sulfate (EMS), are mutagens because they

Which type of mutation is least likely to revert?

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 a is grown on minimal media plus supplements as shown.Growth is shown by (+)and no growth is shown by (o).Growing strain a cells accumulate citrulline. $~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\text { Supplements }$ mutant strain nothing ornithine citrulline arginino- succinate arginine a 0 0 0 0 + Which statement is true about strain a?

The condition sickle cell anemia is due to

Which statement(s)about the rII- strain of T4 bacteriophage that Benzer studied is (are)true? (Select all that apply. )

Red-green color blindness is more common in males than females because

Examination of the rhodopsin gene family provides evidence for gene evolution by

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. -What did the results of the Luria Delbruck fluctuation experiment indicate?

Replacing an adenine nucleotide with a guanine is an example of a

The photoreceptor protein rhodopsin

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. -When Luria and Delbruck assayed bacterial growth on the petri plates, what did they find?

Which statement about amino acids is false?

The first step in base excision repair is

Which statement about amino acids is false?

Experiment 1 depends on recombination.