You are studying mutations in a bacterial gene that codes for an enzyme whose amino acid sequence is known. in the wild-type protein, proline is the fifth amino acid from the amino terminal end. in one of your mutants with nonfunctional enzyme, you find a serine at position number 5. you subject this mutant to further mutagenesis and recover three different strains. strain a has a proline at position number 5 and acts just like wild type. strain b has tryptophan at position number 5 and also acts like wild type. strain c has no detectable enzyme function at any temperature, and you can't recover any protein that resembles the enzyme. you mutagenize strain c and recover a strain (c-1) that has enzyme function. the second mutation in c-1 responsible for the recovery of enzyme function does not map at the enzyme locus. a. what is the nucleotide sequence in both strands of the wild-type gene at this location? b. why does strain b have a wild-type phenotype? why does the original mutant with serine at position 5 lack function? c. what is the nature of the mutation in strain c? d. what is the second mutation that arose in c-1?

Acertain species of fish can have either long or short fins. the allele for long fins is dominant over the allele for short fins. a heterozygous, long-finned fish is crossed with a homozygous, short-finned fish. of the offspring, will have long fins and be , and will have short fins and be .

In a hypothetical breed of dogs, coat color is controlled by two genes. there are six different coat colors in this breed: black, brown, cream, gray, silver, and tan. consider the following crosses. cross 1: black females from a lineage of all black dogs are crossed with brown males from a lineage of all brown dogs. f1 males and females are all black. when f1 are intercrossed, f2 males and females are black or brown. cross 2: black females from a lineage of all black dogs are crossed with tan males from a lineage where all males are tan and all females are cream. f1 males are black, f1 females are gray. when f1 are intercrossed, f2 males and females are black, brown, gray, or tan. cross 3: silver females from a lineage where all females are silver and all males are gray are crossed with brown males from a lineage of all brown dogs. f1 males and females are all gray. when f1 are intercrossed, f2 males are black, brown, gray, or tan, f2 females are cream, gray, silver, or tan. select the correct statements regarding the mode of inheritance of the coat color genes. a) both genes are x-linked. b) both genes are autosomal. c) one of the genes modifies the expression of the other gene. d) each gene has an additive effect on the intensity of coat color. e) each gene independently specifies three colors. f) one of the genes is autosomal, and the other is x-linked.

Consider the following reaction: 2h2 + o2 —> 2h2o a) what are the reactants in this reaction? b) what are the products in this reaction? c) how many molecules of oxygen are used in this reaction?