Use the following information to answer the questions below. Skin color in a certain species of fish is inherited via a single gene with four different alleles. One fish of this type has alleles 1 and 3 (S1S3) and its mate has alleles 2 and 4 (S2S4). If each allele confers a unit of color darkness such that S1 has one unit, S2 has two units, and so on, then what proportion of their offspring would be expected to have five units of color

1/2 = 50% of the progeny is expected to have 5 units of color → S1S4 + S2S3

Explanation:

Available data:

Cross:

Parentals) S1S3    x    S2S4

Gametes) S1   S3     S2    S4

F1) 1/4 = 25% of the progeny is expected to be S1S2 → 3 units

    1/4 = 25% of the progeny is expected to be S1S4 → 5 units

     1/4 = 25% of the progeny is expected to be S2S3 → 5 units

     1/4 = 25% of the progeny is expected to be S3S4 → 7 units

1/2 = 50% of the progeny is expected to have 5 units of color → 1/4 = 25% S1S4 + 1/4 = 25% S2S3

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.