In peas, the allele for yellow seeds (y) is dominant to the allele for green seeds (y). what would be the genotype and phenotype ratios of offspring from a cross between yy (heterozygous) and yy (homozygous recessive) individuals?
a. genotype: ½ yy : ½ yy; phenotype: ½ yellow : ½ green
b. genotype: all yy; phenotype: all yellow
c. genotype: ½ yy : ½ yy; phenotype: all yellow
d. genotype: all yy; phenotype: all green

A. Genotype: 1/2 Yy; 1/2 yy. Phenotype: 1/2 Yellow; 1/2 Green.

Explanation: The answer lies in Punnett´s Square. A visual representation of Mendelian inheritance. Dominant genes always express when an organism presents them. Recessive genes express when both alleles contain the recessive gene. A heterozygote contains different alleles for the same gene (Yy). A homozygote contains the same alleles for the same gene (YY/yy), which can be a Dominant (YY) or Recessive (yy) Homozygote.

     y  |  y

Y  Yy | Yy

y   yy | yy

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.