A male college student comes to you with what he describes as “strange symptoms”. He says his joints hurt, simple cuts seem to take a long time to heal, and his gums bleed easily, even when he is just eating. His teeth feel loose- he asks you if he is imagining that. He feels like he gets sick more often than his friends do. An examination shows some little pinpoint hemorrhages under his skin, like bright red freckles. This young man hates fruits and vegetables. What vitamin is he deficient in? What is the toxic level?

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.

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.