Wild type blue-eyed mary has blue flowers. two genes control the pathway that makes the blue pigment: the product of gene w turns a white precursor into magenta pigment. the product of gene m turns the magenta pigment into blue pigment. each gene has a recessive loss-of-function allele: w and m, respectively. a dihybrid (wwmm) is self-pollinated. what proportion of the offspring will be magenta?

3/8

Explanation:

Two genes are involved in the determination of flower color, W/w and M/m.

The W allele uses the white pigment as a substrate to produce the magenta pigment, and the M allele uses magenta to produce blue pigment.

The recessive alleles w and m produce a non-functional protein, so the white and magenta pigments can't be transformed into their respective products if the genotype is homozygous recessive.

Please see the first attachment for a representation of the flower color pathway.

We have different genotype possibilities:      

To analyze the offspring of a dihybrid cross, we need to do the Punnett Square (see second attachment).

The genotypes that determine the magenta color are WWmm and Wwmm.

From the Punnett Square, we can see that 3/8 individuals of the offspring will be W_mm and therefore magenta.

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.