The allele for blue feathers is dominant. the allele for brown feather is recessive. if one bird that is homozygous dominant is crossed with another bird that is heterozygous, what would the punnett square look like.

The following punnet square would be constructed from the above mentioned cross:

        b             b

B     Bb           Bb

B     Bb           Bb

A punnet square can be described as a diagram which is made to illustrate the outcomes of a cross.

The results from the above punnet square show that the offsprings produced from a cross between homozygous blue and brown parent, will all have blue feathers but they all will be heterozygous for the trait.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.