An allosteric enzyme differs from a Michaelis-Menten enzyme because the allosteric enzyme:

Because an allosteric enzyme has multiple active sites

Explanation:

an allosteric enzyme has multiple active sites because it cause a modification binding of an allosteric effector at a certain site which is not the active site. It has multiple active site in which the binding of an active site can affect it's affinity with other active site.

The alleles of a plant that is heterozygous for seed color can be represented as Y for dominant allele for yellow seed and y for recessive allele for green seed.

Explanation: A plant that is heterozygous for seed colour has one dominant allele and one recessive allele for seed colour. If Y represents the dominant allele for yellow seed colour and y represents the recessive allele for green seed colour, therefore the plant has a genotype of Yy. A dominant allele is one that has the ability to mask the effect of a recessive allele while a recessive allele is one whose effect is masked by a dominant allele. Dominant alleles are denoted with upper cases while recessive alleles are denoted with lower cases. A plant that is heterozygous for seed colour with genotype Yy will manifest outwardly as Yellow seed colour due to the presence of the dominant allele Y.