3.20 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, and genotype

Dominant: a characteristic that will show up in offspring if the allele is present on one OR both chromosomes in a pair. A dominant allele is always shown in capital letters, for example, "AA".

Recessive: a characteristic that will only show up if the allele is present on both chromosomes in a pair. If there is only one recessive present, the characteristics of the dominant will show up. A recessive allele is shown with lowercase letters, for example. "bb"

Homozygous: if you are homozygous, you have inherited two of the same alleles. For example, "AA" or "bb". They are homozygous dominant and homozygous recessive respectively.

Heterozygous: if you are heterozygous, two of the alleles you inherited are different. For example "Ab".

Genotype: describes the alleles that a cell/organism has for a particular characteristic. It is the allele configuration that you have inherited.

Phenotype: physical characteristics that respond to the genotype.

Codominance: neither allele is dominant over the other, and neither allele is recessive so they both contribute to the characteristics of the offspring. For example, if blood group A is dominant and so is blood group B, you inherit blood group AB.