AP BIOLOGY

Detailed explanation-1: -The notation tt means the homozygous condition, wherein the homologous pair contains same alleles of a gene. Alleles are different forms of one gene.

Detailed explanation-2: -An organism can be either homozygous dominant ( TT ) or homozygous recessive ( tt ). If an organism has two different alleles ( Tt ) for a certain gene, it is known as heterozygous (hetero-means different).

Detailed explanation-3: -Complete answer: When cross takes place between Tt and tt two different types of alleles are form, Tt X tt = Tt, Tt, tt, and tt. The genotypic ratio for this cross is 1:1 and the phenotypic ratio is 1:1, where Tt is heterozygous dominant and tt is heterozygous recessive. This type of cross is a test cross.

Detailed explanation-4: -(HOH-moh-ZY-gus JEE-noh-tipe) A term that describes having two identical versions of the same gene (one inherited from the mother and one inherited from the father). In a homozygous genotype, either both genes are normal or both genes have the same mutation (change).