AP BIOLOGY

Detailed explanation-1: -Aa-heterozygous dominant (individual has both dominant and recessive gene, but only one is expressed)

Detailed explanation-2: -That can be either AA or aa, homozygous dominant or homozygous recessive. An individual who is homozygous dominant for a particular gene will have two dominant “A” alleles for that gene. An individual who is homozygous recessive will have the “aa” genotype, two recessive “a” alleles.

Detailed explanation-3: -An organism with two dominant alleles for a trait is said to have a homozygous dominant genotype. Using the eye color example, this genotype is written BB. An organism with one dominant allele and one recessive allele is said to have a heterozygous genotype. In our example, this genotype is written Bb.

Detailed explanation-4: -A dominant allele is denoted by a capital letter (A versus a). Since each parent provides one allele, the possible combinations are: AA, Aa, and aa. Offspring whose genotype is either AA or Aa will have the dominant trait expressed phenotypically, while aa individuals express the recessive trait.

Detailed explanation-5: -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).