AP BIOLOGY

Detailed explanation-1: -Only individuals with an aa genotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait.

Detailed explanation-2: -Offspring whose genotype is either AA or Aa will have the dominant trait expressed phenotypically, while aa individuals express the recessive trait.

Detailed explanation-3: -A heterozygous individual has two different alleles. Therefore it would have the genotype Aa. An individual with the genotype Aa can make two types of gametes: A and a. Since this is a random process, the individual will, on average, make equal numbers of each gamete.

Detailed explanation-4: -The genotype aa would result in an individual with the recessive phenotype. aa is a homozygous genotype that consists of two recessive alleles. There is no dominant allele present in this genotype to overrule the effect of recessive alleles. Aa is a heterozygous genotype.

Detailed explanation-5: -If the dominant allele is labeled as “A” and the recessive allele, “a”, three different genotypes are possible: “AA”, “aa”, and “Aa”. The term “homozygous” is used to describe the pairs “AA” and “aa” because the alleles in the pair are the same, i.e. both dominant or both recessive.