Final answer:
When a heterozygous tall pea plant (Tt) is crossed with a homozygous recessive (tt) pea plant, the phenotypic outcomes for their offspring are a 1 Tall: 1 Dwarf ratio. This is due to the heterozygous parent being able to pass on either the dominant or recessive allele, resulting in a 50% chance for each phenotype.
Step-by-step explanation:
Predicting Phenotypic Outcomes in Genetics
When considering the cross between a heterozygous tall pea plant (Tt) and a homozygous recessive (tt) pea plant, we aim to predict the phenotypic outcomes of their offspring. By using a Punnett square, we can visualize the possible genetic combinations. The heterozygous parent can contribute either a dominant (T) or a recessive (t) allele, while the homozygous recessive parent can only contribute a recessive (t) allele.
Setting up a Punnett square, we pair the alleles from each parent:
- Tt (heterozygous parent) can produce gametes with alleles T and t.
- tt (homozygous recessive parent) can produce gametes with alleles t only.
The resulting combinations will be:
- Tt - Tall (because of the dominant T allele)
- tt - Dwarf (since there are no dominant alleles to mask the recessive trait)
The phenotypic ratio of the offspring will be 1 Tall: 1 Dwarf, meaning that there is a 50% chance for the offspring to be tall and a 50% chance to be dwarf. This outcome occurs because the heterozygous parent has a 50% chance of passing on either allele.