Question

in pea plants t is the allele for tall plants while t is the allele for dwarf plants. If you have a tall plant, demonstrate with a testcross how it could be determained if the plant is homozygous tall or heterozygous tall.

Answer 1

To determine if a tall pea plant is homozygous tall or heterozygous tall, a testcross can be performed by crossing the tall plant with a dwarf plant.

Step-by-step explanation:

In pea plants, the allele for tall plants is represented by uppercase letter T, while the allele for dwarf plants is represented by lowercase letter t. To determine if a tall plant is homozygous tall or heterozygous tall, you can perform a testcross by crossing the tall plant with a dwarf plant. If the tall plant is homozygous tall (TT), all the offspring will be tall. If the tall plant is heterozygous tall (Tt), half of the offspring will be tall and half will be dwarf.

Answer 2

The tall plant is homozygous (TT) if all the progeny of the test cross is "tall". Presence of both tall and short progeny makes the "tall" plant heterozygous (Tt).

Step-by-step explanation:

The "tall" plant with unknown genotype would be crossed with a homozygous short plant (tt) of the same species. This is called the testcross. If the progeny of test cross includes both tall and short plants, the "tall" plant with unknown genotype was heterozygous for the gene. On the other hand, the presence of only tall progeny in the testcross reflects the fact that the "tall" plant with unknown genotype was homozygous for the allele for "tallness".