Question

In pea plants, tall plants (T) are dominant over short plants (t). If a heterozygous tall pea plant is crossed with a homozygous recessive short pea plant, what percentage of the offspring is expected to be tall?

A: 75%

B: 50%

C: 0%

D: 25%

Answer 1

To determine the percentage of tall offspring from the cross between a heterozygous tall pea plant (Tt) and a homozygous recessive short pea plant (tt), we can set up a Punnett square.

The alleles for the parents are:
- One parent (heterozygous tall): Tt
- Other parent (homozygous recessive short): tt

The possible gametes from each parent are:
- Tt can produce gametes: T and t
- tt can produce gametes: t and t

Now we can set up the Punnett square:

| | t | t |
|------|------|------|
| **T**| Tt | Tt |
| **t**| tt | tt |

From the Punnett square, we can see the genotypes of the offspring:
- 2 offspring are Tt (tall)
- 2 offspring are tt (short)

To find the percentage of tall offspring:
- Total offspring = 4
- Tall offspring (Tt) = 2

Percentage of tall offspring = (Number of tall offspring / Total offspring) * 100 = (2/4) * 100 = 50%

Therefore, the expected percentage of the offspring that is tall is **B: 50%**.