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.

Question

(HINT: use a Punnett square to help you with this question)

(1 point)
Responses

25%
25%

0%
0%

50%
50%

75%

Answer 1

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

1. Parent Genotypes:

   • Parent 1 (heterozygous tall): Tt
   • Parent 2 (homozygous recessive short): tt

2. Possible Gametes from each parent:

   • Parent 1 can produce gametes: T or t
   • Parent 2 can produce gametes: t or t

3. Punnett Square:

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

4. Offspring Genotypes:

   • Tt (tall): 2 squares
   • tt (short): 2 squares

5. Percentage Calculation:

   • Total offspring: 4 (2 Tt + 2 tt)
   • Tall offspring (Tt): 2 out of 4

Thus, the percentage of tall offspring is: \[ \frac{2}{4} \times 100 = 50% \]

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