A tall, heterozygous pea plant is cross-pollinated with another tall, heterozygous pea plant. Use a Punnett square to determine the probability that the offspring is a tall, homozygous pea plant.

Question

a. 25%

b. 50%

c. 0%

d. 75%

Answer 1

To determine the probability of obtaining a tall, homozygous pea plant from a cross between two tall, heterozygous pea plants, let's first define the genotypes:

• Tall (dominant): T
• Short (recessive): t

Since both parent plants are heterozygous tall, their genotypes can be represented as Tt.

Now, we can set up a Punnett square:

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

From the Punnett square, we can see the possible genotypes of the offspring:

• TT (homozygous tall) = 1
• Tt (heterozygous tall) = 2
• tt (homozygous short) = 1

Now, let's summarize the results:

• TT: 1 (25%)
• Tt: 2 (50%)
• tt: 1 (25%)

To answer the question specifically about the probability of getting a tall, homozygous pea plant (TT), we see there is 1 out of 4 squares representing TT.

Thus, the probability that the offspring is a tall, homozygous pea plant is 25%.

The answer is a. 25%.