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.

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

(1 point)
Responses

75%
75%

0%
0%

25%
25%

50%

Answer 1

To determine the percentage of tall offspring when a heterozygous tall pea plant (Tt) is crossed with a homozygous recessive short pea plant (tt), we can use a Punnett square.

1. **Set Up the Punnett Square**:
- Parent 1 (heterozygous tall): Tt
- Parent 2 (homozygous short): tt

The possible gametes from each parent are:
- Parent 1 can produce gametes: T or t
- Parent 2 can only produce gametes: t

Now, we set up the Punnett square:

```
t t
__________
| | |
T | Tt | Tt |
| | |
| | |
t | tt | tt |
| | |
```

2. **Analyze the Results**:
From the Punnett square, we see the following combinations:
- Tt (tall)
- Tt (tall)
- tt (short)
- tt (short)

3. **Count the Phenotypes**:
- Tall (Tt): 2 out of 4 (50%)
- Short (tt): 2 out of 4 (50%)

4. **Calculate the Percentage of Tall Offspring**:
To find the percentage of tall plants, we take the number of tall offspring over the total number of offspring:

\[
\text{Percentage of tall offspring} = \frac{2}{4} \times 100 = 50\%
\]

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