9 Hands-On Worksheet Punnett Square Worksheet - The Teach Simple Blog - Free Printable

Problem Overview:

The task involves using Punnett squares to determine the possible offspring genotypes and phenotypes for different parent combinations. The alleles are defined as follows:
- T: Dominant allele for tall plants
- t: Recessive allele for short plants

The Punnett squares provided in the image represent four different parent combinations. We need to fill in the Punnett squares and determine the possible offspring genotypes and their expected ratios.

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Step-by-Step Solution:

#### 1. Both Parents Are Dominant Tall (TT × TT)

- Parents: TT (dominant tall) × TT (dominant tall)
- Punnett Square:
```
T T
T TT TT
T TT TT
```

- Offspring Genotypes: All offspring will have the genotype TT.
- Phenotypes: Since TT is dominant tall, all offspring will be tall.

- Answer:
1. TT
2. TT
3. TT
4. TT

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#### 2. Both Parents Are Mixed Hybrids (Tt × Tt)

- Parents: Tt (mixed hybrid) × Tt (mixed hybrid)
- Punnett Square:
```
T t
T TT Tt
t Tt tt
```

- Offspring Genotypes:
- TT (25%)
- Tt (50%)
- tt (25%)

- Phenotypes:
- TT and Tt: Tall (75%)
- tt: Short (25%)

- Answer:
1. TT
2. Tt
3. Tt
4. tt

Expected Ratio: 3 Tall : 1 Short

---

#### 3. One Parent Is Dominant Tall, One Is Mixed Hybrid (TT × Tt)

- Parents: TT (dominant tall) × Tt (mixed hybrid)
- Punnett Square:
```
T t
T TT Tt
T TT Tt
```

- Offspring Genotypes:
- TT (50%)
- Tt (50%)

- Phenotypes:
- TT and Tt: Tall (100%)

- Answer:
1. TT
2. TT
3. Tt
4. Tt

Expected Ratio: All Tall

---

#### 4. Both Parents Are Recessive Short (tt × tt)

- Parents: tt (recessive short) × tt (recessive short)
- Punnett Square:
```
t t
t tt tt
t tt tt
```

- Offspring Genotypes: All offspring will have the genotype tt.
- Phenotypes: Since tt is recessive short, all offspring will be short.

- Answer:
1. tt
2. tt
3. tt
4. tt

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Final Answers:

1. Both parents are dominant tall (TT × TT):
- Offspring: TT, TT, TT, TT
- Phenotype: All tall

2. Both parents are mixed hybrids (Tt × Tt):
- Offspring: TT, Tt, Tt, tt
- Expected ratio: 3 Tall : 1 Short

3. One parent is dominant tall, one is mixed hybrid (TT × Tt):
- Offspring: TT, TT, Tt, Tt
- Expected ratio: All Tall

4. Both parents are recessive short (tt × tt):
- Offspring: tt, tt, tt, tt
- Phenotype: All short

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Boxed Final Answer:

\[
\boxed{
\begin{array}{l}
\text{1. } \text{TT, TT, TT, TT} \\
\text{2. } \text{TT, Tt, Tt, tt} \quad (\text{3 Tall : 1 Short}) \\
\text{3. } \text{TT, TT, Tt, Tt} \quad (\text{All Tall}) \\
\text{4. } \text{tt, tt, tt, tt} \quad (\text{All short})
\end{array}
}
\]