Worksheet for practicing Punnett squares and determining genotypic and phenotypic ratios in genetics.

You’re working on a Punnett Square Review worksheet focused on pea plant pod color, where:

- Green (G) is the dominant trait
- Yellow (g) is the recessive trait

You are to complete 6 Punnett Squares, then calculate and express the genotype and phenotype probabilities as fractions and percentages.

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Let’s solve each Punnett Square one by one.

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🔹 Square 1: Gg × Gg

```
| G | g
------|-------|-------
G | GG | Gg
------|-------|-------
g | Gg | gg
```

✔ Genotypes:
- GG → 1/4 → 25%
- Gg → 2/4 = 1/2 → 50%
- gg → 1/4 → 25%

✔ Phenotypes:
- Green (GG or Gg) → 3/4 → 75%
- Yellow (gg) → 1/4 → 25%

---

🔹 Square 2: GG × Gg

```
| G | g
------|-------|-------
G | GG | Gg
------|-------|-------
G | GG | Gg
```

✔ Genotypes:
- GG → 2/4 = 1/2 → 50%
- Gg → 2/4 = 1/2 → 50%
- gg → 0/4 → 0%

✔ Phenotypes:
- Green → 4/4 = 1 → 100%
- Yellow → 0/4 → 0%

---

🔹 Square 3: gg × gg

```
| g | g
------|-------|-------
g | gg | gg
------|-------|-------
g | gg | gg
```

✔ Genotypes:
- gg → 4/4 = 1 → 100%
- GG → 0%, Gg → 0%

✔ Phenotypes:
- Yellow → 4/4 = 1 → 100%
- Green → 0%

---

🔹 Square 4: GG × gg

```
| g | g
------|-------|-------
G | Gg | Gg
------|-------|-------
G | Gg | Gg
```

✔ Genotypes:
- Gg → 4/4 = 1 → 100%
- GG → 0%, gg → 0%

✔ Phenotypes:
- Green → 4/4 = 1 → 100%
- Yellow → 0%

---

🔹 Square 5: Gg × gg

```
| g | g
------|-------|-------
G | Gg | Gg
------|-------|-------
g | gg | gg
```

✔ Genotypes:
- Gg → 2/4 = 1/2 → 50%
- gg → 2/4 = 1/2 → 50%
- GG → 0%

✔ Phenotypes:
- Green (Gg) → 2/4 = 1/2 → 50%
- Yellow (gg) → 2/4 = 1/2 → 50%

---

🔹 Square 6: Gg × Gg *(Same as Square 1)*

This is identical to Square 1.

✔ Genotypes:
- GG → 1/4 → 25%
- Gg → 2/4 = 1/2 → 50%
- gg → 1/4 → 25%

✔ Phenotypes:
- Green → 3/4 → 75%
- Yellow → 1/4 → 25%

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## ✔ Final Answers to Fill In:

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Top Row (Left to Right):

#### First Square (Gg x Gg):
- Genotypes:
- GG → 1/4 → 25%
- Gg → 1/2 → 50%
- gg → 1/4 → 25%
- Phenotypes:
- Green → 3/4 → 75%
- Yellow → 1/4 → 25%

#### Second Square (GG x Gg):
- Genotypes:
- GG → 1/2 → 50%
- Gg → 1/2 → 50%
- gg → 0%
- Phenotypes:
- Green → 1 → 100%
- Yellow → 0%

#### Third Square (gg x gg):
- Genotypes:
- gg → 1 → 100%
- GG → 0%, Gg → 0%
- Phenotypes:
- Yellow → 1 → 100%
- Green → 0%

---

Bottom Row (Left to Right):

#### Fourth Square (GG x gg):
- Genotypes:
- Gg → 1 → 100%
- GG → 0%, gg → 0%
- Phenotypes:
- Green → 1 → 100%
- Yellow → 0%

#### Fifth Square (Gg x gg):
- Genotypes:
- Gg → 1/2 → 50%
- gg → 1/2 → 50%
- GG → 0%
- Phenotypes:
- Green → 1/2 → 50%
- Yellow → 1/2 → 50%

#### Sixth Square (Gg x Gg):
*(Same as first square)*
- Genotypes:
- GG → 1/4 → 25%
- Gg → 1/2 → 50%
- gg → 1/4 → 25%
- Phenotypes:
- Green → 3/4 → 75%
- Yellow → 1/4 → 25%

---

## 📝 Summary Table for Easy Filling:

| Square | Cross | Genotypes | Phenotypes |
|--------|-------------|-------------------------------|--------------------------|
| 1 | Gg × Gg | GG: 1/4, Gg: 1/2, gg: 1/4 | Green: 3/4, Yellow: 1/4 |
| 2 | GG × Gg | GG: 1/2, Gg: 1/2, gg: 0 | Green: 1, Yellow: 0 |
| 3 | gg × gg | gg: 1, others: 0 | Yellow: 1, Green: 0 |
| 4 | GG × gg | Gg: 1, others: 0 | Green: 1, Yellow: 0 |
| 5 | Gg × gg | Gg: 1/2, gg: 1/2, GG: 0 | Green: 1/2, Yellow: 1/2 |
| 6 | Gg × Gg | Same as #1 | Same as #1 |

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✔ You can now confidently fill in your worksheet with these answers!

Let me know if you’d like this formatted as a printable answer key!