Punnett Square Review worksheet for genetics practice.

Let’s solve each Punnett square step by step.

We are told:
- Green (G) is dominant → so GG or Gg = green pod color
- Yellow (g) is recessive → only gg = yellow pod color

We’ll go row by row, left to right.

---

Top Left Square:

Parents: G and g on top; G and g on side → this is a cross between two heterozygous parents: Gg × Gg

Punnett Square:

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

Genotypes:
- GG: 1 out of 4 → ¼ = 25%
- Gg: 2 out of 4 → ½ = 50%
- gg: 1 out of 4 → ¼ = 25%

Phenotypes:
- Green (GG + Gg): 3 out of 4 → ¾ = 75%
- Yellow (gg): 1 out of 4 → ¼ = 25%

---

Top Middle Square:

Parents: G and G on top; G and g on side → GG × Gg

Punnett Square:

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

Genotypes:
- GG: 2 out of 4 → ½ = 50%
- Gg: 2 out of 4 → ½ = 50%
- gg: 0 → 0%

Phenotypes:
- All have at least one G → all green → 4/4 = 100% green
- Yellow: 0%

---

Top Right Square:

Parents: G and G on top; g and g on side → GG × gg

Punnett Square:

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

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

Phenotypes:
- All Gg → all green → 100% green
- Yellow: 0%

---

Bottom Left Square:

Parents: G and g on top; G and g on side → same as top left: Gg × Gg

Wait — let’s check the grid:

Actually, looking at the layout:

Left column has “G” and “g” on the side? Wait — no, in bottom left, it shows:

Side: G and g
Top: G and g → again Gg × Gg

Same as top left.

But wait — let me double-check the image structure from your description.

Actually, based on standard worksheet layout, and since you said “pick letters: [Green: G] [Yellow: g]”, and the squares are drawn with alleles on top and side...

Looking again:

In bottom left, it says:

Side: G and g
Top: G and g → yes, same as top left → Gg × Gg

So same result:

Genotypes: ¼ GG, ½ Gg, ¼ gg → 25%, 50%, 25%

Phenotypes: ¾ green (75%), ¼ yellow (25%)

BUT — wait! Let me look again at how the squares are labeled.

Actually, in the original problem, the bottom row might be different.

Wait — user wrote:

“Complete the Punnett Squares below...”

And listed 6 squares: 3 on top, 3 on bottom.

From text description:

Top row:

First square: side G,g ; top G,g → Gg x Gg

Second: side G,g ; top G,G → Gg x GG

Third: side g,g ; top G,G → gg x GG

Bottom row:

Fourth: side G,g ; top G,g → Gg x Gg (same as first)

Fifth: side g,g ; top G,g → gg x Gg

Sixth: side g,g ; top g,g → gg x gg

Ah! I think I misread earlier.

Let me reassign correctly based on typical worksheet layout and allele positions.

Assume for each square:

- Top row of alleles = father’s gametes
- Side column = mother’s gametes

But actually, in Punnett squares, it doesn’t matter which is which — just combine them.

Let’s label each square clearly:

---

✔ Square 1 (top left):
Top: G, g
Side: G, g
→ Cross: Gg × Gg

Offspring:
- GG, Gg
- Gg, gg

Genotypes: 1 GG : 2 Gg : 1 gg → 25% GG, 50% Gg, 25% gg
Phenotype: 75% green (GG+Gg), 25% yellow (gg)

---

✔ Square 2 (top middle):
Top: G, G
Side: G, g
→ Cross: GG × Gg

Offspring:
- GG, GG
- Gg, Gg

Genotypes: 2 GG, 2 Gg → 50% GG, 50% Gg, 0% gg
Phenotype: 100% green (all have G), 0% yellow

---

✔ Square 3 (top right):
Top: G, G
Side: g, g
→ Cross: GG × gg

Offspring:
- Gg, Gg
- Gg, Gg

Genotypes: 100% Gg
Phenotype: 100% green, 0% yellow

---

✔ Square 4 (bottom left):
Top: G, g
Side: G, g
→ Same as Square 1: Gg × Gg

Genotypes: 25% GG, 50% Gg, 25% gg
Phenotype: 75% green, 25% yellow

Wait — but in the user’s text, under bottom left, it says:

“G g” on top? And side “G” and “g”? Yes — same as top left.

But let’s check the fifth and sixth.

---

✔ Square 5 (bottom middle):
Top: G, g
Side: g, g
→ Cross: Gg × gg

Punnett:

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

Genotypes:
- Gg: 2 out of 4 → 50%
- gg: 2 out of 4 → 50%
- GG: 0%

Phenotypes:
- Green (Gg): 50%
- Yellow (gg): 50%

---

✔ Square 6 (bottom right):
Top: g, g
Side: g, g
→ Cross: gg × gg

All offspring: gg

Genotypes: 100% gg
Phenotype: 100% yellow, 0% green

---

Now, let’s write answers for each square in order.

The worksheet has 6 boxes. We’ll fill each with:

For genotypes: list fractions and percentages for each genotype present.

For phenotype: list fraction and percentage for green and yellow.

But note: the worksheet says “list the Genotype and Phenotype probabilities as fractions and percentages.”

And for each square, there are blanks for:

Genotypes ___ % ___ % ___ %
(likely for GG, Gg, gg — even if zero)

Phenotype ___ % ___ %
(green, yellow)

Also, some squares may not have all three genotypes — we still report zeros if needed.

Let’s compile final answers per square.

---

Square 1 (top left): Gg × Gg

Genotypes:
GG: ¼ = 25%
Gg: ½ = 50%
gg: ¼ = 25%

Phenotype:
Green: ¾ = 75%
Yellow: ¼ = 25%

---

Square 2 (top middle): GG × Gg

Genotypes:
GG: ½ = 50%
Gg: ½ = 50%
gg: 0 = 0%

Phenotype:
Green: 1 = 100%
Yellow: 0 = 0%

---

Square 3 (top right): GG × gg

Genotypes:
GG: 0 = 0%
Gg: 1 = 100%
gg: 0 = 0%

Phenotype:
Green: 1 = 100%
Yellow: 0 = 0%

---

Square 4 (bottom left): Gg × Gg ← same as Square 1

Genotypes:
GG: ¼ = 25%
Gg: ½ = 50%
gg: ¼ = 25%

Phenotype:
Green: ¾ = 75%
Yellow: ¼ = 25%

---

Square 5 (bottom middle): Gg × gg

Genotypes:
GG: 0 = 0%
Gg: ½ = 50%
gg: ½ = 50%

Phenotype:
Green: ½ = 50%
Yellow: ½ = 50%

---

Square 6 (bottom right): gg × gg

Genotypes:
GG: 0 = 0%
Gg: 0 = 0%
gg: 1 = 100%

Phenotype:
Green: 0 = 0%
Yellow: 1 = 100%

---

Now, to present in the format the worksheet expects.

Each square has:

Genotypes ___ % ___ % ___ %
(probably meant for GG, Gg, gg in that order)

Phenotype ___ % ___ %
(green, yellow)

So for each:

---

Top Left:

Genotypes: 25% 50% 25%
Phenotype: 75% 25%

Top Middle:

Genotypes: 50% 50% 0%
Phenotype: 100% 0%

Top Right:

Genotypes: 0% 100% 0%
Phenotype: 100% 0%

Bottom Left:

Genotypes: 25% 50% 25%
Phenotype: 75% 25%

Bottom Middle:

Genotypes: 0% 50% 50%
Phenotype: 50% 50%

Bottom Right:

Genotypes: 0% 0% 100%
Phenotype: 0% 100%

---

Final Answer:

Top Left:
Genotypes: 25% 50% 25%
Phenotype: 75% 25%

Top Middle:
Genotypes: 50% 50% 0%
Phenotype: 100% 0%

Top Right:
Genotypes: 0% 100% 0%
Phenotype: 100% 0%

Bottom Left:
Genotypes: 25% 50% 25%
Phenotype: 75% 25%

Bottom Middle:
Genotypes: 0% 50% 50%
Phenotype: 50% 50%

Bottom Right:
Genotypes: 0% 0% 100%
Phenotype: 0% 100%