Punnett Squares | Worksheet - Free Printable

Here is the step-by-step solution to the problems on the worksheet.

Part 1: Round vs. Wrinkled Seeds

Understanding the Alleles:
* R = Dominant allele for Round seeds.
* r = Recessive allele for Wrinkled seeds.
* Heterozygous means having two different alleles (one dominant, one recessive). So, a heterozygous plant has the genotype Rr.

The problem asks us to look at a cross between two parents who are both heterozygous (Rr x Rr).

a. How many boxes represent offspring that are homozygous for round seed shape?
* "Homozygous" means having two of the same alleles.
* "Round" is the dominant trait, represented by R.
* Therefore, "homozygous for round" means the genotype must be RR.
* Looking at the Punnett square provided in section a:
* Top-Left box: RR
* Top-Right box: Rr
* Bottom-Left box: Rr
* Bottom-Right box: rr
* Only the top-left box contains RR.

b. How many boxes represent offspring that are heterozygous for the seed shape?
* "Heterozygous" means having different alleles (Rr).
* Looking at the Punnett square in section a:
* Top-Right box: Rr
* Bottom-Left box: Rr
* There are two boxes with this genotype.

c. Shade in the boxes that represent offspring with round seeds.
* An offspring will have round seeds if it has at least one dominant R allele.
* Let's check each box in section a:
* RR: Has dominant R. Phenotype is Round.
* Rr: Has dominant R. Phenotype is Round.
* Rr: Has dominant R. Phenotype is Round.
* rr: No dominant R. Phenotype is Wrinkled.
* Therefore, you should shade the RR, Rr, and Rr boxes.

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Part 2: Purple vs. White Flowers

Understanding the Alleles:
* F = Dominant allele for Purple flowers.
* f = Recessive allele for White flowers.
* The parents are both heterozygous, meaning their genotype is Ff.

Completing the Punnett Square:
To fill in the empty boxes, we combine the letter from the top column with the letter from the side row.

1. Top-Left Box: Column F + Row F = FF
2. Top-Right Box: Column f + Row F = Ff (Usually written with the capital letter first)
3. Bottom-Left Box: Column F + Row f = Ff
4. Bottom-Right Box: Column f + Row f = ff

Filled Grid:
| | F | f |
| :--- | :---: | :---: |
| F | FF | Ff |
| f | Ff | ff |

──────────────────────────────────────

Final Answer:

Part 1 (Seeds):
a. 1
b. 2
c. You should shade in the following three boxes:
1. The box with RR
2. The box with Rr (top right)
3. The box with Rr (bottom left)
*(Do not shade the box with rr)*

Part 2 (Flowers):
The completed Punnett square boxes are:
* Top Left: FF
* Top Right: Ff
* Bottom Left: Ff
* Bottom Right: ff