Mendelian Genetics Punnett Square Worksheet - Free Printable

To solve the problems presented in the image, we will use Punnett squares to determine the genotypic and phenotypic ratios for each cross. Let's go through each problem step by step.

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Problem 1: Red Fruit vs. Yellow Fruit

#### Key:
- Red fruit is dominant over yellow fruit.
- Genotypes:
- Red fruit: \( RR \) or \( Rr \)
- Yellow fruit: \( rr \)

#### Cross:
- Parent 1: Red fruit (\( RR \))
- Parent 2: Yellow fruit (\( rr \))

#### Punnett Square:
| | \( r \) | \( r \) |
|-----|---------|---------|
| \( R \) | \( Rr \) | \( Rr \) |
| \( R \) | \( Rr \) | \( Rr \) |

#### Analysis:
- All offspring have the genotype \( Rr \).
- Since \( R \) (red) is dominant over \( r \) (yellow), all offspring will express the red phenotype.

#### Ratios:
- Genotypic Ratio: \( 0\% \) \( RR \), \( 100\% \) \( Rr \), \( 0\% \) \( rr \)
- Phenotypic Ratio: \( 100\% \) Red, \( 0\% \) Yellow

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Problem 2: Purple Flowers vs. White Flowers

#### Key:
- Purple flowers are dominant over white flowers.
- Genotypes:
- Purple flowers: \( PP \) or \( Pp \)
- White flowers: \( pp \)

#### Cross:
- Parent 1: Purple flowers (\( Pp \))
- Parent 2: White flowers (\( pp \))

#### Punnett Square:
| | \( p \) | \( p \) |
|-----|---------|---------|
| \( P \) | \( Pp \) | \( Pp \) |
| \( p \) | \( pp \) | \( pp \) |

#### Analysis:
- Offspring genotypes: \( Pp \) and \( pp \).
- Phenotypes:
- \( Pp \): Purple (dominant)
- \( pp \): White (recessive)

#### Ratios:
- Genotypic Ratio: \( 50\% \) \( Pp \), \( 50\% \) \( pp \)
- Phenotypic Ratio: \( 50\% \) Purple, \( 50\% \) White

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Problem 3: Curly Hair vs. Straight Hair

#### Key:
- Curly hair is dominant over straight hair.
- Genotypes:
- Curly hair: \( CC \) or \( Cc \)
- Straight hair: \( cc \)

#### Cross:
- Parent 1: Curly hair (\( Cc \))
- Parent 2: Straight hair (\( cc \))

#### Punnett Square:
| | \( c \) | \( c \) |
|-----|---------|---------|
| \( C \) | \( Cc \) | \( Cc \) |
| \( c \) | \( cc \) | \( cc \) |

#### Analysis:
- Offspring genotypes: \( Cc \) and \( cc \).
- Phenotypes:
- \( Cc \): Curly (dominant)
- \( cc \): Straight (recessive)

#### Ratios:
- Genotypic Ratio: \( 50\% \) \( Cc \), \( 50\% \) \( cc \)
- Phenotypic Ratio: \( 50\% \) Curly, \( 50\% \) Straight

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Final Answers:

1. Red Fruit vs. Yellow Fruit:
- Genotypic Ratio: \( 0\% \) \( RR \), \( 100\% \) \( Rr \), \( 0\% \) \( rr \)
- Phenotypic Ratio: \( 100\% \) Red, \( 0\% \) Yellow

2. Purple Flowers vs. White Flowers:
- Genotypic Ratio: \( 50\% \) \( Pp \), \( 50\% \) \( pp \)
- Phenotypic Ratio: \( 50\% \) Purple, \( 50\% \) White

3. Curly Hair vs. Straight Hair:
- Genotypic Ratio: \( 50\% \) \( Cc \), \( 50\% \) \( cc \)
- Phenotypic Ratio: \( 50\% \) Curly, \( 50\% \) Straight

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Boxed Final Answer:

\[
\boxed{
\begin{array}{l}
\text{1. Genotypic Ratio: } 0\% \, RR, \, 100\% \, Rr, \, 0\% \, rr \\
\text{ Phenotypic Ratio: } 100\% \, \text{Red}, \, 0\% \, \text{Yellow} \\
\text{2. Genotypic Ratio: } 50\% \, Pp, \, 50\% \, pp \\
\text{ Phenotypic Ratio: } 50\% \, \text{Purple}, \, 50\% \, \text{White} \\
\text{3. Genotypic Ratio: } 50\% \, Cc, \, 50\% \, cc \\
\text{ Phenotypic Ratio: } 50\% \, \text{Curly}, \, 50\% \, \text{Straight}
\end{array}
}
\]