Question

1. complete the punnett square problems using \b\ for black and \b\ for white. give genotypes and phenotypes.

• a heterozygous individual is crossed with a homozygous recessive plant.

• a homozygous dominant plant is crossed with a hybrid.

Explanation:

First Problem: Heterozygous (Bb) × Homozygous Recessive (bb)

Step1: Determine Parent Genotypes

Heterozygous: \( Bb \) (produces gametes \( B \) and \( b \)). Homozygous recessive: \( bb \) (produces gametes \( b \) and \( b \)).

Step2: Create Punnett Square

	\( B \)	\( b \)
\( b \)	\( Bb \)	\( bb \)

Step3: Calculate Genotype Ratios

• \( Bb \): 2/4 = 50%
• \( bb \): 2/4 = 50%

Step4: Determine Phenotypes

• \( Bb \): Black (dominant allele \( B \) present)
• \( bb \): White (recessive alleles only)
• Phenotype Ratios: Black (50%), White (50%)

Second Problem: Homozygous Dominant (BB) × Hybrid (Bb)

Step1: Determine Parent Genotypes

Homozygous dominant: \( BB \) (produces gametes \( B \) and \( B \)). Hybrid: \( Bb \) (produces gametes \( B \) and \( b \)).

Step2: Create Punnett Square

	\( B \)	\( B \)
\( b \)	\( Bb \)	\( Bb \)

Step3: Calculate Genotype Ratios

• \( BB \): 2/4 = 50%
• \( Bb \): 2/4 = 50%

Step4: Determine Phenotypes

• \( BB \) and \( Bb \): Both have dominant \( B \), so Black.
• Phenotype Ratio: Black (100%)

Answer:

(First Problem Genotype/Phenotype):

• Genotypes: \( Bb \) (50%), \( bb \) (50%)
• Phenotypes: Black (50%), White (50%)