Question

1. use the punnett square to predict the results of a pp × pp f1 generation cross.

father’s genes
mother’s genes
genotype ratio:
phenotype ratio:

1. what individuals are bred during a test cross?

a. describe the ratios produced by each test cross.

Explanation:

Question 10

Step1: Determine gametes

Each parent (Pp) can produce two types of gametes: P and p. So father's gametes: P, p; mother's gametes: P, p.

Step2: Fill Punnett square

	P	p
p	Pp	pp

Step3: Calculate genotype ratio

Count genotypes: PP: 1, Pp: 2, pp: 1. So genotype ratio: \( PP : Pp : pp = 1:2:1 \)

Step4: Determine phenotype (assuming P is dominant)

PP and Pp show dominant phenotype, pp shows recessive. So dominant (PP + Pp): 3, recessive (pp): 1. Phenotype ratio: \( \text{dominant} : \text{recessive} = 3:1 \)

A test cross involves breeding an individual with an unknown genotype (usually showing dominant phenotype) with a homozygous recessive individual. This helps determine if the unknown is homozygous dominant or heterozygous.
a. If unknown is homozygous dominant (e.g., PP) × homozygous recessive (pp): all offspring (Pp) show dominant phenotype (ratio \( 1:0 \) dominant:recessive). If unknown is heterozygous (Pp) × homozygous recessive (pp): offspring have \( Pp : pp = 1:1 \), so phenotype ratio \( 1:1 \) dominant:recessive.

Answer:

Genotype ratio: \( PP : Pp : pp = 1:2:1 \)
Phenotype ratio: \( \text{Dominant} : \text{Recessive} = 3:1 \)

Question 11