Punnett Square and Genetic Crosses

The video tutorial explains how to use a Punnett square to predict genetic outcomes in guinea pigs, focusing on hair color. It covers setting up a monohybrid cross, understanding dominance, and calculating genotypic ratios. The process involves placing alleles from heterozygous parents on a grid, crossing them, and analyzing the resulting offspring to determine the genotypic ratio of homozygous dominant, heterozygous, and homozygous recessive traits.

What is the first step in working with a Punnett Square?

• Determine the phenotypic ratio

• Extract information from the problem

• Identify the dominant and recessive traits

• Draw the square

What does it mean if a guinea pig is heterozygous?

• It has one dominant and one recessive allele

• It has two dominant alleles

• It has two recessive alleles

• It has no alleles

Where do you place the alleles of the first parent in a Punnett Square?

• In the center of the square

• At the bottom of the square

• On the left side of the square

• At the top of the square

What is the result of crossing a dominant allele with a recessive allele in a Punnett Square?

• Heterozygous

• Homozygous recessive

• Homozygous dominant

• No offspring

What type of cross involves only one trait?

• Monohybrid cross

• Dihybrid cross

• Polyhybrid cross

• Trihybrid cross

What is the genotypic ratio for a monohybrid cross of two heterozygous parents?

• 3:1

• 1:2:1

• 2:2

• 1:1

How many homozygous dominant offspring are expected in the given monohybrid cross?

• Three

• Two

• One

• Zero

How many heterozygous offspring are expected in the given monohybrid cross?

• Zero

• One

• Two

• Three

How many homozygous recessive offspring are expected in the given monohybrid cross?

• Three

• Zero

• One

• Two

What is the purpose of a Punnett Square?

• To identify the dominant trait

• To predict the genotypes of offspring

• To calculate the number of offspring

• To determine the phenotypic ratio