Punnett squares

Front

What is a Punnett square?

Back

A Punnett square is a diagram used to predict the outcome of a genetic cross by showing the possible allele combinations from the parents.

Front

What do the letters in a Punnett square represent?

Back

The letters represent alleles, where uppercase letters denote dominant alleles and lowercase letters denote recessive alleles.

Front

What is the genotype of an organism?

Back

The genotype is the genetic makeup of an organism, represented by the combination of alleles (e.g., AA, Aa, aa).

Front

What is the phenotype of an organism?

Back

The phenotype is the observable physical or biochemical characteristics of an organism, determined by its genotype.

Front

What is the difference between homozygous and heterozygous genotypes?

Back

Homozygous genotypes have two identical alleles (e.g., AA or aa), while heterozygous genotypes have two different alleles (e.g., Aa).

Front

How do you determine the phenotype ratio from a Punnett square?

Back

The phenotype ratio is determined by counting the number of offspring with each phenotype and expressing it as a ratio.

Front

What is the expected phenotype ratio for a monohybrid cross between two heterozygous parents (Aa x Aa)?

Back

The expected phenotype ratio is 3:1, with 3 showing the dominant phenotype and 1 showing the recessive phenotype.

Front

What is the expected genotype ratio for a monohybrid cross between two heterozygous parents (Aa x Aa)?

Back

The expected genotype ratio is 1:2:1, representing the genotypes AA, Aa, and aa.

Front

What does it mean if an organism is homozygous recessive?

Back

An organism is homozygous recessive if it has two copies of the recessive allele (e.g., aa), resulting in the expression of the recessive phenotype.

Front

In a dihybrid cross, what is the expected phenotype ratio?

Back

The expected phenotype ratio for a dihybrid cross (e.g., AaBb x AaBb) is 9:3:3:1.