Punnett Squares

Front

What is a Punnett Square?

Back

A Punnett Square is a diagram used to predict the genetic makeup of offspring from two 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 a genotype?

Back

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

Front

What is a phenotype?

Back

A phenotype is the physical appearance or observable traits of an organism, resulting from its genotype.

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene (e.g., AA or aa).

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene (e.g., Aa).

Front

What is the probability of homozygous recessive offspring from a cross of Aa x Aa?

Back

25%.

Front

How do you set up a Punnett Square?

Back

Place one parent's alleles on the top and the other parent's alleles on the side, then fill in the boxes.

Front

What is the probability of obtaining a heterozygous offspring from a cross of Aa x Aa?

Back

50%.

Front

What is the expected phenotype ratio from a cross of Aa x Aa?

Back

3:1 ratio of dominant to recessive phenotypes.