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 combinations of alleles from the parents.

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene, such as FF or ff.

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene, such as Ff.

Front

What is a dominant allele?

Back

A dominant allele is an allele that expresses its trait even when only one copy is present in a heterozygous genotype.

Front

What is a recessive allele?

Back

A recessive allele is an allele that only expresses its trait when two copies are present in a homozygous genotype.

Front

How do you determine the probability of a trait using a Punnett Square?

Back

You fill in the Punnett Square with the alleles from each parent and then count the combinations to find the probability of each genotype.

Front

What is the genotype of a purple-horned unicorn if purple is dominant over pink?

Back

The genotype could be either homozygous dominant (PP) or heterozygous (Pp).

Front

In a Punnett Square, where are the parent alleles written?

Back

The parent alleles are written outside of the boxes, typically on the top and left side.

Front

What is the probability of obtaining a homozygous recessive offspring from two heterozygous parents?

Back

The probability is 25%.

Front

What does it mean if an organism is homozygous recessive?

Back

It means the organism has two recessive alleles for a trait, such as ff.