Punnett Squares Practice

Front

What is a Punnett Square?

Back

A Punnett Square is a diagram used to predict the genetic makeup of offspring from two parents based on their genotypes.

Front

What does it mean for a trait to be dominant?

Back

A dominant trait is one that will express itself in the phenotype even if only one copy of the allele is present.

Front

What does it mean for a trait to be recessive?

Back

A recessive trait is one that will only express itself in the phenotype if two copies of the allele are present.

Front

What is the genotype of a homozygous organism?

Back

A homozygous organism has two identical alleles for a particular gene, such as AA or aa.

Front

What is the genotype of a heterozygous organism?

Back

A heterozygous organism has two different alleles for a particular gene, such as Aa.

Front

If a tall plant (Tt) is crossed with another tall plant (TT), what is the probability of having a tall offspring?

Back

100%.

Front

In a Punnett Square, what do the letters represent?

Back

The letters represent the alleles contributed by each parent.

Front

What is the phenotypic ratio of a monohybrid cross between two heterozygous parents (Aa x Aa)?

Back

The phenotypic ratio is 3:1 (3 dominant: 1 recessive).

Front

What is the genotypic ratio of a monohybrid cross between two heterozygous parents (Aa x Aa)?

Back

The genotypic ratio is 1:2:1 (1 homozygous dominant: 2 heterozygous: 1 homozygous recessive).

Front

What does it mean for an organism to be homozygous dominant?

Back

An organism is homozygous dominant if it has two dominant alleles for a trait, such as TT.