Punnett Square Practice

Front

What is a Punnett Square?

Back

A Punnett Square is a diagram used to predict the genetic makeup of offspring from a cross between two parents.

Front

What does homozygous mean?

Back

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

Front

What does heterozygous mean?

Back

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

Front

What is the genotype of a homozygous recessive organism?

Back

The genotype of a homozygous recessive organism is represented as 'aa'.

Front

What is the phenotype of a homozygous dominant organism?

Back

The phenotype of a homozygous dominant organism is the dominant trait, such as tallness in pea plants (T).

Front

If a homozygous tall plant (TT) is crossed with a homozygous short plant (tt), what are the expected offspring genotypes?

Back

All offspring will be heterozygous tall (Tt).

Front

What is the expected genotype ratio from a cross between two heterozygous plants (Tt x Tt)?

Back

The expected genotype ratio is 1 TT : 2 Tt : 1 tt.

Front

What is the probability of obtaining a homozygous recessive offspring from a cross between two heterozygous parents (Aa x Aa)?

Back

The probability is 25% or 1 in 4.

Front

What does it mean if a trait is dominant?

Back

A dominant trait is one that is expressed in the phenotype even if only one dominant allele is present.

Front

What is the expected phenotype ratio from a cross between two heterozygous plants (Tt x Tt)?

Back

The expected phenotype ratio is 3 tall : 1 short.