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, showing the possible combinations of alleles.

Front

What does genotype mean?

Back

Genotype refers to the genetic constitution of an individual, represented by letters (e.g., AA, Aa, aa).

Front

What does phenotype mean?

Back

Phenotype is the observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

Front

What is the probability of getting a homozygous dominant offspring (AA) from a cross of AA x Aa?

Back

50%.

Front

If B = brown fur and b = white fur, what is the genotype of an offspring with white fur?

Back

bb.

Front

What is the expected phenotype ratio from a monohybrid cross (e.g., Aa x Aa)?

Back

3:1 ratio of dominant to recessive phenotype.

Front

What is the probability of getting a heterozygous offspring (Bb) from a cross of Bb x Bb?

Back

50%.

Front

In a Punnett square, what do the letters on the top and side represent?

Back

The letters represent the alleles contributed by each parent.

Front

What is the expected genotype ratio from a dihybrid cross (e.g., AaBb x AaBb)?

Back

1:2:1:2:4:2:1:2:1.

Front

What is the significance of a recessive allele?

Back

A recessive allele is only expressed in the phenotype if two copies are present (homozygous).