7.3 Monohybrid Punnett Squares 2023

Front

What is a monohybrid cross?

Back

A monohybrid cross is a genetic cross between two individuals that differ in a single trait, where one trait is dominant and the other is recessive.

Front

What does it mean for an allele to be dominant?

Back

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

Front

What does it mean for an allele to be recessive?

Back

A recessive allele is one that only expresses its trait when two copies are present in the genotype.

Front

What is the genotype of a heterozygous individual?

Back

A heterozygous individual has two different alleles for a particular gene, represented as 'Aa'.

Front

What is the genotype of a homozygous dominant individual?

Back

A homozygous dominant individual has two identical dominant alleles for a particular gene, represented as 'AA'.

Front

What is the genotype of a homozygous recessive individual?

Back

A homozygous recessive individual has two identical recessive alleles for a particular gene, represented as 'aa'.

Front

What is a Punnett square?

Back

A Punnett square is a diagram used to predict the genotypes of offspring from a genetic cross.

Front

In a monohybrid cross, what is the expected phenotypic ratio of offspring from a heterozygous x homozygous recessive cross?

Back

The expected phenotypic ratio is 1:1.

Front

If two heterozygous individuals are crossed, what is the expected genotypic ratio of their offspring?

Back

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

Front

What percentage of offspring will have a recessive phenotype when two heterozygous individuals are crossed?

Back

25% of the offspring will have a recessive phenotype.