Punnett Squares 3.11.22

Front

What is a Punnett Square?

Back

A Punnett Square is a diagram used to predict the genetic makeup of offspring from two parents by showing all possible combinations of alleles.

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene (e.g., BB or bb).

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene (e.g., Bb).

Front

What are alleles?

Back

Alleles are different forms of a gene that can exist at a specific locus on a chromosome.

Front

What is the genotype of an organism?

Back

The genotype is the genetic constitution of an organism, represented by the alleles it possesses (e.g., BB, Bb, or bb).

Front

What is the phenotype of an organism?

Back

The phenotype is the observable physical or biochemical characteristics of an organism, determined by its genotype.

Front

If a pea plant has the genotype Pp, what is its phenotype?

Back

The phenotype is purple flowers, as the allele for purple (P) is dominant over the allele for white (p).

Front

What is the expected phenotype ratio from a monohybrid cross of two heterozygous parents (Bb x Bb)?

Back

The expected phenotype ratio is 3:1, with 3 showing the dominant trait and 1 showing the recessive trait.

Front

In a Punnett Square, what does each box represent?

Back

Each box represents a possible genotype of the offspring resulting from the combination of alleles from each parent.

Front

What is the significance of dominant and recessive alleles?

Back

Dominant alleles mask the effect of recessive alleles in the phenotype when present.