Genotype, Phenotype, & Punnett Squares

Front

What is a genotype?

Back

A genotype is the genetic makeup of an organism, represented by the alleles it possesses (e.g., AA, Aa, aa).

Front

What is a phenotype?

Back

A phenotype is the physical appearance or observable traits of an organism, determined by its genotype and environmental factors.

Front

What does dominant trait mean?

Back

A dominant trait is a characteristic that is expressed in the phenotype even when only one allele is present (e.g., yellow seeds in pea plants).

Front

What does recessive trait mean?

Back

A recessive trait is a characteristic that is only expressed in the phenotype when two copies of the allele are present (e.g., green seeds in pea plants).

Front

What is a Punnett square?

Back

A Punnett square is a diagram used to predict the genetic outcomes of a cross between two organisms, showing the possible genotypes of offspring.

Front

What does homozygous mean?

Back

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

Front

What does heterozygous mean?

Back

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

Front

If G = green and g = yellow, what is the phenotype of a plant with genotype Gg?

Back

The phenotype of a plant with genotype Gg is green, because green is the dominant trait.

Front

What is the purpose of a Punnett square?

Back

The purpose of a Punnett square is to visualize and calculate the probability of different genotypes and phenotypes in offspring.

Front

What is the expected phenotype ratio in a monohybrid cross of two heterozygous parents (e.g., Aa x Aa)?

Back

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