Genotype, Phenotype, & Punnett Squares

Front

What is a genotype?

Back

The genotype is the genetic makeup of an organism, represented by the combination of alleles (e.g., GG, Gg, gg).

Front

What is a phenotype?

Back

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

Front

What does homozygous mean?

Back

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

Front

What does heterozygous mean?

Back

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

Front

What is a dominant trait?

Back

A dominant trait is a characteristic that is expressed in the phenotype even when only one copy of the allele is present (e.g., G for green).

Front

What is a recessive trait?

Back

A recessive trait is a characteristic that is expressed in the phenotype only when two copies of the allele are present (e.g., gg for yellow).

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.

Front

How do you determine the genotype of a yellow plant if G = green and g = yellow?

Back

The genotype of a yellow plant is gg.

Front

If a plant has the genotype Aa, what can you say about its alleles?

Back

The plant is heterozygous, having one dominant allele (A) and one recessive allele (a).

Front

What is the purpose of using a Punnett square?

Back

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