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, DD, yy).

Front

What is a phenotype?

Back

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

Front

In a heterozygous genotype, which allele is expressed in the phenotype?

Back

The dominant allele is expressed in the phenotype.

Front

What does homozygous mean?

Back

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

Front

What does heterozygous mean?

Back

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

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

If red petals are dominant, what is the genotype of a homozygous dominant flower?

Back

The genotype of a homozygous dominant flower would be RR.

Front

What is the probability of obtaining a homozygous genotype from a Punnett square?

Back

The probability can vary; for example, it can be 25%, 50%, or 100% depending on the parents' genotypes.

Front

What is the difference between dominant and recessive alleles?

Back

Dominant alleles are expressed in the phenotype even when only one copy is present, while recessive alleles are only expressed when two copies are present.

Front

What does it mean if an organism is described as 'purebred'?

Back

A purebred organism has a homozygous genotype, meaning it has two identical alleles for a trait.