Punnett Squares, Genotypes, and Phenotypes

Front

What are genotypes?

Back

Genotypes are the genetic makeup of an organism, represented by letters (e.g., Aa, BB). They determine the traits that an organism can pass on to its offspring.

Front

What are phenotypes?

Back

Phenotypes are the observable traits or characteristics of an organism, such as color, size, and shape, which result from the interaction of its genotype with the environment.

Front

What shape represents a male in a pedigree chart?

Back

A square represents a male in a pedigree chart.

Front

What shape represents a female in a pedigree chart?

Back

A circle represents a female in a pedigree chart.

Front

What is a homozygous genotype?

Back

A homozygous genotype has two identical alleles for a trait, such as AA or aa.

Front

What is a heterozygous genotype?

Back

A heterozygous genotype has two different alleles for a trait, such as Aa.

Front

What does it mean for a trait to be dominant?

Back

A dominant trait is one that is expressed in the phenotype even when only one allele is present (e.g., P in Pp).

Front

What does it mean for a trait to be recessive?

Back

A recessive trait is only expressed in the phenotype when two copies of the allele are present (e.g., pp).

Front

If a homozygous dominant brown mouse (BB) is crossed with a homozygous recessive tan mouse (bb), what will be the genotype of the offspring?

Back

All offspring will be heterozygous brown (Bb).

Front

In a cross between two heterozygous plants (Pp), what is the expected phenotypic ratio of the offspring?

Back

The expected phenotypic ratio is 3:1 (3 purple flowers to 1 white flower).