Genotype, Phenotype, & Punnett Squares

Front

What is a genotype?

Back

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

Front

What is a phenotype?

Back

The physical appearance or observable traits of an organism, determined by its genotype.

Front

What does homozygous mean?

Back

Having two identical alleles for a particular gene (e.g., AA or aa).

Front

What does heterozygous mean?

Back

Having two different alleles for a particular gene (e.g., Aa).

Front

What is a dominant allele?

Back

An allele that expresses its trait even when only one copy is present in the genotype.

Front

What is a recessive allele?

Back

An allele that only expresses its trait when two copies are present in the genotype.

Front

What is a Punnett square?

Back

A diagram used to predict the outcome of a genetic cross by showing the possible combinations of alleles.

Front

In a Punnett square, what do the letters represent?

Back

The letters represent the alleles contributed by each parent.

Front

If a plant has the genotype Rr, what is its phenotype if R is dominant?

Back

The phenotype will show the dominant trait associated with allele R.

Front

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

Back

The expected phenotype ratio is 3:1 (3 dominant: 1 recessive).