Dominant/Recessive

Front

What is a dominant gene?

Back

A dominant gene is a gene that expresses its trait even when only one copy is present in the genotype.

Front

What is a recessive gene?

Back

A recessive gene is a gene that only expresses its trait when two copies are present in the genotype.

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene, such as Gg.

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene, such as AA or rr.

Front

What is a phenotype?

Back

Phenotype is the observable physical or biochemical characteristics of an organism, determined by its genotype.

Front

What is a genotype?

Back

Genotype is the genetic constitution of an individual, represented by the alleles it possesses.

Front

If a guinea pig has the genotype Hh, what is its phenotype?

Back

The phenotype is black hair, since black hair (H) is dominant.

Front

What is the phenotype of an organism with the genotype tt?

Back

The phenotype is not able to roll the tongue, since not being able to roll the tongue (t) is recessive.

Front

What is the difference between dominant and recessive traits?

Back

Dominant traits are expressed with one allele, while recessive traits require two alleles to be expressed.

Front

If a person is homozygous recessive for a trait, what does that mean?

Back

It means they have two recessive alleles for that trait, such as rr.