Genetics Review

Front

What is a recessive trait?

Back

A recessive trait is a characteristic that is only expressed when two alleles for that trait are present. For example, in pea plants, the trait for short stems is recessive.

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a specific gene, such as Aa.

Front

What is the result of crossing a homozygous dominant brown mouse (BB) with a heterozygous brown mouse (Bb)?

Back

The result is 100% brown offspring.

Front

What is the phenotype of a heterozygous organism?

Back

The phenotype of a heterozygous organism can be dominant or a mix of traits, depending on the dominance of the alleles.

Front

What allele represents large wings in genetics?

Back

The allele 'D' represents large wings, while 'd' represents small wings.

Front

What is a homozygous trait?

Back

A homozygous trait is a characteristic that is expressed when two identical alleles are present, such as AA or aa.

Front

What is a Punnett square used for?

Back

A Punnett square is a diagram used to predict the genetic outcomes of a cross between two organisms.

Front

What does it mean if an organism is purebred?

Back

A purebred organism has identical alleles for a trait, such as AA or aa.

Front

What is the difference between genotype and phenotype?

Back

Genotype refers to the genetic makeup of an organism (e.g., AA, Aa, aa), while phenotype refers to the observable traits (e.g., brown or tan color).

Front

What is the principle of dominance?

Back

The principle of dominance states that some alleles are dominant and will mask the presence of recessive alleles in the phenotype.