Genetics

Front

What is a Punnett Square?

Back

A Punnett Square is a diagram used to predict the genotypes of a particular cross or breeding experiment. It shows the possible combinations of alleles from the parents.

Front

What does it mean for a trait to be dominant?

Back

A dominant trait is one that will appear in the phenotype even if only one allele is present. It masks the effect of a recessive allele.

Front

What is a genotype?

Back

A genotype is the genetic makeup of an organism, specifically the alleles it possesses for a particular trait.

Front

What is a phenotype?

Back

A phenotype is the observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

Front

What is the genotypic ratio from a cross of two heterozygous plants (Tt x Tt)?

Back

1:2:1 (1 TT : 2 Tt : 1 tt)

Front

What is the phenotypic ratio from a cross of two heterozygous plants (Tt x Tt)?

Back

3:1 (3 tall : 1 short)

Front

How many alleles does an offspring receive from each parent?

Back

One allele from each parent, for a total of two alleles for each trait.

Front

What is a homozygous genotype?

Back

A homozygous genotype has two identical alleles for a particular trait, either dominant (AA) or recessive (aa).

Front

What is a heterozygous genotype?

Back

A heterozygous genotype has two different alleles for a particular trait (e.g., Aa).

Front

What is a recessive trait?

Back

A recessive trait is one that is masked by a dominant trait and only expressed in the phenotype when two recessive alleles are present (bb).