Genetics Review

Front

What is a phenotype?

Back

The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences.

Front

What is a genotype?

Back

The genetic constitution of an individual, specifically the alleles present for a particular gene.

Front

What does homozygous mean?

Back

Having two identical alleles for a particular gene (e.g., YY or yy).

Front

What does heterozygous mean?

Back

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

Front

What is the principle of dominance?

Back

In a heterozygous genotype, one allele may mask the expression of another allele.

Front

What is incomplete dominance?

Back

A genetic situation in which one allele does not completely dominate another allele, resulting in a phenotype that is a blend of the two.

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What is codominance?

Back

A genetic scenario where both alleles in a heterozygote are fully expressed, resulting in offspring with a phenotype that is neither dominant nor recessive.

Front

How many alleles does an offspring receive from each parent?

Back

One allele from each parent, totaling two alleles for each trait.

Front

What is a Punnett Square?

Back

A diagram used to predict the outcome of a particular cross or breeding experiment, showing the possible genotypes of offspring.

Front

What is a dominant trait?

Back

A trait that is expressed in the phenotype even when only one copy of the allele is present.