Unit 5 Genetics 2024

Front

What is a dominant allele?

Back

A dominant allele is a version of a gene that can mask the effect of a recessive allele. It is expressed in the phenotype even if only one copy is present.

Front

What is a recessive allele?

Back

A recessive allele is a version of a gene that is only expressed in the phenotype when two copies are present (homozygous).

Front

What does genotype mean?

Back

Genotype refers to the genetic makeup of an organism, specifically the alleles it possesses for a particular trait.

Front

What does phenotype mean?

Back

Phenotype refers to the observable characteristics or traits of an organism, which result from the interaction of its genotype with the environment.

Front

What is a Punnett Square?

Back

A Punnett Square is a diagram used to predict the outcome of a genetic cross by showing the possible combinations of alleles from the parents.

Front

What is the purpose of a Punnett Square?

Back

The purpose of a Punnett Square is to visualize and calculate the probability of different genotypes and phenotypes in offspring.

Front

If an organism has the genotype Bb, what are the possible phenotypes?

Back

The possible phenotypes are brown eyes (dominant trait) since B (brown) is dominant over b (blue).

Front

What is the expected phenotype ratio from a Bb x bb cross?

Back

The expected phenotype ratio is 1 brown-eyed (Bb) to 1 blue-eyed (bb), or 50% brown and 50% blue.

Front

What does it mean for a trait to be 'masked'?

Back

When a dominant trait is 'masked', it means that the presence of a dominant allele prevents the expression of a recessive allele.

Front

What is homozygous?

Back

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