Genetics Review

Front

What is a dihybrid cross?

Back

A genetic cross that involves two traits being studied simultaneously.

Front

What is co-dominance in genetics?

Back

A form of inheritance where both alleles in a heterozygote are fully expressed, resulting in a phenotype that is neither dominant nor recessive.

Front

What does an extra chromosome 21 indicate?

Back

It indicates Down syndrome, a genetic disorder caused by the presence of an extra copy of chromosome 21.

Front

In a Punnett square, what does box 3 represent in a dihybrid cross?

Back

It represents one of the possible genotype combinations of the offspring.

Front

In a heterozygous genotype, which allele is expressed in the phenotype?

Back

The dominant allele.

Front

What is the purpose of a Punnett square?

Back

To predict the genotypes and phenotypes of offspring from a genetic cross.

Front

Define genotype.

Back

The genetic constitution of an individual, represented by the alleles they possess.

Front

Define phenotype.

Back

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

Front

What is the difference between dominant and recessive alleles?

Back

Dominant alleles express their trait even in the presence of a recessive allele, while recessive alleles only express their trait when two copies are present.

Front

What is incomplete dominance?

Back

A form of inheritance where the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes.