Mendel and Punnett Squares

Front

What is a dominant trait?

Back

A dominant trait is a genetic trait that is expressed in the phenotype even when only one copy of the allele is present. For example, in pea plants, round shape (R) is a dominant trait.

Front

What is a recessive trait?

Back

A recessive trait is a genetic trait that is only expressed in the phenotype when two copies of the allele are present. For example, in pea plants, wrinkled shape (r) is a recessive 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 a genotype?

Back

A genotype is the genetic constitution of an individual, represented by the alleles inherited from the parents.

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene, such as 'RR' or 'rr'.

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene, such as 'Rr'.

Front

What is the purpose of 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 an allele?

Back

An allele is a variant form of a gene that can produce different traits. For example, the gene for pea shape has two alleles: R (round) and r (wrinkled).

Front

What is the expected phenotypic ratio from a cross of Rr x Rr?

Back

The expected phenotypic ratio from a cross of Rr x Rr is 3:1, with 75% round peas and 25% wrinkled peas.

Front

What is the expected genotypic ratio from a cross of Rr x Rr?

Back

The expected genotypic ratio from a cross of Rr x Rr is 1:2:1, with 1 RR, 2 Rr, and 1 rr.