Punnett squares

Front

What is a Punnett square?

Back

A Punnett square is a diagram used to predict the genotype and phenotype combinations of offspring from a genetic cross.

Front

What do the letters in a Punnett square represent?

Back

The letters represent alleles, where uppercase letters denote dominant alleles and lowercase letters denote recessive alleles.

Front

What is the genotype of an organism with two identical alleles?

Back

The genotype is homozygous.

Front

What is the genotype of an organism with two different alleles?

Back

The genotype is heterozygous.

Front

What is the phenotypic ratio of a monohybrid cross between two heterozygous parents (Aa x Aa)?

Back

The phenotypic ratio is 3:1.

Front

What is the expected phenotype ratio for a dihybrid cross (AaBb x AaBb)?

Back

The expected phenotype ratio is 9:3:3:1.

Front

What is incomplete dominance in genetics?

Back

Incomplete dominance is a form of inheritance where the phenotype of the heterozygote is intermediate between the phenotypes of the homozygotes.

Front

What is the probability of obtaining a homozygous recessive offspring (aa) from a cross between two heterozygous parents (Aa x Aa)?

Back

The probability is 25%.

Tags

NGSS.HS-LS3-3

Front

How do you determine the probability of different genotypes in offspring?

Back

You can determine the probability by using a Punnett square to visualize all possible combinations of alleles.

Tags

NGSS.HS-LS3-3

Front

What is the significance of dominant and recessive alleles in inheritance?

Back

Dominant alleles mask the effect of recessive alleles in heterozygous individuals.