Punnet Squares

Front

What is a Punnett Square?

Back

A Punnett Square is a diagram used to predict the genotypes and phenotypes of offspring from a genetic cross.

Front

What does it mean for a trait to be dominant?

Back

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

Front

What is the phenotype ratio of offspring from a cross between two heterozygous plants (Pp x Pp) for flower color where purple (P) is dominant?

Back

75% purple flowers, 25% white flowers.

Front

What is the probability of a child having type A blood if one parent has type O blood and the other is heterozygous for type A blood?

Back

50%.

Front

What is the phenotypic ratio of offspring from a heterozygous black mouse (Bb) crossed with a white mouse (bb)?

Back

2 Black: 2 White.

Front

What is phenylketonuria (PKU) and how is it inherited?

Back

PKU is a recessive genetic disorder. A child will inherit PKU only if both parents pass on the recessive allele.

Front

If a man with PKU marries a woman without any alleles for PKU, what is the probability their child will inherit PKU?

Back

0%.

Front

What is the inheritance pattern of red-green colorblindness?

Back

Red-green colorblindness is an X-linked recessive trait.

Front

If a colorblind man has a son with a carrier woman, what is the probability that their next son will also be colorblind?

Back

50%.

Front

What is a genotype?

Back

A genotype is the genetic makeup of an organism, represented by the alleles it possesses.