Genotypes, Phenotypes and Punnett Squares

What is the phenotype of an organism?

• The genetic makeup of an organism

• The physical expression of the genotype

• The combination of recessive alleles

• The location of a gene on a chromosome

In a monohybrid cross, what genotypic ratio is expected in the offspring when both parents are heterozygous for a trait?

• 1:2:1

• 3:1

• 9:3:3:1

• 1:1

Which of the following represents a homozygous recessive genotype?

• Aa

• AA

• aa

• A

If a trait's allele is dominant, what will the phenotype be if the genotype is heterozygous?

• The recessive trait will be expressed.

• The dominant trait will be expressed.

• The traits will blend together.

• Neither trait will be expressed.

What is the purpose of a Punnett square?

• To determine the actual outcome of a genetic cross

• To predict the possible outcomes of a genetic cross

• To confirm the parental genotypes

• To calculate the phenotypic ratios of the previous generation

In a monohybrid cross between two heterozygous parents (Aa x Aa), what is the expected phenotypic ratio of the offspring?

• 1:2:1

• 3:1

• 9:3:3:1

• 1:1

What does it mean if an allele is recessive?

• It is always expressed in the phenotype.

• It is expressed only when two copies are present.

• It is more common in the population.

• It can mask the expression of other alleles.

Which of the following genotypes is heterozygous?

• BB

• Bb

• bb

• BBB

If a plant with the genotype Tt is crossed with a plant with the genotype tt, what percentage of the offspring will likely have the recessive phenotype?

• 0%

• 25%

• 50%

• 100%

In a Punnett square, what does each box represent?

• A unique genotype of the parents

• A possible genotype of the offspring

• The actual phenotype of the offspring

• The dominant allele in the genotype