Genetics Unit Review

Punnett squares are used to show possible combinations of alleles or to predict the probability of a trait occurring in offspring. A parakeet that is heterozygous for blue feathers (dominant) is crossed with a parakeet that is homozygous for white feathers (recessive). According to the Punnett square for this cross, what percentage of offspring is predicted to have blue feathers?

• 25 percent

• 50 percent

• 75 percent

• 100 percent

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

NGSS.HS-LS3-3

Pea plants can have yellow seeds or green seeds. Which conclusion about the meaning of Y is correct if the allele combination Yy is for yellow seeds?

• yellow and dominant

• green and recessive

• yellow and recessive

• green and dominant

Unattached earlobes is a dominant trait, E. A parent who is homozygous for unattached earlobes is crossed with a parent who is homozygous for attached earlobes. Which describes the genotypes of their offspring?

• 100 percent Ee

• 100 percent unattached earlobes

• 100 percent ee

• 100 percent attached earlobes

Tags

NGSS.HS-LS3-1

In the F₁ generation of a Mendelian cross,

• only the dominant trait is visible.

• only the recessive trait is visible.

• neither the dominant nor recessive trait is visible.

• both the dominant and recessive traits are visible.

If a scientist wanted to follow Mendel’s experiment with a different kind of plant, which type of plant would she examine?

• A plant that cannot self-pollinate.

• A plant that has only recessive alleles.

• A plant that has three alleles for a trait.

• A plant that has only two alleles for a trait.

Glaucoma is a leading cause of blindness. Studies have linked a common form of glaucoma to three genes and more than 20 genetic loci. Which best describes glaucoma?

• a recessive trait that requires multiple recessive alleles to be expressed

• a polygenic trait that is influenced by the alleles of several genes

• a codominant trait that is expressed more often when more dominant alleles are present

• a dominant trait that depends on the presence of only one of many dominant alleles

Mary has type A blood. Her son Bill has type AB blood. Which blood type does Bill's dad have if he is homogenous for blood type?

• A

• B

• AB

• O

Tags

NGSS.HS-LS3-1

If a person has type B blood, which statement describes the antibodies present in his or her blood?

• Only anti-A antibodies are present.

• Only anti-B antibodies are present.

• Both anti-A and anti-B antibodies are present.

• Neither anti-A nor anti-B antibodies are present.

Which Punnett square represents a cross between two parents that are heterozygous for purple flowers?

• 
• 
• 
• 

In daisies, flower color is an incomplete dominant trait. The heterozygous phenotype is purple. Using R for the red allele and B for the blue allele - cross two purple flowers. What percent of the offspring will be red?

• 25%

• 50%

• 0%

• 100%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2