Unit 7: BIO.3B.1&2 Practice Test

A cross between two pea plants was performed in which both pea plants were tall. In this plant species, tallness (T) is dominant over shortness (t). From this cross, 1,000 pea plants were produced, and the heights of the offspring plants were recorded.

Assuming that both of the parent plants were heterozygous, what answer correctly reflects the numbers of offspring pea plants (out of 1,000) of each height that would be predicted from this cross?

• W

• X

• Y

• Z

Tags

NGSS.HS-LS3-2

An organism has the genotype of Bb for a certain trait. Which of the following describes the genotype of this organism?

• Homozygous

• Heterozygous

• Inbred

• Codominant

A gene can have alternate forms that give different traits, such as blue eyes and brown eyes. What are these alternate forms called?

• Gametes

• Centromeres

• Homologous

• Alleles

A homozygous dominant individual will have what type of offspring?

• Offspring that will always exhibit the dominant trait.

• Offspring that will exhibit the dominant trait only if the other parent is also dominant.

• Offspring that will always exhibit the recessive trait.

• Offspring that will exhibit the recessive trait if the other parent has a recessive allele.

Tags

NGSS.HS-LS3-1

When is a recessive allele for a trait expressed in the phenotype of an individual?

• When it is paired with a dominant allele.

• When it is paired with another recessive allele

• When it occurs in a heterozygous individual

• When it occurs in a homozygous dominant individual

Brown eye color (B) is dominant over blue eye color (b). What percentage of heterozygous individuals for eye color will have brown eyes?

• 0%

• 25%

• 50%

• 100%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Which of the following is the best method to determine a dog’s phenotype?

• By looking at the dog

• By looking at the dog’s parents

• By mating the dog and examining its offspring

• By examining the dog’s karyotype

Brown eye color (B) is dominant over blue eye color (b). Debbie has blue eyes, and Pete has brown eyes. Together, they have 5 children. Four of their children have brown eyes and one has blue eyes. What are the genotypes of Debbie and Pete for eye color?

• Debbie is bb, and Pete is BB

• Debbie is bb, and Pete is Bb

• Debbie is Bb, and Pete is bb

• Debbie and Pete are both Bb

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Cystic fibrosis is an autosomal recessive disorder. What is the disease risk for children to be born with cystic fibrosis if both parents are carriers? (Hint: A “carrier” has one allele for the disease).

• 25%

• 50%

• 75%

• 100%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

In pea plants, purple flower color (W) is dominant over white flower color (w). If two pea plants with purple flowers are crossed to produce offspring with white flowers, what must be the genotypes of the two parent plants?

• WW and ww

• WW and Ww

• Ww and Ww

• WW and WW

Tags

NGSS.HS-LS3-1