Genetic Word Problems

In cocker spaniels, the allele for a black coat color (B) is dominant over the allele for brown coat color (b). If a brown cocker spaniel (bb) is crossed with a heterozygous black cocker spaniel (Bb), which of the following genotypic rations can be expected?

• 0 BB: 2 Bb: 2bb

• 1BB: 2Bb: 1bb

• 2BB: 0Bb: 2bb

• 2BB: 1 Bb: 0 bb

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Tomato plants usually have hairy stems. Hairless stems are present in tomato plants that are homozygous recessive for this trait. If the stem characteristics are determined by a single gene, what is the expected outcome of crossing two tomato plants that are heterozygous (Hh x Hh) for hairy stems?

• 75% hairy; 25% hairless

• 100% hairy

• 100% hairless

• 50% hairy; 50% hairless

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Normal centipedes have yellow bodies, and this body color is dominant. A mutation in the gene for body color can produce centipedes with an orange body color. A homozygous yellow centipede is crossed with a homozygous orange centipede. What is the predicted outcome of this genetic cross?

• All will be orange

• Of the offspring, 75% will have yellow bodies, and 25% will have orange bodies.

• All will be yellow

• Of the offspring, 75% will have orange bodies, and 25% will have yellow bodies.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

NGSS.HS-LS3-3

In polar bears, the allele for a black coat color (R) is dominant over the allele for brown coat color (r). If a brown polar bear is crossed with a heterozygous black polar bear, which of the following genotypic rations can be expected?

• 0 RR: 2 Rr: 2 rr

• 1 RR: 2 Rr: 1 rr

• 2 RR: 0 Rr: 2 rr

• 2 RR: 1 Rr: 0 rr

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

NGSS.HS-LS3-3

In a certain species of cheetah, gray fur (G) is dominant over cream-colored fur (g). If a homozygous gray cheetah is crossed with a cream-colored cheetah, the phenotypes of the offspring would be--

• all gray

• all cream

• 75% gray

• 50% cream

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

In humans, being a tongue roller (R) is dominant over non-roller (r). A man who is a non-roller marries a woman who is heterozygous for tongue rolling. What percent of their kids will be non-rollers?

• 100%

• 50%

• 25%

• 0%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Brown eyes in humans are dominant to blue eyes. A heterozygous brown-eyed man marries a heterozygous brown-eyed woman. What percent of their kids will have blue eyes?

• 100% blue

• 50% blue

• 25% blue

• 0% blue

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

NGSS.HS-LS3-3

Brown eyes in humans are dominant to green eyes. A heterozygous brown-eyed man marries a green-eyed woman. What percent of their kids will have green eyes?

• 100%

• 50%

• 25%

• 0%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Sonar hearing is a dominant trait in wing bats. Normal hearing is recessive. Cross two heterozygous wing bats. What percent of the offspring will have sonar hearing?

• 100%

• 75%

• 25%

• 0%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

NGSS.HS-LS3-3

White flowers are dominant and yellow flowers are recessive. What percent of the offspring will be yellow if you cross a homozygous white flower with a yellow flower?

• 100%

• 75%

• 50%

• 0%

Tags

NGSS.HS-LS3-1