Test Prep for AP® Courses
Don’t like Brussels sprouts? Blame your genes. The chemical PTC (phenylthiocarbamide), which is nearly identical to a compound found in the cabbage family, tastes very bitter for some people. Others cannot detect a taste. The ability to taste PTC is incompletely dominant and is controlled by a gene on chromosome 7.A woman who finds Brussel sprouts mildly distasteful—in other words, who can taste PTC weakly—has a child with a man who hates Brussel sprouts—in other words, who can taste PTC strongly. What is the probability that their son likes Brussel sprouts—in other words, cannot taste PTC?
A couple has three daughters. What is the probability that the next child they have will be a daughter?
- 0 percent
- 25 percent
- 50 percent
- 100 percent
- complete dominance
- incomplete dominance
Petunias can be blue, red, or violet. When a blue flower is crossed with a red flower, all the resulting flowers are violet. Two violet petunias are crossed. Which is the most probable result of the cross?
- 75 percent of the flowers are blue and 25 percent of the flowers are red
- 50 percent of the flowers are blue and 50 percent of the flowers are red
- 75 percent of the flowers are red and 25 percent are blue
- 25 percent of the flowers are blue, 50 percent of the flowers are violet, and 25 percent of the flowers are red
- Gray body and cinnabar eyes are dominant.
- Eye color is sex-linked.
- Body color is sex-linked.
- Gray body and red eyes are dominant.
Female flies from the F1 generation were crossed with true-breeding male flies with black bodies and cinnabareyes. The table below represents the predicted outcome and the data obtained from the cross.
What was the assumption that lead to the predicted numbers?
- The traits assort independently.
- The traits are located on the X chromosome.
- The traits are on the same chromosome.
- The female flies were homozygous for wild type alleles.
Cats can be black, yellow, or calico (black and yellow patches). Coat color is carried on the X chromosome. What type of inheritance is color coat in cats?
- Incomplete dominance
- Codominance, sex linked
- Incomplete dominance, sex linked
Cats can be black, yellow or calico—black and yellow patches. Coat color is carried on the X chromosome. A yellow cat is crossed with a black cat. Assume that the offspring are both male and female. What are the phenotypes of the offspring and in what proportions?
- All the cats are yellow.
- All the cats are black.
- All the cats are calico.
- There is not enough information to answer the question.