Exam 14: Mendel and the Gene Idea

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?

Use the following information to answer the questions below. Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. -In one type cross of black × black, the results were as follows: 9/16 black 4/16 yellow 3/16 brown The genotype aabb must result in which of the following?

Which of the following calculations require that you utilize the addition rule?

How could you best predict the maximum number of alleles for a single gene whose polypeptide product is known?

Use the following information to answer the questions below. Drosophila (fruit flies) usually have long wings (+) but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg). -If a homozygous bent wing fly is mated with a homozygous vestigial wing fly, which of the following offspring would you expect?

Use the following information to answer the questions below. Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower color is dominant to white (r). The heterozygous condition results in pink (Rr) flower color. -If snapdragons are heterozygous for height as well as for flower color, a mating between them will result in what ratio?

Use the following information to answer the questions below. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. -Which of the following is a possible phenotype for the father?

Use the following information to answer the questions below. Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. -How many genes must be responsible for these coat colors in Labrador retrievers?

Use the following information to answer the questions below. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. -Which of the following is a possible genotype for the mother?

The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following?

Marfan syndrome in humans is caused by an abnormality of the connective tissue protein fibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the spine, sometimes weakened arterial walls, and sometimes ocular problems, such as lens dislocation. Which of the following would you conclude about Marfan syndrome from this information?

Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. What does this suggest?

Why did the F₁ offspring of Mendel's classic pea cross always look like one of the two parental varieties?

Most genes have many more than two alleles. However, which of the following is also true?

Use the following pedigree (Figure 14.3) for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis. Figure 14.3 -The affected woman in generation IV is thinking about her future and asks her oncologist (cancer specialist)whether she can know whether any or all of her children will have a high risk of the same cancer. The doctor would be expected to advise which of the following? I.genetic counseling II.prenatal diagnosis when/if she becomes pregnant III.testing to see whether she has the allele IV.testing to see whether her future spouse or partner has the allele

Use the following information to answer the questions below. Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. -These results indicate which of the following?

Why did Mendel continue some of his experiments to the F₂ or F₃ generation?

Black fur in mice (B)is dominant to brown fur (b). Short tails (T)are dominant to long tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?

Use the following information to answer the questions below. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. -Which of the following is a possible partial genotype for the son?

Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?