Exam 11: Mendel and the Gene Idea

The frequency of heterozygosity for the sickle-cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following?

The following questions refer to the pedigree chart in Figure 11.2 for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. Figure 11.2 -What is the probability that individual III-1 is Ww?

Use the following pedigree (Figure 11.3) 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 11.3 -From this pedigree, how does this trait seem to be inherited?

Use the following information to answer the questions below. Feather color in budgies is determined by two different genes, Y and B, one for pigment on the outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. -A blue budgie is crossed with a white budgie. Which of the following results is not possible?

Which of the following is an example of polygenic inheritance?

Use the following information to answer the questions below. Feather color in budgies is determined by two different genes, Y and B, one for pigment on the outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. -Two blue budgies were crossed. Over the years, they produced 22 offspring, 5 of which were white. What are the most likely genotypes for the two blue budgies?

Use Figure 11.1 and the following description to answer the questions below. In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in Figure 11.1, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Figure 11.1 -Which of the boxes marked 1-4 correspond(s) to plants with dark leaves?

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?

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

Which of the following describes the ability of a single gene to have multiple phenotypic effects?

Use the following information to answer the questions below. Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. -If true-breeding red long radishes are crossed with true-breeding white oval radishes, the F1 will be expected to be which of the following?

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 flies that are heterozygous for both the bent wing gene and the vestigial wing gene are mated, what is the probability of offspring with bent wings only?

The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason?

Use the following information to answer the questions below. Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently. -If 1,000 F2 offspring resulted from the cross, approximately how many of them would you expect to have red, terminal flowers?

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

Refer to the following information to answer the questions below. Humanoids on the newly explored planet Brin (in a hypothetical galaxy in ~50 years from the present) have a gene structure similar to our own, but many very different plants and animals. -If the environmental parameters, such as temperature, humidity, atmosphere, sunlight, and so on, are mostly Earthlike, which of the following do you expect of its types of leaves, stems, and flowers?

The following questions refer to the pedigree chart in Figure 11.2 for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. Figure 11.2 -What is the likelihood that the progeny of IV-3 and IV-4 will have the trait?

Mendel accounted for the observation that traits that had disappeared in the F1 generation reappeared in the F2 generation by proposing that

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 Figure 11.1 and the following description to answer the questions below. In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in Figure 11.1, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Figure 11.1 -Which of the boxes correspond(s) to plants with a heterozygous genotype?