Exam 14: Mendel and the Gene Idea

The following questions refer to the pedigree chart in Figure 14.2 for a family, some of whose members exhibit the dominant trait, wooly hair. Affected individuals are indicated by an open square or circle. Figure 14.2 -What is the genotype of individual II-5?

Pea plants were particularly well suited for use in Mendel's breeding experiments for all of the following reasons except that

Which describes the ABO blood group system?

Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?

Which of the following is an example of polygenic inheritance?

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?

When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?

In a cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?

Phenylketonuria (PKU)is an inherited disease caused by a recessive allele. If a woman and her husband, who are both carriers, have three children, what is the probability of each of the following? A)All three children are of normal phenotype. B)One or more of the three children have the disease. C)All three children have the disease. D)At least one child is phenotypically normal. (Note: Remember that the probabilities of all possible outcomes always add up to 1.)

In mice, black color (B)is dominant to white (b). At a different locus, a dominant allele (A)produces a band of yellow just below the tip of each hair in mice with black fur. This gives a frosted appearance known as agouti. Expression of the recessive allele (a)results in a solid coat color. If mice that are heterozygous at both loci are crossed, what is the expected phenotypic ratio of their offspring?

Hutchinson-Gilford progeria is an exceedingly rare human genetic disorder in which there is very early senility, and death, usually of coronary artery disease, at an average age of approximately 13. Patients, who look very old even as children, do not live to reproduce. Which of the following represents the most likely assumption?

What is the difference between a monohybrid cross and a dihybrid cross?

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?

Two characters that appear in a 9:3:3:1 ratio in the F₂ generation should have which of the following properties?

In some plants, a True-breeding, red-flowered strain gives all pink flowers when crossed with a white-flowered strain: CᴿCᴿ (red)× CᵂCᵂ (white)→ CᴿCᵂ (pink). If flower position (axial or terminal)is inherited as it is in peas (see Table 14.1 in your textbook), what will be the ratios of genotypes and phenotypes of the F₁ generation resulting from the following cross: axial-red (True-breeding)× terminal-white? What will be the ratios in the F₂ generation?

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

In 1981, a stray black cat with unusual rounded, curled-back ears was adopted by a family in California. Hundreds of descendants of the cat have since been born, and cat fanciers hope to develop the curl cat into a show breed. Suppose you owned the first curl cat and wanted to develop a True-breeding variety. How would you determine whether the curl allele is dominant or recessive? How would you obtain True-breeding curl cats? How could you be sure they are True-breeding?

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 characteristic. -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?

A scientist discovers a DNA-based test for the allele of a particular gene. This and only this allele, if homozygous, produces an effect that results in death at or about the time of birth. Of the following, which is the best use of this discovery?

Imagine that you are a genetic counselor, and a couple planning to start a family comes to you for information. Charles was married once before, and he and his first wife had a child with cystic fibrosis. The brother of his current wife, Elaine, died of cystic fibrosis. What is the probability that Charles and Elaine will have a baby with cystic fibrosis? (Neither Charles nor Elaine has cystic fibrosis.)