Exam 14: Mendel and the Gene Idea

Flower position, stem length, and seed shape were three characters that Mendel studied. Each is controlled by an independently assorting gene and has dominant and recessive expression as follows: Character Dominant Recessive Flower position Axial (A) Terminal (a) Stem length Tall (T) Dwarf (t) Seed shape Round (R) Wrinkled (r) If a plant that is heterozygous for all three characters is allowed to self-fertilize, what proportion of the offspring would you expect to be as follows? (Note: Use the rules of probability instead of a huge Punnett square.) A)Homozygous for the three dominant traits B)Homozygous for the three recessive traits C)Heterozygous for all three characters D)Homozygous for axial and tall, heterozygous for seed shape

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 likelihood that the progeny of IV-3 and IV-4 will have wooly hair?

Cystic fibrosis (CF)is a Mendelian disorder in the human population that is inherited as a recessive. Two normal parents have two children with CF. The probability of their next child being normal for this characteristic is which of the following?

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?

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 14.1 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 14.1, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. -Which of the boxes marked 1-4 correspond to plants with dark leaves?

The relationship between genes S and N is an example of

What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?

Mendel was able to draw his ideas of segregation and independent assortment because of the influence of which of the following?

It was important that Mendel examined not just the F₁ generation in his breeding experiments, but the F₂ generation as well, because

What is the probability that each of the following pairs of parents will produce the indicated offspring? (Assume independent assortment of all gene pairs.) A)AABBCC × aabbcc AaBbCc B)AABbCc × AaBbCc AAbbCC C)AaBbCc × AaBbCc AaBbCc D)aaBbCC × AABbcc AaBbCc

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?

Two pea plants heterozygous for the characters of pod color and pod shape are crossed. Draw a Punnett square to determine the phenotypic ratios of the offspring.

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?

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?

Which of the following terms best describes when the phenotype of the heterozygote differs from the phenotypes of both homozygotes?

A cross between homozygous purple-flowered and homozygous white-flowered pea plants results in offspring with purple flowers. This demonstrates

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. A dwarf, red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F₁ individuals?

A man with type A blood marries a woman with type B blood. Their child has type O blood. What are the genotypes of these individuals? What other genotypes, and in what frequencies, would you expect in offspring from this marriage?

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?