Ch. 14 Genetics Flashcards
Which of the following provides an example of epistasis?
In rabbits and many other mammals, one genotype (cc) prevents any fur color from developing.
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?
All of the genes controlling the traits behaved as if they were on different chromosomes.
Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this?
pleiotropy
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.
Among the F2 offspring, what is the probability of plants with white axial flowers?
3/16
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?
8
Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize a particular amino acid. The amino acid is not otherwise produced by humans. Therefore, the most efficient and effective treatment is which of the following?
Regulate the diet of the affected persons to severely limit the uptake of the amino acid.
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?
3/6
Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. What does this suggest?
that the parents were both heterozygous for a single trait
What do we mean when we use the terms monohybrid cross and dihybrid cross?
A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid cross involves only one.
In each generation of this family after generation I, the age at diagnosis is significantly lower than would be found in nonfamilial (sporadic) cases of this cancer (~ 63 years). What is the most likely reason?
Hereditary (or familial) cases of this cancer typically occur at earlier ages than do nonfamilial forms.
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?
environmental factors such as soil pH
Mendel’s observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?
Anaphase 1 of meiosis
The following questions refer to the pedigree chart in Figure 14.2 for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle.
What is the probability that individual III-1 is Ww?
1
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?
190
Given the parents AABBCc × AabbCc, assume simple dominance for each trait and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?
3/4
