Chapter 13 Practice

Which recombination frequency corresponds to perfect linkage and violates the law of independent assortment? a. 0 b. 0.25 c. 0.50 d. 0.75

0

Which recombination frequency corresponds to independent assortment and the absence of linkage? a. 0 b. 0.25 c. 0.50 d. 0.75

0.50

Which of the following codes describes position 12 on the long arm of chromosome 13? a. 13p12 b. 13q12 c. 12p13 d. 12q13

13q12

The genotype XXY corresponds to a. Klinefelter syndrome b. Turner syndrome c. Triplo-X d. Jacob syndrome

Klinefelter syndrome

Which of the following statements about nondisjunction is true? a. Nondisjunction only results in gametes with n+1 or n-1 chromosomes. b. Nondisjunction occurring during meiosis II results in 50 percent normal gametes. c. Nondisjunction during meiosis I results in 50 percent normal gametes. d. Nondisjunction always results in four different kinds of gametes.

Nondisjunction occurring during meiosis II results in 50 percent normal gametes.

Which of the following statements is true? a. Recombination of the body color and red/cinnabar eye alleles will occur more frequently than recombination of the alleles for wing length and aristae length. b. Recombination of the body color and aristae length alleles will occur more frequently than recombination of red/brown eye alleles and the aristae length alleles. c. Recombination of the gray/black body color and long/short aristae alleles will not occur. d. Recombination of the red/brown eye and long/short aristae alleles will occur more frequently than recombination of the alleles for wing length and body color.

Recombination of the red/brown eye and long/short aristae alleles will occur more frequently than recombination of the alleles for wing length and body color.

Abnormalities in the number of X chromosomes tends to have milder phenotypic effects than the same abnormalities in autosomes because of ________. a. deletions b. nonhomologous recombination c. synapsis d. X inactivation

X inactivation

By definition, a pericentric inversion includes the ________. a. centromere b. chiasma c. telomere d. synapse

centromere

The first suggestion that chromosomes may physically exchange segments came from the microscopic identification of ________. a. synapsis b. sister chromatids c. chiasmata d. alleles

chiasmata

In agriculture, polyploid crops (like coffee, strawberries, or bananas) tend to produce ________. a. more uniformity b. more variety c. larger yields d. smaller yields

larger yields

Assume a pericentric inversion occurred in one of two homologs prior to meiosis. The other homolog remains normal. During meiosis, what structure—if any—would these homologs assume in order to pair accurately along their lengths? a. V formation b. cruciform c. loop d. pairing would not be possible

loop

X-linked recessive traits in humans (or in Drosophila) are observed ________. a. in more males than females b. in more females than males c. in males and females equally d. in different distributions depending on the trait

more males than females