Test Prep for AP® Courses

11.

The following figure represents a Drosophila linkage map for genes A-E. The numbers between the gene loci are the relative map units between each gene.

The figure shows vertical lines labelled A through E placed at different points on a horizontal line. The amount of space between each letter is relative to a number value between the two letters. From left to right on the Line, the number 8 is between A and B. The number 12 is between B and C, the number 3 is between C and D and the number 5 is between D and E.
Figure 13.16

Based on the linkage map, which two genes are most likely to segregate together?

  1. A and B
  2. B and C
  3. C and D
  4. D and E
12.

A test cross was made between true-breeding EEWW flies and eeww flies. The resulting F1 generation was then crossed with eeww flies. One hundred offspring in the F2 generation were examined, and it was discovered that the E and W genes were not linked. Which is the correct genotype of the F2 offspring if the genes were linked and if the genes were not linked?

  1. linked: 50 percent EEWW and 50 percent eeww; not linked: 25 percent EeWw, 25 percent , Eeww 25 percent eeWw, and 25 percent eeww
  2. linked: 25 percent Eeww, 50 percent eeWw; not linked: parental genotypes EeWw and eeww
  3. linked: genotypes EeWw and eeww, and recombinant genotypes Eeww and eeWw in the F2 generation are nearly the same irrespective of their linkage
  4. linked: mostly with parental genotypes, Eeww and eeWw; unlinked: 25 percent EeWw and eeww with 75 percent Eeww and eeWw
13.

A cross was made with true-breeding AABB flies and true-breeding aabb flies. The resulting F1 generation then was crossed with true-breeding aabb flies. Based on the linkage map, which F2 generation genotype ratio is most likely to be observed?

This table is titled Number Observed. It has six rows and five columns. The first row is a header row and it labels the table Number Observed from columns two to five. The second row is also a header row and it labels each column. At the top of the first column is a blank space. Underneath this blank space is the first column header F 2 Genotype. The second column header is A. The third column header is B. The fourth column header is C. The fifth column header is D. Under the first column header, F 2 Geno
Figure 13.17

A cross was made with true-breeding AABB flies and true-breeding aabb flies. The resulting F1 generation was then crossed with true-breeding aabb flies. Based on the linkage map, which of the following F2 generation genotype ratios is most likely to be observed?

  1. number observed: AaBb (46), Aabb (4), aaBb (4), Aabb (46)
  2. number observed: AaBb (4), Aabb (46), aaBb (46), Aabb (4)
  3. number observed: AaBb (25), Aabb (25), aaBb (25), Aabb (25)
  4. number observed: AaBb (50), Aabb (0), aaBb (0), Aabb (50)
14.

Which symptom is most likely associated with the disorder shown in the karyotype?

This image is a karyotype showing the 22 pairs of human autosomes and a pair of sex chromosomes. The autosomal chromosome pairs consist of two stick-like structures of approximately the same length and shape. Each pair is labeled 1 through 22. Chromosome pairs 1 and 2 are the longest. Chromosome pairs 21 and 22 are the shortest. The sex chromosomes are labeled as X and Y. The two X chromosomes are significantly longer than the Y chromosomes.

  1. lethality
  2. infertility
  3. heart and bleeding defects
  4. short stature and stunted growth
15.

Which option describes the disorder shown in the karyotype and the social, ethical, or medical issue related to the disorder?

This image is a karyotype showing the 22 pairs of human autosomes and a pair of sex chromosomes. The autosomal chromosome pairs consist of two stick-like structures of approximately the same length and shape. Each pair is labeled 1 through 22. Chromosome pairs 1 and 2 are the longest. Chromosome pairs 21 and 22 are the shortest. The sex chromosomes are labeled as X and Y. The two X chromosomes are significantly longer than the Y chromosomes.
Figure 13.18
  1. Down syndrome (47 XY +21) causes intellectual disability, vision problems, congenital heart disease, and susceptibility to cancer. Healthcare providers often do not discuss the positive aspects of raising a child with Down syndrome and often provide out-of-date information.
  2. Klinefelter syndrome (47 XXY) causes intellectual disability, vision problems, congenital heart disease, and susceptibility to cancer. Arguments are often made against abortion of an affected fetus.
  3. Klinefelter syndrome (47 XXY) causes sterility and reduced testosterone production. Arguments are often made against informing insurance companies about a diagnosis of this disease.
  4. Down syndrome (47 XY +21) causes sterility and lower testosterone production. Arguments are often made against informing insurance companies about a diagnosis of this disease.
16.

Which gene order is the most likely outcome of an inversion mutation in the chromosome shown?

The figure shows vertical lines labeled R through V placed at different points on a horizontal line. The amount of space between each letter is relative to a number value between the two letters. From left to right on the line, the number 6 is between R and S. The number 11 is between S and T, the number 2 is between T and U, and the number 4 is between U and V.

  1. RSTUV
  2. RRSTUV
  3. RSUV
  4. RTSUV
17.

With the help of the diagram given, which statement most appropriately describes nondisjunction and its genetic consequences?

This illustration shows nondisjunction that occurs during meiosis I. Nondisjunction during meiosis I occurs when a homologous pair fails to separate, and results in two gametes with n + 1 chromosomes, and two gametes with n − 1 chromosomes. Nondisjunction during meiosis II would occur when sister chromatids fail to separate, and results in one gamete with n + 1 chromosomes, one gamete with n − 1 chromosomes, and two normal gametes.
Figure 13.19
  1. Nondisjunction occurs when a homologous pair is unable to separate during meiosis I, resulting in the formation of gametes containing n+1 and n-1 chromosomes. This is called aneuploidy.
  2. Nondisjunction occurs due to the inability of sister chromatids to separate during meiosis II, resulting in the formation of gametes containing n+1 and n-1 chromosomes. This results in heart and bleeding defects.
  3. Nondisjunction is the failure of homologous chromosomes to separate during meiosis I or failure of sister chromatids to separate during meiosis II. This results in aneuploid gametes.
  4. Nondisjunction occurs when a pair of homologous chromosomes fails to segregate during meiosis II resulting in the formation of gametes containing n+1, n-1, or n numbers of chromosomes. This results in abnormal growth patterns.
18.

Klinefelter syndrome is —

  1. more severe than Down syndrome, due to gene deletions in this syndrome
  2. more severe than Down syndrome, due to trisomy in Klinefelter syndrome
  3. less severe than Down syndrome, due to monosomy in Down syndrome
  4. less severe than Down syndrome, due to X-inactivation in this disorder