Chapter 14 - Chromosomes and Human Inheritance · Web viewA woman heterozygous for color blindness (an X-linked recessive allele) marries a man with normal color vision. What is the

Chapter 14 - Chromosomes and Human Inheritance

Multiple Choice

1. How many genes are involved in determining skin color? a. 1 b. 2 c. 10 d. 20 e. more than 100ANSWER: eDIFFICULTY: Bloom's: RememberREFERENCES: 14.1 Shades of SkinLEARNING OBJECTIVES: UDOL.STES.16.14.1 - Examine the rationale behind regional variations in human skin color.

2. Which combination makes the most sense from an evolutionary perspective? a. light skin and vitamin D deficiency b. light skin and extensive exposure to sun c. dark skin and little exposure to sun d. dark skin and folate deficiency e. light skin and little sun, or dark skin and lots of sunANSWER: eDIFFICULTY: Bloom's: UnderstandREFERENCES: 14.1 Shades of SkinLEARNING OBJECTIVES: UDOL.STES.16.14.1 - Examine the rationale behind regional variations in human skin color.

Copyright Cengage Learning. Powered by Cognero. Page 1


Figure 14.3

3. Which of the following is the genetic condition observed in the woman on the left in the above figure? a. Huntington’s disease b. achondroplasia c. triple recessive condition d. galactosemia e. muscular dystrophiesANSWER: bDIFFICULTY: Bloom's: UnderstandREFERENCES: 14.3 Examples of Autosomal Inheritance PatternsPREFACE NAME: Figure 14.3LEARNING OBJECTIVES:

UDOL.STES.16.14.3 - Analyze the inheritance patterns of autosomal dominant disorders and autosomal recessive disorders.

4. Achondroplasia ____. a. is inherited as an autosomal recessive condition b. affects about one in one million people c. affects only homozygotes d. is characterized by abnormally short arms and legsCopyright Cengage Learning. Powered by Cognero. Page 2


e. is inherited as an X-linked disorderANSWER: dDIFFICULTY: Bloom's: RememberREFERENCES: 14.3 Examples of Autosomal Inheritance PatternsLEARNING OBJECTIVES:


5. The probability of producing a normal child by two parents who are carriers for an autosomal recessive disorder is ____. a. 0% b. 25% c. 50% d. 75% e. 100%ANSWER: dDIFFICULTY: Bloom's: ApplyREFERENCES: 14.3 Examples of Autosomal Inheritance PatternsLEARNING OBJECTIVES:


6. What can be said about sex-determination in humans? a. All human sperm carry a Y chromosome. b. 25% of human zygotes are XY. c. All zygotes carry a Y chromosome. d. Sex depends upon which type of sperm fertilizes the egg. e. All human eggs carry a Y chromosome.ANSWER: dDIFFICULTY: Bloom's: Apply

Bloom's: EvaluateREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:

UDOL.STES.16.14.4 - Examine the different types of genetic disorders caused by X-linked inheritance patterns.

7. Which statement about sex chromosomes is correct? a. The Y chromosome carries a greater number of genes for nonsexual traits than does the X. b. X and Y are different in size but carry nearly equal numbers of genes. c. The X chromosome carries more genes for nonsexual traits than does the Y. d. The X chromosome carries only gender-related genes. e. The X chromosome carries the SRY gene.ANSWER: cDIFFICULTY: Bloom's: UnderstandREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


8. Who is a carrier of an X-linked trait?Copyright Cengage Learning. Powered by Cognero. Page 3


a. homozygous dominant female b. heterozygous female c. homozygous recessive female d. homozygous male e. heterozygous maleANSWER: bDIFFICULTY: Bloom's: UnderstandREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


9. A human X-linked disorder is a. found only in males. b. more frequently expressed in females. c. found on the Y chromosome. d. transmitted from father to son. e. more frequently expressed in males.ANSWER: eDIFFICULTY: Bloom's: RememberREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


10. Males tend to be affected in greater numbers by X-linked recessive genetic disorders than are females because a. females have two dominant genes for the disorder. b. males have only one X chromosome. c. males have a double dose of the gene. d. Y chromosomes are not as strong as X chromosomes. e. females have only one X chromosome.ANSWER: bDIFFICULTY: Bloom's: UnderstandREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


11. A woman heterozygous for color blindness (an X-linked recessive allele) marries a man with normal color vision. What is the probability that their first child (male or female) will be color blind? a. 25% b. 50% c. 75% d. 100% e. 0%ANSWER: aDIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsCopyright Cengage Learning. Powered by Cognero. Page 4


LEARNING OBJECTIVES:


12. If a daughter expresses an X-linked recessive trait, she inherited the trait from ____. a. her mother b. her father c. both parents d. neither parent e. her grandmotherANSWER: cDIFFICULTY: Bloom's: Apply

Bloom's: EvaluateREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


13. The potential causes of chromosomal aberrations include a. viruses only. b. radiation only. c. a set of specific chemicals. d. viruses and radiation only. e. viruses, radiation, and various chemicals.ANSWER: eDIFFICULTY: Bloom's: RememberREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.

Excerpt from Figure 14.8

14. The accompanying figure represents which chromosomal change? a. inversion b. deletion c. duplication d. translocation e. aneuploidyANSWER: cCopyright Cengage Learning. Powered by Cognero. Page 5


DIFFICULTY: Bloom's: UnderstandREFERENCES: 14.5 Heritable Changes in Chromosome StructurePREFACE NAME: Figure 14.8LEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.


15. The accompanying figure represents which chromosomal change? a. inversion b. deletion c. duplication d. translocation e. aneuploidyANSWER: aDIFFICULTY: Bloom's: UnderstandREFERENCES: 14.5 Heritable Changes in Chromosome StructurePREFACE NAME: Figure 14.8(1)LEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.


16. The accompanying figure represents which chromosomal change? a. inversion b. deletion c. duplication d. translocation e. aneuploidyANSWER: bCopyright Cengage Learning. Powered by Cognero. Page 6


DIFFICULTY: Bloom's: UnderstandREFERENCES: 14.5 Heritable Changes in Chromosome StructurePREFACE NAME: Figure 14.8(2)LEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.

17. A chromosome's gene sequence that was ABCDEFG before modification and ABCDCDEFG afterward is an example of a. inversion. b. deletion. c. duplication. d. translocation. e. aneuploidy.ANSWER: cDIFFICULTY: Bloom's: ApplyREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.

18. A chromosome's gene sequence that was ABCDEFG before damage and ABFEDCG after is an example of a. inversion. b. deletion. c. duplication. d. translocation. e. aneuploidy.ANSWER: aDIFFICULTY: Bloom's: ApplyREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.

19. A transfer of genes between non-homologous chromosomes is known as a. crossing over. b. aneuploidy. c. trisomy. d. translocation. e. duplication.ANSWER: dDIFFICULTY: Bloom's: RememberREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.

20. Polyploidy can be described as ____. a. only occurring artificially



b. only occurring when there is one set of chromosomes c. fatal to all living things d. occurring in about 20% of flowering plants e. fatal in humans but common in flowering plantsANSWER: eDIFFICULTY: Bloom's: RememberREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:

UDOL.STES.16.14.6 - Examine the ill-effects of a change in human chromosome number using examples.

21. Changes in chromosome number are usually the result of a. genetic displacement. b. trisomy. c. crossing over. d. nondisjunction. e. disjunction.ANSWER: dDIFFICULTY: Bloom's: RememberREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:


22. The failure of chromosomes to separate during mitosis or meiosis is called a. genetic displacement. b. trisomy. c. crossing over. d. nondisjunction. e. disjunction.ANSWER: dDIFFICULTY: Bloom's: RememberREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:


23. Down syndrome involves trisomy ____. a. 3 b. 5 c. 15 d. 19 e. 21ANSWER: eDIFFICULTY: Bloom's: RememberREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:




24. Which syndrome is characterized by a karyotype with 45 chromosomes? a. Turner b. Down c. androgen insensitivity d. Klinefelter e. cri-du-chatANSWER: aDIFFICULTY: Bloom's: RememberREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:


25. What is the sex chromosome composition of a person with Turner syndrome? a. XXX b. XO c. XXY d. XYY e. YYANSWER: bDIFFICULTY: Bloom's: ApplyREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:


26. What is the sex chromosome composition of a person with Klinefelter syndrome? a. XXX b. XO c. XXY d. XYY e. YYANSWER: cDIFFICULTY: Bloom's: ApplyREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:


27. Males that tend to be taller than average and show mild mental impairment may have a. XXY chromosomes. b. XYY chromosomes. c. Turner syndrome. d. Down syndrome. e. Klinefelter syndrome.ANSWER: bDIFFICULTY: Bloom's: Apply



Bloom's: EvaluateREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:


28. PKU detection includes a. prenatal karyotyping. b. urine analysis at puberty. c. blood tests at puberty. d. saliva tests. e. urine analysis and blood tests at birth.ANSWER: eDIFFICULTY: Bloom's: RememberREFERENCES: 14.7 Genetic ScreeningLEARNING OBJECTIVES: UDOL.STES.16.14.7 - Outline the applications of genetic screening and its potential

benefits.

29. Symptoms of phenylketonuria (PKU) may be minimized or suppressed by a diet low in a. serine. b. glycine. c. phenylalanine. d. proline. e. glutamic acid.ANSWER: cDIFFICULTY: Bloom's: RememberREFERENCES: 14.7 Genetic ScreeningLEARNING OBJECTIVES: UDOL.STES.16.14.7 - Outline the applications of genetic screening and its potential

benefits.

30. Amniocentesis involves sampling a. the fetus directly. b. the fetal cells floating in the amniotic fluid. c. sperm. d. blood cells. e. placental cells.ANSWER: bDIFFICULTY: Bloom's: RememberREFERENCES: 14.7 Genetic ScreeningLEARNING OBJECTIVES: UDOL.STES.16.14.7 - Outline the applications of genetic screening and its potential

benefits.

31. Amniocentesis is _____. a. a surgical means of repairing deformities b. a form of chemotherapy that modifies or inhibits gene expression or the function of gene products c. used in prenatal diagnosis to detect chromosomal mutations and metabolic disorders in embryos



d. a form of gene replacement therapy e. commonly performed on newbornsANSWER: cDIFFICULTY: Bloom's: RememberREFERENCES: 14.7 Genetic ScreeningLEARNING OBJECTIVES: UDOL.STES.16.14.7 - Outline the applications of genetic screening and its potential

benefits.

32. A prenatal diagnosis procedure that has recently come into wide use and can be performed earlier than amniocentesis involves sampling the _____. a. yolk sac material b. allantois c. chorion d. yolk sac e. umbilical cordANSWER: cDIFFICULTY: Bloom's: RememberREFERENCES: 14.7 Genetic ScreeningLEARNING OBJECTIVES: UDOL.STES.16.14.7 - Outline the applications of genetic screening and its potential

benefits.

33. It is now possible to analyze the genetics of an in vitro fertilized embryo by a. fetoscopy. b. amniocentesis. c. chorionic villi sampling. d. pre-implantation diagnosis. e. post-implantation diagnosis.ANSWER: dDIFFICULTY: Bloom's: RememberREFERENCES: 14.7 Genetic ScreeningLEARNING OBJECTIVES: UDOL.STES.16.14.7 - Outline the applications of genetic screening and its potential

benefits.

Completion

34. The human has __________ sets of autosomal chromosomes.ANSWER: 22

twenty-twoDIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


35. __________ is a diagnostic tool that reveals missing or extra chromosomes and some structural changes in an individual's chromosomes.ANSWER: Karyotyping



DIFFICULTY: Bloom's: ApplyREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.

36. Rarely, a chromosome's structure becomes altered when part of it undergoes duplication, deletion, __________, or __________.ANSWER: inversion; translocation

translocation; inversionDIFFICULTY: Bloom's: UnderstandREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.

Matching

Choose the most appropriate answer for each.a. 3n; generally sterileb. a chromosome segment is permanently transferred to a nonhomologous chromosomec. (2n - 1); a zygote deprived of a chromosomed. a repeat of a particular DNA sequence in the same chromosome or in nonhomologous onese. (2n + 1); three chromosomes of the same kind are present in a set of chromosomesf. a piece of the chromosome is inadvertently left out during the repair processg. encodes a transport protein in melanosome membranesh. a chromosome segment that has been cut out and rejoined at the same place, but backwardDIFFICULTY: Bloom's: RememberREFERENCES: 14.1 Shades of SkinLEARNING OBJECTIVES: UDOL.STES.16.14.1 - Examine the rationale behind regional variations in human skin color.

37. SLC24A5ANSWER: g

Choose the most appropriate answer for each.a. 3n; generally sterileb. a chromosome segment is permanently transferred to a nonhomologous chromosomec. (2n - 1); a zygote deprived of a chromosomed. a repeat of a particular DNA sequence in the same chromosome or in nonhomologous onese. (2n + 1); three chromosomes of the same kind are present in a set of chromosomesf. a piece of the chromosome is inadvertently left out during the repair processg. encodes a transport protein in melanosome membranesh. a chromosome segment that has been cut out and rejoined at the same place, but backwardDIFFICULTY: Bloom's: RememberREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.



38. duplicationANSWER: d

39. inversionANSWER: h

40. translocationANSWER: b

Choose the most appropriate answer for each.a. 3n; generally sterileb. a chromosome segment is permanently transferred to a nonhomologous chromosomec. (2n - 1); a zygote deprived of a chromosomed. a repeat of a particular DNA sequence in the same chromosome or in nonhomologous onese. (2n + 1); three chromosomes of the same kind are present in a set of chromosomesf. a piece of the chromosome is inadvertently left out during the repair processg. encodes a transport protein in melanosome membranesh. a chromosome segment that has been cut out and rejoined at the same place, but backwardDIFFICULTY: Bloom's: RememberREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:


41. monosomyANSWER: c

42. triploidyANSWER: a

43. trisomyANSWER: e

Match the cause with the disorder.a. autosomal recessive inheritance; lactose metabolism is blockedb. nondisjunction of the twenty-first chromosomal pairc. X-linked recessive inheritanced. nondisjunction of the sex chromosomesDIFFICULTY: Bloom's: RememberREFERENCES: 14.3 Examples of Autosomal Inheritance PatternsLEARNING OBJECTIVES:


44. Down syndromeANSWER: b

45. galactosemiaANSWER: a



46. red-green color blindnessANSWER: c

47. hemophilia AANSWER: c

Match the cause with the disorder.a. autosomal recessive inheritance; lactose metabolism is blockedb. nondisjunction of the twenty-first chromosomal pairc. X-linked recessive inheritanced. nondisjunction of the sex chromosomesDIFFICULTY: Bloom's: RememberREFERENCES: REF: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


48. Turner syndromeANSWER: d

Answer the following questions in reference to the five items listed below.a. 12b. 23c. 24d. 46e. 47DIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


49. How many chromosomes does each somatic cell have in a human male who has two X chromosomes?ANSWER: e

50. Following a gene duplication event involving only five loci, how many chromosomes will a human female have?ANSWER: d

51. How many chromosomes are present in the somatic cells of a child born with Down syndrome (trisomy 21)?ANSWER: e

52. How many chromosomes are present in each cell of the germ cell line for a tetraploid species whose normal complement of chromosomes is 48?ANSWER: c

53. The normal sperm cell of species X carries 11 chromosomes. Following nondisjunction in the formation of secondary spermatocytes and their subsequent fertilization of normal ova, some of the zygotes will have 21 chromosomes, and the remainder will have how many chromosomes?ANSWER: b



Select the best process listed below for each of the following statements. Note that you need to know that the sequence of amino acids directly reflects the sequence of genes that coded for their placement.a. inversionb. deletionc. gene duplicationd. translocatione. additionREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.

54. Homologous sets of genes ABCDEF and aBCdEF are located on nonhomologous chromosomes. Crossing over between them is suppressed because their locations are the result of this.ANSWER: d

Select the best process listed below for each of the following statements. Note that you need to know that the sequence of amino acids directly reflects the sequence of genes that coded for their placement.a. inversionb. deletionc. gene duplicationd. translocatione. insertionDIFFICULTY: Bloom's: ApplyREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES: UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their

outcomes.

55. Homologous sets of genes ABCDEF and AEDCBF are located on homologous chromosomes. ANSWER: a

56. A small region of a protein from three species is sequenced and found to be as follows:species X is alanine, glycine, glycine, threonine, alaninespecies Y is alanine, glycine, threonine, alaninespecies Z is alanine, glycine, glycine, threonine, alanineThe difference in the amino acid sequence of species Y is most likely due to this.ANSWER: b

57. A small region of a protein from three species is sequenced and found to be as follows:species X is alanine, glycine, threonine, alaninespecies Y is alanine, glycine, threonine, alaninespecies Z is alanine, valine, glycine, threonine, alanineThe difference in the amino acid sequence of species Z is most likely due to this.ANSWER: e

58. The nucleotide sequences of homologous regions of DNA of two species are AATGCCCCGTTA and AATGCCCCGCTTA. If this is not the result of a nucleotide base-pair addition, then it is most likely the result of this.ANSWER: b

59. Homologous sets of genes ABCDEF and ABCDEF are located on nonhomologous chromosomes. Copyright Cengage Learning. Powered by Cognero. Page 15


ANSWER: d

Select the disorder that best matches each the following statements.a. galactosemiab. Turner syndromec. progeriad. hemophilia Ae. Down syndromeDIFFICULTY: Bloom's: UnderstandREFERENCES: 14.3 Examples of Autosomal Inheritance PatternsLEARNING OBJECTIVES:


60. This disorder is an autosomal dominant disorder.ANSWER: c

61. This disorder is an autosomal recessive disorder.ANSWER: a

62. This disorder is also known as trisomy 21.ANSWER: e

Select the disorder that best matches each the following statements.a. galactosemiab. Turner syndromec. Klinefelter’s syndromed. hemophilia Ae. Down syndromeDIFFICULTY: Bloom's: UnderstandREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


63. This disorder is an X-linked recessive trait.ANSWER: d

64. This disorder is due to a sex chromosome abnormality probably caused by nondisjunction of sex chromosomes at meiosis.ANSWER: b

Objective Short Answer

65. An X-linked recessive gene (c) produces red-green color blindness. A normal woman whose father was color blind marries a color-blind man.(a) What are the possible genotypes for the mother of the color-blind man?(b) What are the possible genotypes for the father of the color-blind man?(c) What are the chances that the first son will be color blind?(d) What are the chances that the first daughter will be color blind?



ANSWER: (a) Cc or cc(b) CY or cY(c) 1/2(d) 1/2

DIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


66. Color blindness is an X-linked recessive gene. Two normal-vision parents produce a color-blind child.(a) Is this child male or female?(b) What are the genotypes of the parents?(c) What are the chances that their next child will be a color-blind daughter?ANSWER: (a) Male

(b) Cc ' CY(c) no chance to produce a color-blind daughter

DIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


67. Explain why Duchenne muscular dystrophy (DMD), a recessive condition, most commonly occurs in boys.ANSWER: DMD is caused by mutations in the X-linked gene dystrophin. Since males have only one X

chromosome, they will express the recessive traits when only one defective, recessive allele is present.DIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


68. Red-green color blindness is an X-linked recessive trait. Two normal-vision parents have a color-blind son. Indicate the genotype and phenotype of each parent and the son.ANSWER: father CY, mother Cc, son cYDIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


69. Short index fingers (shorter than the ring finger) are dominant in males and recessive in females, whereas long index fingers (as long as or longer than ring fingers) are dominant in females and recessive in males. Give the F2 genotype and phenotype resulting from the cross of a male with long index fingers with a female with short index fingers.ANSWER: F2: 3/4 males with short fingers, 1/4 males with long fingers F2: 3/4 females with long fingers, 1/4

females with short fingersDIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


Subjective Short AnswerCopyright Cengage Learning. Powered by Cognero. Page 17


70. If a father and a son are both color blind and the mother is normal, is it likely that the son inherited color blindness from his father?ANSWER: No, males inherit all X-linked traits from the mother; they inherit only the Y from their fathers.DIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


71. In humans, an X-linked disorder called coloboma iridia (a fissure in the iris) is a recessive trait. A normal couple has an afflicted daughter. The husband sues the wife for divorce on the grounds of infidelity. Would you find in his favor?ANSWER: Yes, the daughter would have to inherit the recessive trait from both parents and since the husband is

normal and has only one X to give, the daughter could not have gotten the recessive allele from him.DIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


72. Hemophilia is caused by an X-linked recessive gene. A normal woman whose father had hemophilia marries a normal man. What are the chances of hemophilia in their children?ANSWER: All females normal but 1/2 of them would be carriers; 1/2 of the males would have hemophilia,

the other 1/2 normal.DIFFICULTY: Bloom's: ApplyREFERENCES: 14.4 Examples of X-Linked Inheritance PatternsLEARNING OBJECTIVES:


73. Some conditions like progeria do not run in families despite being autosomal dominant. How is this possible?ANSWER: If the autosomal dominant trait is either lethal before the individual can successfully reproduce, or has

enough disturbance on phenotype to prohibit reproduction, the afflicted individual will not reproduce and the trait cannot be passed on.

DIFFICULTY: Bloom's: UnderstandREFERENCES: 14.3 Examples of Autosomal Inheritance PatternsLEARNING OBJECTIVES:


74. How did the cessation of crossing-over contribute to the disparity between the X and Y chromosomes?ANSWER: In most chromosomes, crossing-over is a way to make sure that subtle changes are regularly

exchanged and that major differences do not accumulate. In the X and Y chromosomes, the slow accumulation of a region in which crossing-over did not occur prevented genetic exchange between the two and resulted in each evolving differently. It is very similar to taking a population and separating it - each will accumulate its own unique mutations and these will slowly create a significant difference between the two.

DIFFICULTY: Bloom's: UnderstandREFERENCES: 14.5 Heritable Changes in Chromosome StructureLEARNING OBJECTIVES:

UDOL.STES.16.14.5 - Examine the different types of chromosome changes and their outcomes.



75. Which nondisjunction disorder must be due to an event in sperm development: XO, XXX, XXY or XYY?ANSWER: Only XYY would definitely be due to sperm development event. In the other three, the missing or

extra X could be attributed to an error in egg development. However, the extra Y in XYY could only come from the male and must be due to nondisjunction during sperm development.

DIFFICULTY: Bloom's: UnderstandREFERENCES: 14.6 Heritable Changes in Chromosome NumberLEARNING OBJECTIVES:


76. A genetic disorder has been studied through multiple generations using pedigree analysis. Every person expressing the trait has an affected parent, and both sexes are equally affected. This suggests what sort of trait and why?ANSWER: That both males and females are equally impacted suggests the trait is autosomal. That all those

expressing the trait suggest it is dominant. Thus, it is an autosomal dominant trait.DIFFICULTY: Bloom's: UnderstandREFERENCES: 14.3 Examples of Autosomal Inheritance PatternsLEARNING OBJECTIVES:



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Chapter 14 - Chromosomes and Human Inheritance · Web viewA woman heterozygous for color blindness (an X-linked recessive allele) marries a man with normal color vision. What is the