Human Diseases, 8th Edition - Chapter 5

Chapter 5: Heredity and Disease CHAPTER OVERVIEW The anatomy and physiology of cells and cellular components are discussed. The role of genes and inheritance is introduced. Transmission of hereditary diseases is reviewed. Abnormal chromosome diseases are listed and explained. Genetic counseling and diagnosis of hereditary diseases are reviewed. TRANSITION GUIDE/NEW TO THE EIGHTH EDITION Chapter reviewed to ensure accuracy and to include any updates or changes in chapter content. New art was incorporated into the chapter to enhance student learning. Expanded the Diseases at a Glance section at the end of the chapter. Updated and reviewed the professional references at the end of the chapter. CHAPTER OUTLINE DNA and Chromosomes DNA Is the Cell's Master Code Chromosomes Genes and Inheritance The Human Genome and Disease Transmission of Hereditary Diseases Autosomal Dominant Disorders Autosomal Recessive Disorders Sex-Linked Inheritance Familial Diseases Abnormal Chromosome Diseases Down Syndrome Sex Anomalies Turner's Syndrome Klinefelter's Syndrome Hermaphroditism Genetic Counseling and Diagnosis Diagnosis of Genetic Diseases Gene Therapy for Genetic Diseases Congenital Disorders CHAPTER OBJECTIVES Describe DNA's composition and its role in heredity Explain the transmission of hereditary diseases Understand how disease is reflected in abnormal karyotype and chromosome structure Compare and contrast congenital diseases and genetic disorders Understand how gene therapy might be used to treat genetic diseases and disorders INSTRUCTIONAL GOALS Objective 1: Describe DNA's composition and its role in heredity. Utilize the PowerPoint presentations as a starting point for your lecture. Objective 2: Explain the transmission of hereditary diseases. Utilize the PowerPoint presentations as a starting point for your lecture. Objective 3: Understand how disease is reflected in abnormal karyotype and chromosome structure. Utilize the PowerPoint presentations as a starting point for your lecture. Objective 4: Compare and contrast congenital diseases and genetic disorders. Utilize the PowerPoint presentations as a starting point for your lecture. Review the feature Prevention PLUS!: Huntington's Disease. Objective 5: Understand how gene therapy might be used to treat genetic diseases and disorders. Utilize the PowerPoint presentations as a starting point for your lecture. WORKSHEET 1: Define the Terms alleles amniocentesis autosomes chorionic villus sampling chromosomes congenital disorders deoxyribonucleic acid (DNA) diploid dominant Down syndrome genes haploid hermaphrodites heterozygous homozygous karyotype Klinefelter's syndrome multifactorial pseudohermaphrodites recessive sex chromosomes sex-linked inheritance trisomy 21 WORKSHEET 2: Testbank Questions and Answers 5.1 Multiple-Choice Questions 1) _____ are made from sequences of A, T, G, and C, arranged in different orders and in different lengths. A) Autosomes B) Chromosomes C) Genes D) Haploids Answer: C Objective 1 2) Inside the nucleus, DNA is packaged with proteins into _____. A) autosomes B) chromosomes C) genes D) haploids Answer: B Objective 1 3) The complete chromosomal composition of the nucleus is called the _____. A) allele B) diploid C) haploid D) karyotype Answer: D Objective 1 4) Only gametes contain 23 chromosomes, one chromosome of each pair, a condition called _____. A) allele B) diploid C) haploid D) recessive Answer: C Objective 1 5) Somatic cells contain 46 chromosomes in 23 pairs, a condition called _____. A) allele B) diploid C) haploid D) recessive Answer: B Objective 1 6) If alleles are different, then a person is _____ for the trait that allele expresses. A) diploid B) haploid C) heterozygous D) homozygous Answer: C Objective 1 7) Some alleles always produce their trait when inherited and are said to be _____. A) dominant B) heterozygous C) homozygous D) recessive Answer: A Objective 1 8) Huntington's disease is an _____ disorder. A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: A Objective 2 9) Polydactyly is an _____ disorder. A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: A Objective 2 10) Achondroplasia is an _____ disorder A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: A Objective 2 11) Marfan syndrome is an _____ disorder. A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: A Objective 2 12) Familial hypercholesterolemia is an _____ disorder. A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: A Objective 2 13) Cystic fibrosis is an _____ disorder. A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: B Objective 2 14) Hemochromatosis is an _____ disorder A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: B Objective 2 15) Phenylketonuria is an _____ disorder A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: B Objective 2 16) _____ is an inborn error of sugar metabolism that can lead to impaired mental development and liver damage. A) Albinism B) Galactosemia C) Sickle cell anemia D) Tay-Sachs Answer: A Objective 2 17) _____ is a disorder in which abnormal hemoglobin causes deformed red blood cells. A) Albinism B) Galactosemia C) Sickle cell anemia D) Tay-Sachs Answer: B Objective 2 18) _____ is a rare disease, occurring mostly among families of eastern European Jewish origin, which causes neurological damage and death in infants. A) Albinism B) Galactosemia C) Sickle cell anemia D) Tay-Sachs Answer: D Objective 2 19) _____ is an absence of the pigment melanin, resulting in colorless white skin, hair, and eyes. A) Albinism B) Galactosemia C) Sickle cell anemia D) Tay-Sachs Answer: C Objective 2 20) Galactosemia is an _____ disorder A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: B Objective 2 21) Sickle cell anemia is an _____ disorder. A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: B Objective 2 22) Tay-Sachs is an _____ disorder. A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: B Objective 2 23) Albinism is an _____ disorder. A) autosomal dominant B) autosomal recessive C) X-linked dominant D) X-linked recessive Answer: B Objective 2 24) The Y chromosome is _____. A) large and carries several genes B) large but carries few genes C) small and carries few genes D) small but carries several genes Answer: C Objective 2 25) Turner's syndrome results from the presence of _____. A) only one X chromosome B) only one Y chromosome C) two X chromosomes D) two Y chromosomes Answer: A Objective 3 26) A person with Klinefelter's syndrome, there is _____. A) an extra X chromosome B) an extra Y chromosome C) no X chromosomes D) no Y chromosomes Answer: A Objective 3 27) Cerebal palsy is a _____. A) congenital disorder B) heterozygous disorder C) homozygous disorder D) sex-linked disorder Answer: A Objective 4 28) Hydrocephalus is a _____. A) congenital disorder B) heterozygous disorder C) homozygous disorder D) sex-linked disorder Answer: A Objective 4 29) Spina bifida is a _____. A) congenital disorder B) heterozygous disorder C) homozygous disorder D) sex-linked disorder Answer: A Objective 4 30) Cleft lip and cleft palate are a _____. A) congenital disorder B) heterozygous disorder C) homozygous disorder D) sex-linked disorder Answer: A Objective 4 5.2 True/False Questions 1) The four chemical bases that make up DNA are adenine, thymine, guanine, and cystosine. Answer: True Objective 1 2) Normally, each person has forty-four (twenty-two pairs) of chromosomes. Answer: False Objective 1 3) A female has a combination of one X and one Y chromosome. Answer: False Objective 1 4) If two of the same allele is inherited the person is homozygous for that trait. Answer: True Objective 1 5) Hereditary diseases or disorders often result from a defective gene or genes that produce a defective protein or no protein at all. Answer: True Objective 2 6) Huntington's disease is a neurodegenerative disorder. Answer: True Objective 2 7) Achondroplasia results in achondroplastic dwarfism. Answer: True Objective 2 8) Cystic fibrosis affects the glands that secrete mucus, leading to recurrent, severe respiratory infections and gastrointestinal disorders. Answer: True Objective 2 9) Phenylketonuria (PKU) is an inborn error of metabolism that leads to buildup of toxic products in the brain. Answer: True Objective 2 10) The loss of an autosomal chromosome is usually incompatible with life. Answer: True Objective 3 11) A Down syndrome child is always mentally impaired to some degree. Answer: True Objective 3 12) Pseudohermaphrodites have either testes or ovaries, but the remainder of the anatomy is mixed. Answer: True Objective 4 13) An amniocentesis can only detect about 50 of the thousands of known genetic disorders. Answer: False Objective 5 14) Congenital defects usually occur during the first two months of pregnancy. Answer: True Objective 4 15) Congenital diseases can be transmitted to offspring. Answer: False Objective 4 5.3 Short Answer Questions 1) DNA, which stands for _____ acid, is the chemical blueprint that directs all cell activities. Answer: deoxyribonucleic Objective 1 2) Forty-four of the chromosomes are called _____. Answer: autosomes Objective 1 3) Two of the chromosomes, the X and Y chromosomes, are called _____ chromosomes. Answer: sex Objective 1 4) Specialized cells in the ovaries and testis, divide by a process called _____, during which each of the 23 pairs of chromosomes are separated. Answer: meiosis Objective 1 5) _____ are alternative forms of a gene, located on each of the paired chromosomes. Answer: Alleles Objective 1 6) The complete set of DNA in a living thing is known as its _____. Answer: genome Objective 1 7) Abnormalities of sex-linked inheritance tend to occur more frequently in _____. Answer: males Objective 2 8) Polydactyly is a condition of extra _____. Answer: fingers Objective 2 9) _____ syndrome is a condition of defective connective tissue, leading to weak blood vessels, joints, and vision problems. Answer: Marfan Objective 2 10) Hemochromatosis is an _____ storage disorder. Answer: iron Objective 2 11) The cause of familial diseases there does not seem to be a single gene, but the effect of several genes working together, called a _____ trait. Answer: multifactorial Objective 2 12) In Down syndrome chromosome 21 is inherited in triplicate, a condition called _____ 21. Answer: trisomy Objective 3 13) Diagnosis of a genetic disorder may involve an _____, where a small amount of amniotic fluid is withdrawn after the fourteenth week of pregnancy. Answer: amniocentesis Objective 3 14) _____ villus sampling involves removing cells from the villi through the cervix. Answer: Chorionic Objective 5 15) _____ disorders are those present at birth or shortly after, not including those caused by genetic or chromosomal abnormalities. Answer: Congenital Objective 4 WORKSHEET 3: Discussion Questions and Answers 5.4 Discussion Questions 1. Describe what an allele is, and use that word to define the difference between homozygous and heterozygous. Answer: Alleles are alternative forms of a gene, and one of these alleles is located on each of the paired chromosomes. If two of the same allele is inherited the person is homozygous for that trait. If the alleles are different then the person is heterozygous for that trait. 2. Describe the difference between a dominant trait and a recessive trait. Answer: Some alleles always produce their trait when inherited and are said to be dominant. The result of inheriting the dominant allele is usually the same whether a person is homozygous or heterozygous. Other alleles are recessive, and only manifest themselves when the person is homozygous for the trait. 3. Describe the differences between autosomal dominant disorders and autosomal recessive disorders. Answer: In autosomal recessive disorders, expression of the disease occurs only when that particular allele is inherited from each parent, making the person homozygous for that trait. In autosomal dominant disorders, the defective allele is usually transmitted by a parent who is heterozygous for the trait. The disease will appear in every generation of the family. 4. Briefly describe what sex-linked inheritance is. Answer: The defective allele is located on the X chromosome. The Y chromosome is small and carries few genes. Thus, when a male inherits a defective recessive gene found on the X chromosome, that trait is expressed. 5. Provide the name of one of the four common sex-linked inheritance disorders, and identify how it affects the body. Answer: Duchenne's muscular dystrophy - abnormal muscle development and wasting. Color blindness - the inability to see color. Hemophilia - several forms of blood clotting disorders Fragile X syndrome - developmental disorder with mental impairment 6. Describe the characteristic appearance of a Down syndrome child. Answer: The eyes appear slanted because of an extra fold of skin at the upper, medial corner of the eye. The tongue is course and often protrudes, while the nose is short and flat. The child has a short stature, and the sex organs are underdeveloped. A straight crease extends across the palm of the hand, and the little finger is often shorter than normal. 7. Compare and contrast Turner's Syndrome with Klinefelter's syndrome. Answer: Turner's syndrome: results from the presence of only one X chromosome. The person appears to be female, but the ovaries do not develop; there is no ovulation or menstruation, and the person is sterile. The mammary nipples are widely spaced, the breasts do not develop, and the person is short of stature and has a stocky build. Klinefelter's syndrome: results from the presence of an extra X chromosome. The person appears to be male but has small testes that fail to mature and produce no sperm. At puberty, female secondary sex characteristics emerge, the breast enlarge, and female distribution of hair develops. Little facial hair develops, and the general appearance is that of an immature young adult. The person is tall and slender with abnormally long legs.