Porth's Essentials of Pathophysiology, 4e

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Cell and Tissue Function

U N I T 1

5. Human insulin, prepared by recombinant DNA technology, is now available for the treatment of diabetes mellitus. A. Explain the techniques used for the production of a human hormone using this technology. 6. Cystic fibrosis is a disorder of the cell membrane chloride channel that causes the exocrine glands of the body to produce abnormally thick mucus resulting in the development of chronic obstructive lung disease, pancreatitis, and infertility in men. A. Explain how a single mutant gene can produce such devastating effects. B. The disease is transmitted as a single-gene recessive trait. Describe the inheritance of the disorder using Figure 5-11. 7. Adult polycystic kidney disease is transmitted as an autosomal dominant trait. A. Explain the parent-to-child transmission of this disorder. B. Although the disease is transmitted as an autosomal dominant trait, some people who inherit the gene may develop symptoms early in life, others may develop them later in life, and still others may never develop significant symptoms of the disease. Explain. Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell . 5th ed. New York, NY: Garland Science; 2008:195–499. Bartolomei MS, Ferguson-Smith AC. Mammalian genomic imprinting. Cold Spring Harb Perspect Biol. 2011;3:w002592. Cheng J, Kapranov P, Drenkow J, et al. Transcriptional maps of 10 human chromosomes at 5-nucleotide resolution. Science. 2005;308:1149–1154. Fischer A, Cavazzana-Calvo M. Wither gene therapy? The Scientist. 2006;20(2):36–40. Gibbs R. Deeper into the genome. Nature. 2005;437:1233–1234. Gibson G, Muse SV. A Primer of Genome Science . Sunderland, MA: Sinauer Associates, Inc.; 2004. Jegalian K, Lahn BT. Why the Y is so weird. Sci Am Feb. 2001:56–61. Jorde LB, Carey JC, Bamshad MJ. Medical Genetics . 4rd ed. Phildelphia, PA: Mosby Elsevier; 2010. Klug WS, Cummings MR. Essentials of Genetics . 5th ed. Upper Saddle River, NJ: Pearson Prentice Hall; 2005. Lieberman M, Marks AD. Marks' Basic Medical Biochemistry: A Clinical Approach . 4th ed. Philadelphia, PA: Wolters Kluwer Health | Lippincott Williams & Wilkins; 2012:193–309. McElheny VK. The human genome project. The Scientist. 2006;20(2):42–48. Moore KL, Persaud TVN, Torchia MG. The Developing Human: Clinically Orientated Embryology . 9th ed. Philadelphia, PA: Elsevier Saunders; 2013. Myers S, Bottolo L, Freeman C, et al. A fine-scale map of recombination rates and hotspots across the human genome. Science. 2005;310:321–324. B I B L I O G R A P H Y

SUMMARY CONCEPTS (continued)

R E V I EW E X E R C I S E S 1. The Human Genome Project has revealed that humans have only approximately 21,000 genes. Only about 2% of the genome encodes instructions for protein synthesis, whereas 50% consist of repeat sequences that do not code proteins. A. Use this information to explain how this small number of protein-encoding genes is able to produce the vast array of proteins needed for organ and structural development in the embryo, as well as those needed for normal function of the body in postnatal life. 2. A child about to undergo surgery is typed for possible blood transfusions. His parents are told that he is type O positive. Both his mother and father are type A positive. A. How would you go about explaining this variation in blood type to the parents? 3. The posttranslational folding of proteins is essential to their proper functioning and degradation. A. Hypothesize on how age-related changes in the folding of proteins in the central nervous system could contribute to the development of the neurofibrillary tangles that are characteristic of Alzheimer disease. 4. More than 100,000 people die of adverse drug reactions each year; another 2.2 million experience serious reactions; whereas others fail to respond at all to the therapeutic actions of drugs. A. Explain how the use of information about single-nucleotide polymorphisms might be used to map individual variations in drug responses. and reproduced many times over. As a result, proteins that formerly were available only in small amounts (e.g., human insulin) can now be made in large quantities once their respective genes have been isolated. Deoxyribonucleic acid fingerprinting, which relies on recombinant DNA technologies and those of genetic mapping, is often used in forensic investigations. ■■ A newer strategy for management of genetic disorders focuses on gene silencing by using ribonucleic acid interference (RNAi) technology to stop genes from making unwanted disease proteins.