Biochemistry and Genetics PreTestTMSelf-Assessment and Review Notice Medicine is an ever-changing science. As new research and clinical experience broaden our knowledge, changes in treatment and drug therapy are required. The authors and the publisher of this work have checked with sources believed to be reliable in their efforts to provide information that is complete and generally in accord with the standards accepted at the time of publication. However, in view of the possibility of human error or changes in medical sciences, neither the authors nor the publisher nor any other party who has been involved in the preparation or publication of this work warrants that the information contained herein is in every respect accurate or complete, and they disclaim all responsibility for any errors or omissions or for the results obtained from use of the information contained in this work. Readers are encouraged to confirm the information contained herein with other sources. For example, and in particular, readers are advised to check the prod- uct information sheet included in the package of each drug they plan to administer to be certain that the information contained in this work is accurate and that changes have not been made in the recommended dose or in the contraindications for administration. This recommendation is of particular importance in connection with new or infrequently used drugs. Biochemistry and Genetics PreTestTMSelf-Assessment and Review Third Edition Golder N. Wilson MD, PhD Clinical Professor, Texas Tech University KinderGenome Pediatric Genetics, Dallas, Texas New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto Copyright © 2007 by The McGraw-Hill Companies, Inc. All rights reserved. Manufactured in the United States of America. 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Moonthungal St. George’s University Class of 2006 David Scoville University of Kansas School of Medicine Class of 2008 This page intentionally left blank For more information about this title, click here Contents Preface. ix Introduction . x Note Concerning Disease Examples . xi Abbreviations . xii High-Yield Facts High-Yield Facts in Biochemistry and Genetics . 1 STORAGE AND EXPRESSION OF GENETIC INFORMATION DNA Structure, Replication, and Repair Questions . 59 Answers . 75 Gene Expression and Regulation Questions . 93 Answers . 119 ACID-BASE EQUILIBRIA,AMINO ACIDS, AND PROTEIN STRUCTURE/FUNCTION Acid-Base Equilibria,Amino Acids, and Protein Structure Questions . 147 Answers . 163 Protein Structure/Function Questions . 183 Answers . 196 vii viii Contents INTERMEDIARY METABOLISM Carbohydrate Metabolism Questions . 209 Answers . 223 Bioenergetics and Energy Metabolism Questions . 239 Answers . 251 Lipid,Amino Acid, and Nucleotide Metabolism Questions . 263 Answers . 284 NUTRITION Vitamins and Minerals Questions . 309 Answers . 320 Hormones and Integrated Metabolism Questions . 337 Answers . 351 INHERITANCE MECHANISMS AND BIOCHEMICAL GENETICS Inheritance Mechanisms/Risk Calculations Questions . 373 Answers . 395 Genetic and Biochemical Diagnosis Questions . 419 Answers . 442 Bibliography . 469 Appendix . 471 Index . 485 Preface The new edition of Biochemistry and Genetics PreTest: Self-Assessment and Review is based in part on earlier editions prepared by Golder N. Wilson, MD, PhD, Department of Pediatrics, Texas Tech University Health Sciences Center, Cheryl Ingram-Smith, PhD, and Kerry S. Smith, PhD, Department of Genetics, Biochemistry, and Life Science Studies Clemson University Clemson, South Carolina, and by Francis J. Chlapowski, PhD, Department of Biochemistry and Molecular Biology, University of Massachusetts Medical School. All questions are in single-best-answer format and a large number are analogous to those of the United States Medical Licensing Examination (USMLE), Step 1. Questions are updated to the most current editions of leading textbooks in medical biochemistry and medical genetics. ix Copyright © 2007 by The McGraw-Hill Companies, Inc. Click here for terms of use. Introduction Each PreTest Self-Assessment and Review allows medical students to com- prehensively and conveniently assess and review their knowledge of a par- ticular basic science, in this instance biochemistry and genetics. The 500 questions parallel the format and degree of difficulty of the questions found in the United States Medical Licensing Examination (USMLE) Step 1. The Appendix lists subjects from the USMLE guidelines and shows the relevant question numbers from this PreTest book that relate to these subjects. Each question is accompanied by an answer, a paragraph explanation, and a specific page reference to an appropriate textbook. A bibliography listing sources can be found at the end of this text, and a list of abbrevia- tions used in the text follows this introduction. Over 200 clinical disorders or processes are discussed and related to biochemical and/or genetic mech- anisms (see the appendix for a list of disease examples). For genetic disor- ders, a McKusick number is included that allows the reader to immediately access information about the disorder using the Online Mendelian Inheri- tance in Man Internet site (http://www.ncbi.nlm.nih.gov/omim/). An effective way to use this PreTest is to allow yourself 1 minute to answer each question in a given chapter. As you proceed, indicate your answer beside each question. By following this suggestion, you approxi- mate the time limits imposed by the USMLE Step 1 examination. After you finish going through the questions in the section, spend as much time as you need verifying your answers and carefully reading the explanations provided. Pay special attention to the explanations for the questions you answered incorrectly—but read every explanation. The authors of this material have designed the explanations to reinforce and supplement the information tested by the questions. If you feel you need further informa- tion about the material covered, consult and study the text or online refer- ences indicated. The high-yield facts in this book are provided to facilitate rapid review of biochemistry and genetics. Key concepts and diagrams are arranged before each section, and it is anticipated that the reader will use the key concepts as a “memory jog” before proceeding through the questions. x Copyright © 2007 by The McGraw-Hill Companies, Inc. Click here for terms of use. Note Concerning Disease Examples This book provides over 130 disease examples (see Appendix) to illustrate the broad application of biochemistry and genetics to medicine. These include more common chromosomal or multifactorial disorders (Down syndrome, cleft palate, diabetes mellitus) that have incidences ranging from 1 in 200 to 1 in 2000–3000 to less common single gene disorders (cystic fibrosis, glycogen storage diseases) with incidences of 1 in 1600 to 1 per million individuals).