Porth's Essentials of Pathophysiology, 4e

ur hereditary information is stored in the chemi- cal structure of deoxyribonucleic acid (DNA), an extremely stable macromolecule. Deoxyribonucleic acid contains within its structure the basic information needed to direct the function of our cells, influence our appearance, and how we respond to our environment, and serve as the unit of inheritance that is passed on from generation to generation. Our DNA can also influ- ence disease susceptibility and how we react to drugs. A gene is a locatable segment or segments of DNA sequence that encodes a set of functional products, typi- cally proteins. Genetics is the study of genes. An under- standing of the role that genetics plays in the pathogenesis of disease has expanded greatly over the past century. It is now apparent that many diseases, including cancer, diabetes, and cardiovascular diseases, have a genetic component. At the same time, genetic advances have led to new methods for early detection and more effec- tive treatment. Advances in immunogenetics have made compatible blood transfusion and organ transplants a reality, and recombinant DNA technology has provided the methods for producing human insulin, growth hor- mone, and clotting factors. Perhaps the most extensive use of gene technology involved the Human Genome Project, begun in 1990 and completed in 2003. The goal of this international effort was to sequence the human genome and map all of its genes. This chapter includes discussions of genetic control of cell function, chromosomes, patterns of inheritance, and gene technology. O Genetic Control of Cell Function and Inheritance 5 C h a p t e r

Genetic Control of Cell Function DNA Structure and Function

Double Helix and Base Pairing Packaging of DNA Genetic Code DNA Repair

Genetic Variability Mitochondrial DNA From Genes to Proteins

RNA Structure and Function Transcription Translation Regulation of Gene Expression

Chromosomes

Cell Division Chromosome Structure

Patterns of Inheritance Definitions Mendel Laws Genetic Imprinting Gene Technology Gene Mapping

The Human Genome Project Genetic Mapping Methods Haplotype Mapping Recombinant DNA Technology Gene Isolation and Cloning Pharmaceutical Applications DNA Fingerprinting Gene Therapy RNA Interference Technology

Genetic Control of Cell Function

The genetic instructions for protein synthesis are encoded in the DNA contained in the cell nucleus. Because of its stable structure, the genetic information carried in DNA can survive the many stages of cell divi- sion involved in the day-to-day process of cell renewal and tissue growth. Its stable structure also allows the information to survive the many processes of reduction

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