1. 2-1 Anatomy and Physiology, Sixth Edition Rod R. Seeley Idaho State University Trent D. Stephens Idaho State University Philip Tate Phoenix College Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. *See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Chapter 02 Lecture Outline *

2. 2-2 Chapter 2 The Chemical Basis of Life

3. 2-3 Basic Chemistry Matter, Mass, and Weight –Matter: Anything that occupies space and has mass –Mass: The amount of matter in an object –Weight: The gravitational force acting on an object of a given mass Elements and Atoms –Elements: The simplest type of matter with unique chemical properties –Atoms: Smallest particle of an element that has chemical characteristics of that element

4. 2-4 Atomic Structure Atoms: composed of subatomic particles –Neutrons: no electrical charge –Protons: positive charge –Electrons: negative charge Nucleus –Formed by protons and neutrons –Most of volume of atom occupied by electrons

5. 2-5 Atomic Number and Mass Number Atomic Number: Equal to number of protons in each atom which equals the number of electrons Mass Number: Number of protons plus number of neutrons

6. 2-6 Isotopes and Atomic Mass Isotopes: Two or more forms of same element with same number of protons and electrons but different neutron number –3 types of hydrogen –Denoted by using symbol of element preceded by mass number as 1 H, 2 H, 3 H Atomic Mass: Average mass of naturally occurring isotopes

7. 2-7 Electrons and Chemical Bonding Ion: When an atom loses or gains electrons and become charged –Cation: Positively charged ion –Anion: Negatively charged ion Ionic Bonding –Cations and anions are attracted to each other

8. 2-8 Covalent Bonding Atoms share one or more pairs of electrons –Single covalent: Electron pair between 2 atoms –Double covalent: Two atoms share 4 electrons Nonpolar covalent: Electrons shared equally Polar covalent: Electrons not shared equally

9. 2-9 Molecules and Compounds Molecules: Two or more atoms chemically combine to form and independent unit –Example: Water Compounds: A substance composed of two or more different types if atoms chemically combined –Example: Hydrogen Molecule Molecular Mass: Determined by adding up atomic masses of its atoms or ions –Example: NaCl (22.99 + 35.45)

10. 2-10 Intermolecular Forces Result from weak electrostatic attractions between oppositely charged parts or molecules, or between ions and molecules Weaker than forces producing chemical bonding

11. 2-11 Intermolecular Forces Hydrogen Bonds –Water: Positively charged hydrogen atoms bond with negatively charged oxygen atoms of other water molecules –Important role in determining shape of complex molecules

12. 2-12 Intermolecular Forces Solubility: Ability of one substance to dissolve in another –Example: Sugar dissolves in water Dissociation or Separation –Ionic compounds –Cations are attracted to negative end and anions attracted to positive end of water molecules

13. 2-13 Intermolecular Forces Electrolytes: Cations (+) and anions (-) that dissociate in water –Capacity to conduct an electric current –Currents can be detected by electrodes Nonelectrolytes: Molecules that do not dissociate form solutions that do not conduct electricity

14. 2-14 Chemical Reactions Chemical Reactions: Atoms, ions, molecules or compounds interact to form or break chemical bonds –Metabolism: All anabolic and catabolic reactions in the body Catabolism: Decomposition reactions –Hydrolysis: Reactions that use water Anabolism: Growth, maintenance, and repair of the body in synthesis reactions –Produce molecules characteristic of life: ATP, proteins, carbohydrates, lipids, and nucleic acids

15. 2-15 Synthesis and Decomposition Reactions Synthesis Reactions –Two or more reactants chemically combine to form a larger product –Anabolism: All body’s synthesis reactions Decomposition Reactions –Reverse of synthesis reactions –Catabolism: Reactions of decomposition in body

16. 2-16 Oxidation-Reduction Reactions Oxidation –Loss of an electron by an atom Reduction –Gain of an electron by an atom Oxidation-Reduction Reactions –The complete or partial loss of an electron by one atom is accompanied by the gain of that electron by another atom

17. 2-17 Energy Energy: The capacity to do work –Potential Energy: Stored energy –Kinetic Energy: Does work and moves matter –Mechanical Energy: Energy resulting from the position or movement of objects –Chemical Energy: Form of potential energy in the chemical bonds of a substance –Heat Energy: Energy that flows between objects of different temperatures

18. 2-18 Energy and Chemical Reactions

19. 2-19 Speed of Chemical Reactions Activation Energy: Minimum energy reactants must have to start a chemical reaction –Catalysts: Substances that increase the rate of chemical reactions without being permanently changed or depleted –Enzymes: Increase the rate of chemical reactions by lowering the activation energy necessary for reaction to begin

20. 2-20 Activation Energy and Enzymes

21. 2-21 Chemistry Inorganic Chemistry: Generally substances that do not contain carbon –Water –Oxygen Organic Chemistry: Study of carbon- containing substances

22. 2-22 Water Inorganic Stabilizes body temperature Protection Necessary for many chemical reactions of life Mixing Medium –Mixture: Substance physically but not chemically combined Solution: Liquid, gas, or solid uniformly distributed –Solvent: What dissolves the solute –Solute: What is to be dissolved

23. 2-23 Acids and Bases; Salts and Buffers Acid: A proton donor or any substance that releases hydrogen ions Bases: A proton acceptor or any substance that binds to or accepts hydrogen ions Salts: A cation consisting of other than a hydrogen ion and other than an anion or hydroxide ion Buffers: A solution of a conjugate acid-base pair in which acid and base component occur in similar concentrations

24. 2-24 The pH Scale Refers to the Hydrogen ion concentration in a solution –Neutral: pH of 7 or equal hydrogen and hydroxide ions –Acidic: a greater concentration of hydrogen ions –Alkaline or basic: a greater concentration of hydroxide ions

25. 2-25 Organic Chemistry Carbohydrates –Composed of carbon, hydrogen, oxygen Lipids –Composed mostly of carbon, hydrogen, oxygen Proteins –Composed of carbon, hydrogen, oxygen,nitrogen Nucleic Acids: DNA and RNA –Composed of carbon, hydrogen, oxygen, nitrogen, phosphorus Adenosine Triphosphate (ATP) –Composed of adenosine and three phosphate groups

26. 2-26 Carbohydrates Monosaccharides –Simple sugars: glucose, fructose, galactose Disaccharides –Two simple sugars bound together by dehydration: sucrose, lactose, maltose Polysaccharides –Long chains of many monosaccharides: glycogen in animals; starch and cellulose in plants

27. 2-27 Monosaccharides

28. 2-28 Disaccharide and Polysaccharide

29. 2-29 Lipids Lipids: Can be dissolved in nonpolar organic solvents as alcohol or acetone but relatively insoluble in water –Fats: Ingested and broken down by hydrolysis –Triglycerides: composed of glycerol and fatty acids –Phospholipids: Important structural component of cell membranes –Eicosanoids: Derived from fatty acids –Steroids: Cholesterol, bile salts, estrogen, testosterone –Fat-soluble Vitamins

30. 2-30 Phospholipids

31. 2-31 Steroids

32. 2-32 Proteins Amino acids: The building blocks of protein Peptide bonds: Covalent bonds formed between amino acids during protein synthesis Structure –Primary, secondary, tertiary, quartenary Enzymes: Protein catalysts –Lock-and-key model –Active site –Cofactors –Coenzymes

33. 2-33 Peptide Bonds

34. 2-34 Protein Structure and Enzyme Action

35. 2-35 Nucleic Acids: DNA and RNA DNA: Deoxyribonucleic acid –Genetic material of cells copied from one generation to next –Composed of 2 strands of nucleotides Each nucleotide contains one of the organic bases of adenine or guanine which are purines and thymine or cystosine which are pyrimidines RNA: Ribonucleic acid –Similar to a single strand of DNA Four different nucleotides make up organic bases except thymine is replaced with uracil (pyrimidine)

36. 2-36 DNA Structure

37. 2-37 Nucleotides and Nitrogenous Bases

38. 2-38 Adenosine Triphosphate (ATP) Energy currency of the body Provides energy for other chemical reactions as anabolism or drive cell processes as muscle contraction All energy-requiring chemical reactions stop when there is inadequate ATP