1. Chemistry of Anatomy and Physiology

2. Atoms Smallest unit of an element Subatomic particles Protons: (+) charge Neutrons: neutral Electrons: (-) charge Atoms Smallest unit of an element Subatomic particles Protons: (+) charge Neutrons: neutral Electrons: (-) charge Figure 2-1

3. Structure of an atom Nucleus Protons Neutrons Electron Cloud Structure of an atom Nucleus Protons Neutrons Electron Cloud Figure 2-2(b)

4. Structure of atom Atomic number Equals number of protons Atomic mass Equals protons + neutrons Isotopes of element Reflects number of neutrons Atomic weight Averages isotope abundance Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

5. Structure of atom Electrons surround nucleus Electrons organized in shells (sublevels) The outer shell determines chemical properties Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

6. Key Note All matter is composed of atoms in various combinations. Their interactions establish the foundations of physiology at the cellular level. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

8. Chemical Bonds and Compounds Atoms bond in chemical reactions Electrons are gained, lost, or shared Molecules or compounds result Compounds contain several elements Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

9. Ionic Bonds Atoms gain or lose electrons Charged atoms are ions Ions bear (+) or (-) charge Cations have (+) charge Anions have (-) charge Cations and anions attract Ions form bonds Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

10. Table 2-2

11. Covalent bonds Some atoms share electrons Shared electrons complete outer shell Sharing atoms bond covalently Single covalent bond One shared electron Double covalent bond Two shared electrons Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

12. Figure 2-5

13. Nonpolar and Polar Covalent Bonds Equal electron sharing Nonpolar covalent bonds Example: carbon-carbon bonds Non-equal electron sharing Polar covalent bonds Example: oxygen-hydrogen bonds Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

14. Hydrogen bonds Weak attractive force Between 2 neighboring atoms A polar-bonded hydrogen, and A polar-bonded oxygen or nitrogen For example, between water molecules Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

15. Figure 2-6

16. A chemical “shorthand” Simplified descriptions of: Compounds Structures Reactions Ions Abbreviations of elements Abbreviations of molecules Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

17. Basic Energy Concepts Work—movement or change in matter’s physical structure E.g., running, synthesis Energy—ability to do work Kinetic energy Potential energy Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

18. Basic Energy Concepts (continued) Potential energy—stored energy E.g., leopard lurks in a tree Kinetic energy—energy of movement E.g., leopard pounces on prey Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

19. 3 types of reactions Decomposition—breaks molecule into smaller pieces Synthesis—assembles smaller pieces into larger one Exchange—shuffles pieces between molecules Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

20. Decomposition Reactions In chemical notation: AB A + B Releases covalent bond energy Hydrolysis—Decomposition reaction with HOH E.g., food digestion Catabolism—Sum of all the body’s decomposition reactions Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

21. Synthesis Reactions In chemical notation: A + B AB Absorbs energy Formation of new bonds Dehydration synthesis Removal of HOH between molecules Anabolism—Sum of the body’s synthesis reactions

22. Exchange Reaction In chemical notation: AB + CD AC + BD Decomposition and synthesis Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Reversible Reactions A + B AB Equilibrium—Condition when the forward and reverse reactions occur at the same rate

23. Exergonic—Reactions that release energy E.g., decomposition reactions Endergonic—Reactions that consume energy E.g., synthesis reactions Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

24. Key Terms Nutrients Essential elements and molecules obtained from the diet Metabolites Molecules synthesized or broken down by chemical reactions inside the body Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

25. Inorganic Smaller molecules such as water and oxygen that lack carbon and hydrogen Organic Larger molecules such as sugars, proteins, and fats composed largely of carbon and hydrogen Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

26. Carbon Dioxide (CO 2 ) Gas produced by cellular metabolism and released into the atmosphere via the lungs Oxygen (O 2 ) Atmospheric gas consumed by cells in order to produce energy Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

27. Water and its properties Most important body chemical Excellent solvent High heat capacity Essential chemical reactant Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

28. Key Note Water accounts for most of your body weight. Proteins, key components of cells, and nucleic acids, which control cells, work only in solution. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

30. pH A measure of hydrogen ion concentration in a solution Neutral solution—pH = 7 Acidic solution—pH below 7 Basic solution—pH above 7 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

31. Figure 2-9

32. Buffers Maintain pH within normal limits (pH 7.35 to pH 7.45) Release hydrogen ions if body fluid is too basic Absorb hydrogen ions if body fluid is too acidic Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

33. Organic Compounds Contain carbon, hydrogen, and usually oxygen Important classes of organic compounds include: Carbohydrates Lipids Proteins Nucleic acids Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

34. Carbohydrates Most important energy source for metabolism Three major types Monosaccharides (E.g., glucose) Disaccharides (E.g., sucrose) Polysaccharides (E.g., glycogen) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

35. Figure 2-10

36. Lipids Water-insoluble Four important classes Fatty acids Fats Steroids Phospholipids Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

37. Proteins Most abundant organic component in human body About 100,000 different proteins Contain carbon, nitrogen, oxygen, hydrogen, and a bit of sulfur Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

38. Proteins play vital roles Support Movement Transport Buffering Regulation Defense Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Peptide bonds join amino acids into long strings

39. Protein Structure “R” groups interact with their neighbors and with solvent Amino acid chain folds and twists into complex shape Final shape determines function High fever distorts shape Distorted proteins don’t work Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

40. Enzyme Function Substrates (reactants) bind to active site on enzyme surface Binding lowers activation energy needed for reaction Substrates react to form product Product is released from enzyme surface Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

41. Figure 2-18

42. Nucleic Acids Large molecules Built from atoms of C, H, O, N, and P (What are these elements?) Store and process molecular information Two classes of nucleic acid DNA (deoxyribonucleic acid) RNA (ribonucleic acid) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

43. Structure of Nucleic Acids Nucleotides contain a sugar, a phosphate, and a base Sugar-phosphate bonds link nucleotides in long strands Hydrogen bonds hold two DNA strands in a double helix Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings