1. CHEMISTRY

2. Decomposition—breaks molecules into smaller pieces Synthesis—build smaller pieces into larger one Exchange—shuffles pieces between molecules CHEMICAL REACTIONS Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

3. Decomposition Reactions To keep it simple: AB A + B Releases energy (from a covalent bond ) Hydrolysis—Decomposition reaction with water E.g., food digestion Catabolism—Sum of all the body’s decomposition reactions CHEMICAL REACTIONS Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

4. Synthesis Reactions It’s simply this: A + B AB Usually requires energy Forms new bonds Dehydration synthesis Removal of HOH between molecules…so it makes water… Anabolism—Sum of the body’s synthesis reactions CHEMICAL REACTIONS Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

5. Exchange Reaction In chemical notation: AB + CD AC + BD Decomposition and synthesis CHEMICAL REACTIONS Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

6. Reversible Reactions A + B AB Equilibrium—Condition when the forward and reverse reactions occur at the same rate CHEMICAL REACTIONS Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

7. An exergonic reaction is one in which the bond being broken has more energy than the one formed so that extra energy is released, usually as heat (occurs during catabolism of food molecules). An endergonic reaction is just the opposite and thus requires that energy be added, usually from a molecule called ATP, to form a bond, as in bonding amino acid molecules together to form proteins. ENERGY TRANSFER IN CHEMICAL REACTIONS

8. Key Note When energy is exchanged, heat is produced. Heat raises local temperatures, but cells cannot capture it or use it to perform work. CHEMICAL REACTIONS Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

9. 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 INORGANIC VERSUS ORGANIC Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

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

11. Inorganic Acids and Bases Acid—Releases hydrogen ions (H + ) into solution E.g., HCl H + + Cl - Base—Removes hydrogen ions from solution E.g., NaOH + H + Na + + H0H INORGANIC COMPOUNDS Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

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

13. pH and Hydrogen Ion Concentration INORGANIC COMPOUNDS Figure 2-9

14. 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 INORGANIC COMPOUNDS Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

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

16. Organic Chemical Building Blocks SUMMARY OF BODY CHEMISTRY

17. Carbohydrates provide most of the energy needed for life and include sugars, starches, glycogen, and cellulose. Some carbohydrates are converted to other substances which are used to build structures and to generate ATP. Other carbohydrates function as food reserves. Carbohydrates are divided into three major groups based on their size: monosaccharides, disaccharides, and polysaccharides CARBOHYDRATES

18. LIPIDS Triglycerides are the most plentiful lipids in the body and provide protection, insulation, and energy (both immediate and stored). Phospholipids are important membrane components. Steroids include Sex hormones Bile salts Some vitamins Cholesterol

19. Nucleic acids are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. Deoxyribonucleic acid (DNA) forms the genetic code inside each cell and thereby regulates most of the activities that take place in our cells throughout a lifetime. Ribonucleic acid (RNA) relays instructions from the genes in the cell’s nucleus to guide each cell’s assembly of amino acids into proteins by the ribosomes. The basic units of nucleic acids are nucleotides, composed of a nitrogenous base, a pentose sugar, and a phosphate group. DNA AND RNA

20. Temporary molecular storage of energy as it is being transferred from exergonic catabolic reactions to cellular activities ADENOSINE TRIPHOSPHATE (ATP)