1. Lecture 3 THE CHEMISTRY OF LIVING THINGS

2. Table 2.1 III. Atoms Combine to Form Molecules C. Three types of Bonds

3. Figure 2.6 III. Atoms Combine to Form Molecules Covalent Bond

4. Covalent Bonds

5. Figure 2.7 III. Atoms Combine to Form Molecules Ionic Bond

6. Ionic Bonds

7. Hydrogen Bonds

8. IV. Elements of Living Organisms Table 2.2

9. A. Water molecules are polar B. Water is liquid at body temperature C. Water can absorb & hold heat energy V. Life Depends on Water

10. D. Two Important Biological Functions of Water 1. Water is the biological Solvent 2. Water helps regulate body temperature V. Life Depends on Water

11. Water Keeps Ions in Solution Figure 2.9

12. A. Acids are proton (hydrogen ion) donors, 1. Bases accept hydrogen ions 1. Bases accept hydrogen ions B. pH Scale = hydrogen ion concentration C. Buffers: minimize pH change 1. Carbonic acid & bicarbonate act as one of body’s most important buffer pairs VI. The Importance of Hydrogen Ions

13. The pH Scale Figure 2.11

14. A. Carbon, the building block of living things: 1. Comprises 18% of body by weight 2. Forms four covalent bonds 3. Can form single or double bonds 4. Can build micro- or macromolecules VII. The Organic Molecules of Living Organisms

15. Carbon Can Bond in Many Ways Figure 2.13

16. VIII. Making & Breaking Biological Macromolecules Figure 2.14

17. A. Dehydration synthesis 1. Removes equivalent of a water molecule to link molecular units 2. Requires energy B. Hydrolysis 1. Adds the equivalent of a water molecule to break apart macromolecules 2. Releases energy VIII. Making & Breaking Biological Macromolecules

18. IX. Carbohydrates Figure 2.15

19. A. Oligosaccharides: short chains of monosaccharides Disaccharides: sucrose, maltose, lactose IX. Carbohydrates

20. B. Polysaccharides: thousands of monosaccarides joined in chains & branches 1. Starch: made in plants; stores energy 2. Glycogen: made in animals; stores energy 3. Cellulose: undigestible polysaccharide made in plants for structural support IX. Carbohydrates

21. A. Triglycerides: energy storage molecules Ex: Fatty acids: saturated and unsaturated B. Phospholipids: cell membranes C. Steroids: carbon-based ring structures Ex: Cholesterol: used in making estrogen and testosterone X. Lipids: Insoluble in Water

22. Triglycerides Figure 2.17

23. Phospholipids & Steroids Figure 2.18 Figure 2.19

24. Protein Structure Figure 2.18

25. A. Structure 1. Primary: amino acid sequence 2. Secondary: describes chain’s orientation in space; e.g., alpha helix, beta sheet XI. Proteins: Complex Structures Constructed of Amino Acids

26. A. Structure 3. Tertiary: describes three-dimensional shape created by disulfide and hydrogen bonds Creates polar and nonpolar areas in molecule 4. Quaternary: describes proteins in which two or more tertiary protein chains are associated XI. Proteins: Complex Structures Constructed of Amino Acids

27. Protein Structure Figure 2.18

28. XI. Proteins: Complex Structures Constructed of Amino Acids

29. A. Enzymes: 1. proteins 2. function as catalysts 3 facilitate chemical reactions B. The functional shape of an enzyme is dependent on: 1. temperature of reaction medium 2. pH 3. ion concentration 4. presence of inhibitors XII. Enzyme Function

30. A. Functions 1. Store genetic information 2. Provide information used in making proteins B. Structure 1. Nucleotides consist of a phosphate group, a sugar, and a nitrogenous base 2. DNA structure is a double helix: two associated strands of nucleic acids 3. RNA is a single-stranded molecule XII. Structure and Function of Nucleic Acids

31. C. DNA: double-stranded 1. Sugar: deoxyribose 2. Nitrogenous bases: adenine, thymine, cytosine, guanine 3. Pairing: adenine-thymine and cytosine- guanine XII. Structure and Function of Nucleic Acids

32. D. RNA: single-stranded 1. Sugar: ribose 2. Nitrogenous bases: adenine, uracil, cytosine, guanine 3. Pairing: adenine-uracil, cytosine-guanine XII. Structure and Function of Nucleic Acids

33. Structure and Function of Adenosine Triphosphate (ATP) Figure 2.26