1. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb PowerPoint ® Lecture Slides prepared by Vince Austin, University of Kentucky 2 Chemistry Comes Alive Part B

2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Biochemistry  Organic compounds  Contain carbon, are covalently bonded, and are often large  Inorganic compounds  Do not contain carbon  Water, salts, and many acids and bases

3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Properties of Water  High heat capacity – absorbs and releases large amounts of heat before changing temperature  High heat of vaporization – changing from a liquid to a gas requires large amounts of heat  Polar solvent properties – dissolves ionic substances, forms hydration layers around large charged molecules, and serves as the body’s major transport medium

4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Properties of Water  Reactivity – is an important part of hydrolysis and dehydration synthesis reactions  Cushioning – resilient cushion around certain body organs

5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Acids and Bases  Acids release H + and are therefore proton donors HCl  H + + Cl –  Bases release OH – and are proton acceptors NaOH  Na + + OH –

6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Acid-Base Concentration (pH)  Acidic solutions have higher H + concentration and therefore a lower pH  Alkaline solutions have lower H + concentration and therefore a higher pH  Neutral solutions have equal H + and OH – concentrations

7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Acid-Base Concentration (pH)  Acidic: pH 0–6.99  Basic: pH 7.01–14  Neutral: pH 7.00 Figure 2.12

8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Buffers  Systems that resist abrupt and large swings in the pH of body fluids  Carbonic acid-bicarbonate system  Carbonic acid dissociates, reversibly releasing bicarbonate ions and protons  The chemical equilibrium between carbonic acid and bicarbonate resists pH changes in the blood

9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Organic Compounds  Molecules unique to living systems contain carbon and hence are organic compounds  They include:  Carbohydrates  Lipids  Proteins  Nucleic Acids

10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Carbohydrates Figure 2.13a  Contain carbon, hydrogen, and oxygen  Their major function is to supply a source of cellular food  Examples:  Monosaccharides or simple sugars

11. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Carbohydrates Figure 2.13b  Disaccharides or double sugars

12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Carbohydrates Figure 2.13c  Polysaccharides or polymers of simple sugars

13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lipids  Contain C, H, and O, but the proportion of oxygen in lipids is less than in carbohydrates  Examples:  Neutral fats or triglycerides  Phospholipids  Steroids

14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Neutral Fats (Triglycerides) Figure 2.14a  Composed of three fatty acids bonded to a glycerol molecule

15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Other Lipids Figure 2.14b  Phospholipids – modified triglycerides with two fatty acid groups and a phosphorus group

16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Other Lipids Figure 2.14c  Steroids – flat molecules with four interlocking hydrocarbon rings

17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Representative Lipids Found in the Body  Neutral fats – found in subcutaneous tissue and around organs  Phospholipids – chief component of cell membranes  Steroids – cholesterol, sex hormones, and adrenal cortical hormones  Fat-soluble vitamins – vitamins A,D, E, and K  Lipoproteins – transport fatty acids and cholesterol in the bloodstream

18. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Amino Acids  Building blocks of protein, containing an amino group and a carboxyl group  Amino acid structure

19. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Amino Acids Figure 2.15a-c

20. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Protein Figure 2.16  Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds

21. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Structural Levels of Proteins  Primary – amino acid sequence  Secondary – alpha helices or beta pleated sheets  Tertiary – superimposed folding of secondary structures  Quaternary – polypeptide chains linked together in a specific manner

22. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Structural Levels of Proteins Figure 2.17a-c

23. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Structural Levels of Proteins Figure 2.17d, e

24. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous and Globular Proteins  Fibrous proteins  Extended and strandlike proteins  Examples: keratin, elastin, collagen, and certain contractile fibers  Globular proteins  Compact, spherical proteins with tertiary and quaternary structures  Examples: antibodies, hormones, and enzymes

25. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Protein Denuaturation Figure 2.18a  Reversible unfolding of proteins due to drops in pH and/or increased temperature

26. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Protein Denuaturation Figure 2.18b  Irreversibly denatured proteins cannot refold and are formed by extreme pH or temperature changes

27. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Characteristics of Enzymes  Most are globular proteins that act as biological catalysts  Holoenzymes consist of an apoenzyme (protein) and a cofactor (usually an ion)  Enzymes are chemically specific  Frequently named for the type of reaction they catalyze  Enzyme names usually end in -ase  Lower activation energy

28. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Characteristics of Enzymes Figure 2.19

29. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Mechanism of Enzyme Action  Enzyme binds with substrate  Product is formed at a lower activation energy  Product is released

30. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Enzyme- substrate complex (E–S) 1 2 3 Internal rearrangements leading to catalysis Free enzyme (E) Active site Enzyme (E) Substrates (s) Amino acids H20H20 Peptide bond Dipeptide product (P) Mechanism of Enzyme Action Figure 2.20

31. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nucleic Acids  Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus  Their structural unit, the nucleotide, is composed of N-containing base, a pentose sugar, and a phosphate group  Five nitrogen bases contribute to nucleotide structure – adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U)  Two major classes – DNA and RNA

32. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Deoxyribonucleic Acid (DNA)  Double-stranded helical molecule found in the nucleus of the cell  Replicates itself before the cell divides, ensuring genetic continuity  Provides instructions for protein synthesis

33. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Structure of DNA Figure 2.21a

34. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Structure of DNA Figure 2.21b

35. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Ribonucleic Acid (RNA)  Single-stranded molecule found in both the nucleus and the cytoplasm of a cell  Uses the nitrogenous base uracil instead of thymine  Three varieties of RNA: messenger RNA, transfer RNA, and ribosomal RNA

36. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Adenosine Triphosphate (ATP)  Source of immediately usable energy for the cell  Adenine-containing RNA nucleotide with three phosphate groups

37. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Adenosine Triphosphate (ATP) Figure 2.22

38. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings How ATP Drives Cellular Work Figure 2.23