1. Principles of Anatomy and Physiology Thirteenth Edition Chapter 2 The Chemical Level of Organization Copyright © 2012 by John Wiley & Sons, Inc. Gerard J. Tortora Bryan H. Derrickson

2. (a) Electron cloud model Protons (p + ) (b) Electron shell model Neutrons (n 0 ) Electrons (e – ) Nucleus

3. First electron shell Second electron shell Third electron shell Fourth electron shell Fifth electron shell Hydrogen (H) Atomic number = 1 Mass number = 1 or 2 Atomic mass = 1.01 Carbon (C) Atomic number = 6 Mass number = 12 or 13 Atomic mass = 12.01 Nitrogen (N) Atomic number = 7 Mass number = 14 or 15 Atomic mass = 14.01 Oxygen (O) Atomic number = 8 Mass number = 16, 17, or 18 Atomic mass = 16.00 Sodium (Na) Atomic number = 11 Mass number = 23 Atomic mass = 22.99 Chlorine (Cl) Atomic number = 17 Mass number = 35 or 37 Atomic mass = 35.45 Potassium (K) Atomic number = 19 Mass number = 39, 40, or 41 Atomic mass = 39.10 Iodine (I) Atomic number = 53 Mass number = 127 Atomic mass = 126.90 1p + 6p + 6n 0 7p + 7n 0 8p + 8n 0 11p + 12n 0 17p + 18n 0 19p + 20n 0 53p + 74n 0 Atomic number = number of protons in an atom Mass number = number of protons and neutrons in an atom (boldface indicates most common isotope) Atomic mass = average mass of all stable atoms of a given element in daltons

4. Unpaired electron (a) Oxygen molecule (O 2 ) (b) Superoxide free radical (O 2 – )

5. Electron donated (a) Sodium: 1 valence electron AtomIon Na

6. Electron accepted (b) Chlorine: 7 valence electrons AtomIon Cl

7. (c) Ionic bond in sodium chloride (NaCl) Na Cl

8. (d) Packing of ions in a crystal of sodium chloride Na + Cl –

9. Hydrogen atomsHydrogen molecule DIAGRAMS OF ATOMIC AND MOLECULAR STRUCTURE STRUCTURAL FORMULA MOLECULAR FORMULA (a)

10. Oxygen atomsOxygen molecule DIAGRAMS OF ATOMIC AND MOLECULAR STRUCTURE STRUCTURAL FORMULA MOLECULAR FORMULA (b)

11. Nitrogen atomsNitrogen molecule DIAGRAMS OF ATOMIC AND MOLECULAR STRUCTURE STRUCTURAL FORMULA MOLECULAR FORMULA (c)

12. Carbon atomMethane molecule DIAGRAMS OF ATOMIC AND MOLECULAR STRUCTURE STRUCTURAL FORMULA MOLECULAR FORMULA Hydrogen atoms (d)

13. Oxygen atomWater molecule DIAGRAMS OF ATOMIC AND MOLECULAR STRUCTURE STRUCTURAL FORMULA MOLECULAR FORMULA Hydrogen atoms ++ ++ –– (e)

14. Hydrogen bonds ++ ++ ––

15. ReactantsProducts 2 H 2 O2 H 2 O2O2

16. Activation energy Energy absorbed to start reaction Energy released as new bonds form Energy of products Energy of reactants Potential energy Progress of the reaction

17. Activation energy needed without catalyst Potential energy Progress of the reaction Activation energy needed with catalyst Energy of products Energy of reactants

18. Crystal of NaCl Hydrated chloride ion Hydrated sodium ion Water molecule Na + Cl – Na + Cl – ++ –– ++ ++ ++ ++ ++ –– –– –– –– –– –– –– –– O HH O H H O HH

19. (a) Acid HCl (b) Base(c) Salt KOHKCl H+H+ Cl – K+K+ OH – K+K+ Cl –

20. [OH – ] (moles/liter) [H + ] pH INCREASINGLY ACIDIC NEUTRAL INCREASINGLY BASIC (ALKALINE)

21. All atoms written outStandard shorthand

22. Deoxyribose Ribose (a) Pentoses

23. GlucoseFructose (b) Hexoses Galactose

24. Glucose (C 6 H 12 O 6 ) Sucrose (C 12 H 22 O 11 ) (a) Dehydration synthesis and hydrolysis of sucrose Dehydration synthesis Fructose (C 6 H 12 O 6 ) Hydrolysis Water

25. Galactose (b) Lactose Glucose

26. (c) Maltose Glucose

27. Glucose monomer

28. Palmitic acid (C 15 H 31 COOH) (Saturated) Oleic acid (C 17 H 33 COOH) (Monounsaturated) (a) Structures of saturated and unsaturated fatty acids

29. Palmitic acid (C 15 H 31 COOH) (b) Dehydration synthesis involving glycerol and a fatty acid Fatty acid molecule Glycerol molecule

30. Palmitic acid (C 15 H 31 COOH) + (Saturated) (c) Triglyceride (fat) molecule Stearic acid (C 17 H 35 COOH) + (Saturated) Oleic acid (C 17 H 33 COOH) + (Monounsaturated) Ester linkage

31. (c) Arrangement of phospholipids in a portion of a cell membrane (a) Chemical structure of a phospholipid Polar head (b) Simplified way to draw a phospholipid Nonpolar tails Polar head Phosphate group Nonpolar tails Polar heads Nonpolar tails Cell membrane

32. Cholesterol Estradiol (an estrogen or female sex hormone) Testosterone (a male sex hormone) Cortisol Hydroxyl group 4 rings Hydrocarbon tail

33. (a) Nonionized form of an amino acid Amino (base) group Side chain Carboxyl (acid) group

34. (b) Doubly ionized form of an amino acid

35. (c) Representative amino acids TyrosineLysine GlycineCysteine

36. GlycineAlanineGlycylalanine (a dipeptide) Water Dehydration synthesis Hydrolysis Peptide bond

37. Polypeptide chain (a) Primary structure (amino acid sequence) Amino acids Peptide bond

38. Alpha helix (b) Secondary structure (twisting and folding of neighboring amino acids, stabilized by hydrogen bonds) Hydrogen bond Beta pleated sheet

39. (c) Tertiary structure (three- dimensional shape of polypeptide chain) (d) Quaternary structure (arrangement of two or more polypeptide chains)

40. Enzyme Sucrase Active site of enzyme Substrates Sucrose and Water Products Glucose Fructose Enzyme and substrate come together at active site of enzyme, forming an enzyme–substrate complex Enzyme catalyzes reaction and transforms substrate into products When reaction is complete, enzyme is unchanged and free to catalyze same reaction again on a new substrate (a) Mechanism of enzyme action 1 3 2 H2OH2O

41. Substrate (glucose) (b) Molecular model of enzyme and substrate uncombined (left) and enzyme–substrate complex (right) Enzyme (hexokinase) Substrate Enzyme

42. a) Components of nucleotides (b) Portion of a DNA molecule Phosphate group Deoxyribose group Hydrogen bond Strand 2Strand 1 = Adenine = Guanine = Thymine = Cytosine Cytosine (C) Guanine (G) Thymine (T)Adenine (A) Deoxyribose sugar Phosphate group Key to bases:

43. Adenine Adenosine Ribose Phosphate groups Adenosine diphosphate (ADP) Adenosine triphosphate (ATP)