Molecules of Life

1. Molecules of Life Chapter 3

2. 3.1 Molecules of Life • Molecules of life are synthesized by living cells • Carbohydrates • Lipids • Proteins • Nucleic acids

3. Structure to Function • Molecules of life differ in three-dimensional structure and function • Carbon backbone • Attached functional groups • Structures give clues to how they function

4. Organic Compounds • Consist primarily of carbon and hydrogen atoms • Carbon atoms bond covalently with up to four other atoms, often in long chains or rings • Functional groups attach to a carbon backbone • Influence organic compound’s properties

5. An Organic Compound: Glucose • Four models

6. Functional Groups

7. In alcohols (e.g., sugars, amino acids); water soluble hydroxyl methyl In fatty acid chains; insoluble in water carbonyl In sugars, amino acids, nucleotides; water soluble. An aldehyde if at end of a carbon backbone; a ketone if attached to an interior carbon of backbone (aldehyde) (ketone) carboxyl In amino acids, fatty acids, carbohydrates; water soluble. Highly polar; acts as an acid (releases H+) (non-ionized) (ionized) Fig. 3.3, p. 36

8. amino In amino acids and certain nucleotide bases; water soluble, acts as a weak base (accepts H+) (non-ionized) (ionized) phosphate In nucleotides (e.g., ATP), also in DNA, RNA, many proteins, phospholipids; water soluble, acidic icon Fig. 3.3, p. 36

9. Functional Groups: The Importance of Position

10. one of the estrogens testosterone Fig. 3.4, p. 37

11. Animation: Functional group CLICK HERE TO PLAY

12. Processes of Metabolism • Cells use energy to grow and maintain themselves • Enzyme-driven reactions build, rearrange, and split organic molecules

13. Building Organic Compounds • Cells form complex organic molecules • Simple sugars → carbohydrates • Fatty acids → lipids • Amino acids → proteins • Nucleotides → nucleic acids • Condensation combines monomers to form polymers

14. What Cells Do to Organic Compounds

15. Condensation and Hydrolysis

16. enzyme action at functional groups enzyme action at functional groups Condensation Hydrolysis Fig. 3.5, p. 37

17. Animation: Condensation and hydrolysis CLICK HERE TO PLAY

18. Key Concepts:STRUCTURE DICTATES FUNCTION • We define cells partly by their capacity to build complex carbohydrates and lipids, proteins, and nucleic acids • The main building blocks are simple sugars, fatty acids, amino acids, and nucleotides • These organic compounds have a backbone of carbon atoms with functional groups attached

19. 3.2 Carbohydrates – The Most Abundant Ones • Three main types of carbohydrates • Monosaccharides (simple sugars) • Oligosaccharides (short chains) • Polysaccharides (complex carbohydrates) • Carbohydrate functions • Instant energy sources • Transportable or storable forms of energy • Structural materials

20. Simple Sugars: Glucose and Fructose

21. Oligosaccharides: Sucrose

22. glucose fructose sucrose c Formation of a sucrose molecule Fig. 3.6, p. 38

23. Complex Carbohydrates: Bonding Patterns

24. Complex Carbohydrates: Starch, Cellulose, and Glycogen

25. Complex Carbohydrates: Starch, Cellulose, and Glycogen

26. c Glycogen. In animals, this polysaccharide is a storage form for excess glucose. It is especially abundant in the liver and muscles of highly active animals, including fishes and people. Structure of cellulose Fig. 3.8, p. 39

27. Animation: Structure of starch and cellulose CLICK HERE TO PLAY

28. Complex Carbohydrates: Chitin

29. Key Concepts:CARBOHYDRATES • Carbohydrates are the most abundant biological molecules • Simple sugars function as transportable forms of energy or as quick energy sources • Complex carbohydrates are structural materials or energy reservoirs

30. 3.3 Greasy, Oily – Must Be Lipids • Lipids • Fats, phospholipids, waxes, and sterols • Don’t dissolve in water • Dissolve in nonpolar substances (other lipids) • Lipid functions • Major sources of energy • Structural materials • Used in cell membranes

31. Fats • Lipids with one, two, or three fatty acid tails • Saturated • Unsaturated (cis and trans) • Triglycerides (neutral fats ) • Three fatty acid tails • Most abundant animal fat (body fat) • Major energy reserves

32. Fatty Acids

33. Animation: Fatty acids CLICK HERE TO PLAY

34. Trans and Cis Fatty Acids

35. Triglyceride Formation

36. glycerol three fatty acid tails Triglyceride, a neutral fat Fig. 3.11, p. 40

37. Animation: Triglyceride formation CLICK HERE TO PLAY

38. Phospholipids • Main component of cell membranes • Hydrophilic head, hydrophobic tails

39. hydrophilic head two hydrophilic tails b Fig. 3.13, p. 41

40. c Cell membrane section Fig. 3.13, p. 41

41. Animation: Phospholipid structure CLICK HERE TO PLAY

42. Waxes • Firm, pliable, water repelling, lubricating

43. Sterols: Cholesterol • Membrane components; precursors of other molecules (steroid hormones)

44. Animation: Cholesterol CLICK HERE TO PLAY

45. Key Concepts:LIPIDS • Complex lipids function as energy reservoirs, structural materials of cell membranes, signaling molecules, and waterproofing or lubricating substances

46. 3.4 Proteins – Diversity in Structure and Function • Proteins have many functions • Structures • Nutrition • Enzymes • Transportation • Communication • Defense

47. Protein Structure • Built from 20 kinds of amino acids

48. Fig. 3.15, p. 42

49. amino group carboxyl group Fig. 3.15, p. 42

50. Fig. 3.15, p. 42