1. Biological Molecules

2. Mad Cow Clues In The News

3. General Characteristics of Biological Molecules Carbon based Interact by means of functional groups Assembled or disassembled by adding or removing water

4. Carbon and Biological Molecules Able to form 4 stable bonds Organic Compounds – contain carbon Few inorganic compounds contain carbon C

5. Functional Groups Group with distinct chemical properties Carbon is skeleton holding groups of atoms Chemical reactions within organisms involve transfer of a functional group Macromolecules –many functional groups

9. Changing Molecules Assembling molecules –Growth and repair –Producing molecules essential for chemical reactions to take place Disassembling molecules –Digestion –Providing molecules that can enter cells

10. Assembly: Dehydration Synthesis Monomers = building blocks Monomers are linked with covalent bonds Polymers = chain-like molecules

11. Dehydration Synthesis One molecule of water is removed Two monomers are joined –One loses hydroxyl group –Other loses hydrogen

12. Disassembly: Hydrolysis Hydrolysis is opposite of dehydration Covalent bonds broken with addition of H 2 O Energy in bond is released

13. Major Classes of Biological Molecules

14. Carbohydrates Contain C,H, & O H:O = 2:1 Primary role is for energy Breaking bonds releases energy Glucose

15. Carbohydrate Example: Glucose

16. Monosaccharides Simplest carbohydrates Individual sugar molecules

17. Disaccharide Monosaccharides linked together Less readily broken during transport

18. Polysaccharides Long polymers of sugars Insoluble Called complex carbohydrates

19. Common Polysaccharides Starches –Stored energy in plants Glycogen –Animal energy storage

20. Some Carbohydrates are Used for Structure Cellulose – plant cell wall material Chitin – in insects, fungi

21. Lipids H:O ratio higher than 2:1 Not dissolved in water Categories of lipids –Oils, fats & waxes –Phospholipids –steroids

22. Fats Non-polar & insoluble Work well for storage More energy than equivalent carbohydrates Two types of subunits –Glycerol –Fatty acids

23. Triglyceride Molecule with 3 fatty acids Includes most dietary fat

24. Triglycerides Saturated – carries as many H as possible

25. Triglycerides Unsaturated – double bond replaces H Polyunsaturated – more than 1 double bond

26. Differences in Fats & Oils Polyunsaturated –Plant oils –Fish oils Saturated –Animal fats There are exceptions

28. Waxes Chemical backbone differs from fats & oils One carbon chain Water resistant

29. Phospholipids Phosphate group replaces a fatty acid Key component of cell membrane

30. Steroids With 4 carbon rings Important for membranes

31. Proteins Transport other molecules Provide for muscle contraction Help protect body Play role in nerve transmission Control growth Serve as enzymes Act as chemical messenger

32. Protein Structure Chain of amino acids Polypeptide bond

33. Protein Synthesis & Hydrolysis

34. Protein Levels of Structure Primary structure = amino acid sequence Secondary structure = shape –Coils –Folds Tertiary structure = complex shape caused by hydrogen bonds

36. Protein Function Dependent upon 3-dimensional structure Can be degraded by heat

37. Nucleic Acids Composed of nucleotides Stores information

38. Forms of Nucleic Acid DNA = deoxyribonucleic acid RNA = ribonucleic acid

39. End Chapter 4