1. Chapter 5 The Structure and Function of Large Biological Molecules

2. You Must Know The role of dehydration synthesis in the formation of organic compounds and hydrolysis in the digestion of organic compounds. The role of dehydration synthesis in the formation of organic compounds and hydrolysis in the digestion of organic compounds. How to recognize the 4 biologically important organic compounds (carbs, lipids, proteins, nucleic acids) by their structural formulas. How to recognize the 4 biologically important organic compounds (carbs, lipids, proteins, nucleic acids) by their structural formulas. The cellular functions of all four organic compounds. The cellular functions of all four organic compounds. The 4 structural levels of proteins The 4 structural levels of proteins How proteins reach their final shape (conformation) and the denaturing impact that heat and pH can have on protein structure How proteins reach their final shape (conformation) and the denaturing impact that heat and pH can have on protein structure

3. MonomersPolymersMacromolecules Small organic Used for building blocks of polymers Connects with condensation reaction (dehydration synthesis) Long molecules of monomers With many identical or similar blocks linked by covalent bonds Giant molecules 2 or more polymers bonded together ie. amino acid  peptide  polypeptide  protein smaller larger

4. Dehydration Synthesis (Condensation Reaction) Hydrolysis Make polymersBreakdown polymers Monomers  PolymersPolymers  Monomers A + B  ABAB  A + B + H 2 O + +

6. I. Proteins “Proteios” = first or primary “Proteios” = first or primary 50% dry weight of cells 50% dry weight of cells Contains: C, H, O, N, S Contains: C, H, O, N, S Myoglobin protein

7. Protein Functions (+ examples) Enzymes (lactase) Enzymes (lactase) Defense (antibodies) Defense (antibodies) Storage (milk protein = casein) Storage (milk protein = casein) Transport (hemoglobin) Transport (hemoglobin) Hormones (insulin) Hormones (insulin) Receptors Receptors Movement (motor proteins) Movement (motor proteins) Structure (keratin) Structure (keratin)

8. Overview of protein functions

10. Four Levels of Protein Structure 1.Primary Amino acid (AA) sequence Amino acid (AA) sequence 20 different AA’s 20 different AA’s peptide bonds link AA’s peptide bonds link AA’s

11. Amino Acid R group = side chains R group = side chains Properties: Properties: hydrophobic hydrophobic hydrophilic hydrophilic ionic (acids & bases) ionic (acids & bases) “amino” : -NH 2 “amino” : -NH 2 “acid” : -COOH “acid” : -COOH

14. Four Levels of Protein Structure (continued) 2.Secondary Gains 3-D shape (folds, coils) by H-bonding Gains 3-D shape (folds, coils) by H-bonding Alpha (α) helix, Beta (β) pleated sheet Alpha (α) helix, Beta (β) pleated sheet

15. Basic Principles of Protein Folding A.Hydrophobic AA buried in interior of protein (hydrophobic interactions) B.Hydrophilic AA exposed on surface of protein (hydrogen bonds) C.Acidic + Basic AA form salt bridges (ionic bonds). D.Cysteines can form disulfide bonds.

16. Four Levels of Protein Structure (continued) 3.Tertiary Bonding between side chains (R groups) of amino acids Bonding between side chains (R groups) of amino acids H bonds, ionic bonds, disulfide bridges, van der Waals interactions H bonds, ionic bonds, disulfide bridges, van der Waals interactions

17. Four Levels of Protein Structure (continued) 4.Quaternary 2+ polypeptides bond together 2+ polypeptides bond together

18. amino acids  polypeptides  protein Bonding (ionic & H) can create asymmetrical attractions

19. Chaperonins assist in proper folding of proteins

20. Protein structure and function are sensitive to chemical and physical conditions Protein structure and function are sensitive to chemical and physical conditions Unfolds or denatures if pH and temperature are not optimal Unfolds or denatures if pH and temperature are not optimal

21. change in structure = change in function

22. Illustrative Examples: Variations within proteins provide a wider range of functions: Different types of hemoglobin Different types of hemoglobin MHC proteins MHC proteins

23. II. Nucleic Acids Function: store hereditary info DNARNA Double-stranded helix Thymine N-bases: A, G, C, Thymine Stores hereditary info Longer/larger Sugar: deoxyribose Single-stranded Uracil N-bases: A, G, C, Uracil Carry info from DNA to ribosomes tRNA, rRNA, mRNA, RNAi Sugar: ribose

24. Nucleotides: monomer of DNA/RNA Nucleotide = Sugar + Phosphate + Nitrogen Base

25. Nucleotide phosphate 5-C sugar Nitrogen base A – T G – C PurinesPyrimidines Adenine Guanine Cytosine Thymine (DNA) Uracil (RNA) Double ring Single ring

27. Information flow in a cell: DNA  RNA  protein

28. III. Carbohydrates Fuel and building material Fuel and building material Include simple sugars (fructose) and polymers (starch) Include simple sugars (fructose) and polymers (starch) Ratio of 1 carbon: 2 hydrogen: 1 oxygen or CH 2 O Ratio of 1 carbon: 2 hydrogen: 1 oxygen or CH 2 O monosaccharide  disaccharide  polysaccharide monosaccharide  disaccharide  polysaccharide Monosaccharides = monomers (eg. glucose, ribose) Monosaccharides = monomers (eg. glucose, ribose) Polysaccharides: Polysaccharides:  Storage (plants-starch, animals-glycogen)  Structure (plant-cellulose, arthropod-chitin ) Differ in position & orientation of glycosidic linkage

29. The structure and classification of some monosaccharides

30. Linear and ring forms of glucose

31. Carbohydrate synthesis

32. Cellulose vs. Starch Two Forms of Glucose:  glucose &  glucose

33. Cellulose vs. Starch Starch =  glucose monomers Starch =  glucose monomers Cellulose =  glucose monomers Cellulose =  glucose monomers

34. Storage polysaccharides of plants (starch) and animals (glycogen)

35. Structural polysaccharides: cellulose & chitin (exoskeleton)

36. II. Lipids A.Fats (triglyceride): A.Fats (triglyceride): store energy Glycerol + 3 Fatty Acids saturated, unsaturated, polyunsaturated B.Steroids B.Steroids: cholesterol and hormones C.Phospholipids: lipid bilayer of C.Phospholipids: lipid bilayer of cell membrane hydrophilic head, hydrophobic tails Hydrophilic head Hydrophobic tail

38. SaturatedUnsaturatedPolyunsaturated “saturated” with HHave some C=C, result in kinks In animalsIn plants Solid at room temp.Liquid at room temp. Eg. butter, lardEg. corn oil, olive oil

39. Cholesterol, a steroid

40. The structure of a phospholipid

41. Hydrophobic/hydrophilic interactions make a phospholipid bilayer

42. Illustrative Example Different types of phospholipids Different types of phospholipids