Exploring Macromolecules: Carbohydrates, Lipids, Proteins, Nucleic Acids

1. Chapter 5 Macromolecules

2. Macromolecules • Smaller organic molecules join together to form larger molecules called macromolecules • 4 major classes of macromolecules: • carbohydrates • lipids • proteins • nucleic acids

3. Polymers • Long molecules built by linking chain of repeating smaller units • polymers • monomers = repeated small units • covalent bonds

4. How to build a polymer • Condensation reactions are used to build polymers • dehydration synthesis • joins monomers by “taking” H2O out • requires energy & enzymes

5. How to break down a polymer • Hydrolysis breaks apart polymers • use H2O to break apart monomers • reverse of condensation reaction • H2O is split into H and OH • This releases energy

6. CARBOHYDRATES

7. Carbohydrates • Carbohydrates are composed of C, H, O Function: • energy u energy storage • raw materials u structural materials • Monomer: monosaccharides • Polymers: polysaccharides • ex: sugars & starches (bread, pasta, rice, potatoes, fruit, vegetables)

8. Simple & complex sugars • Monosaccharides • simple 1 monomer sugars • Glucose and fructose • Disaccharides • 2 monomers • Sucrose and maltose • Polysaccharides • large polymers (4)

9. Polysaccharides • Function: • energy storage • starch (plants) • glycogen (animals) • building materials = structure • cellulose (plants) • chitin (arthropods & fungi)

10. LIPIDS

11. Lipids • Lipids are composed of C, H, O • long hydrocarbon chain • Diverse group • fats • phospholipids • Steroids • Monomers= glycerol and 3 fatty acids • Polymer=triglycerides (fat)

12. Fat • Triglycerol • 3 fatty acids linked to glycerol

13. Fats • Long HC chain • non-polar • hydrophobic • Function: • energy storage • cushion organs • insulates body • Healthy brains

14. Saturated fats • Saturated fats have all C bonded to H singly • No C=C double bonds • long, straight chain • most animal fats • solid at room temp. • Less healthy: butter, lard, crisco

15. Unsaturated fats • Unsaturated fats have C=C double bonds in the fatty acids • Not saturated by hydrogens • Crooked chains • plant & fish fats • vegetable oils (olive, sesame, peanut) • liquid at room temperature • healthier

16. Phospholipids • Structure: • glycerol + 2 fatty acids + PO4

17. Phospholipids & cells • Phospholipids of cell membrane • double layer = bilayer • hydrophilic heads on outside • hydrophobic tails on inside • forms barrier between cell & external environment

18. Steroids • ex: cholesterol, sex hormones cholesterol

19. PROTEINS

20. Proteins • Proteins are the most structurally & functionally diverse group of biomolecules • Function: • involved in almost everything • Movement, growth • Enzymes • antibodies • structure (keratin, collagen) • carriers & transport (membrane channels) • receptors & binding (defense) • contraction (actin & myosin) • signalling (hormones) • storage (bean seed proteins)

21. Proteins • Structure: • monomer = amino acids • 20 different amino acids • polymer = polypeptide • complex 3-D shape

22. Structure: • central carbon • amino group • carboxyl group (acid) • R group (side chain) • variable group • confers unique chemical properties of the amino acid H | —C— | O H C—OH || H R Amino acids

23. hemoglobin collagen Protein structure & function • function depends on structure • 3-D structure • twisted, folded, coiled into unique shape pepsin

24. Primary (1°) structure • Order of amino acids in chain • A long ribbon

25. Secondary (2°) structure • “Local folding” • Hydrogen bonds between R groups • -helix (spiral) • -pleated sheet (pleats)

26. Tertiary (3°) structure • “Whole molecule folding” • Hydrogen bonds

27. Quaternary (4°) structure • Joins together more than 1 polypeptide chain • only then is it a functional protein collagen = skin & tendons hemoglobin

28. Denature a protein • Disrupt 3° structure • pH salt • temperature • unravel or denature protein • “change the shape, change the function” • Some proteins can return to their functional shape after denaturation, many cannot

29. Nucleic Acids

30. Nucleic Acids • Function: • store & transmit hereditary information • Polymers/Examples: • RNA (ribonucleic acid) • DNA (deoxyribonucleic acid) • Structure: • monomers = nucleotides

31. Nucleotides • 3 parts • nitrogen base (C-N ring) • pentose sugar (5C) • ribose in RNA • deoxyribose in DNA • PO4 group (phosphate)

32. Types of nucleotides • 2 types of nucleotides • different Nitrogen bases • purines • double ring N base • adenine (A) • guanine (G) • pyrimidines • single ring N base • cytosine (C) • thymine (T) • uracil (U)

33. RNA & DNA • RNA (makes protein) • single nucleotide chain • Ribose sugar • A, U, C, G • DNA (genetic code) • double nucleotide chain • Deoxyribose sugar • A, T, C, G

34. Macromolecule Summary • Carbohydrates • Monomers=monosaccharides • Polymers=polysaccharides • Used for energy, ex. Sugar • Lipids=fats=triglycerides • Monomers=glycerol + 3 fatty acids • Polymers=triglycerides • Used for energy, ex. Steroids, cell membranes

35. Macromolecule Summary • Nucleic Acids • Monomers=nucleotides • Polymers=nucleic acids • Store genetic information, ex. DNA, RNA • Proteins • Monomers=amino acids • Polymers=polypeptides • Used for growth, transport, communication, ex. hair, nails, enzymes, meat, nuts, beans, dairy