Chapter 5 The Structure and Function of Large Biological Molecules

1. Chapter 5 The Structure and Function ofLarge Biological Molecules

2. Focus on: • Elements in each large biological molecule • How these molecules are linked and unlinked • Examples and functions of each type of molecule

3. Macromolecules • Large molecules formed by joining many subunits together. • Also known as “polymers”.

4. Monomer • A building block of a polymer. AP Biology

5. Condensation Synthesis or Dehydration Synthesis • The chemical reaction that joins monomers into polymers. • Covalent bonds are formed by the removal of a water molecule between the monomers.

6. Hydrolysis • Reverse of condensation synthesis. • Hydro- water • Lysis - to split • Breaks polymers into monomers by adding water.

8. Four Main Types Of Macromolecules or Large Biological Molecules • Carbohydrates • Lipids • Protein • Nucleic acids

9. For each Macromolecule know the following: • Elements it contains • Monomer units and structures • Examples • Uses or roles

10. Carbohydrates • Used for fuel, building materials, and receptors. • Made of C,H,O • General formula is CH2O • C:O ratio is 1:1

11. Types Of Carbohydrates • Monosaccharides • Disaccharides • Oligosaccharides • Polysaccharides

12. Monosaccharides • Mono - single • Saccharide - sugar • Simple sugars. • 3 to 7 carbons. • Can be in linear or ring forms.

13. Monosaccharides • Can be “Aldoses” or “Ketoses” depending on the location of the carbonyl group.

15. Examples • Glucose • Galactose • Ribose • Fructose

16. - OSE • Word ending common for many carbohydrates.

17. Disaccharides • Sugar formed by joining two monosaccharides through a “glycosidic linkage”.

19. Examples • Maltose = glucose + glucose • Lactose = glucose + galactose • Sucrose = glucose + fructose

20. Oligosaccharides • 2 - 10 joined simple sugars. • Used in cell membranes.

21. Polysaccharides • Many joined simple sugars. • Used for storage or structure. • Examples: • Starch • Cellulose • Glycogen

23. a glucose and b glucose

25. Starch • Made of 1-4 linkages of a glucose. • Linkage makes the molecule form a helix. • Fuel storage in plants.

26. a glucose

27. Cellulose • Made of 1-4 linkages of b glucose. • Linkage makes the molecule form a straight line. • Used for structure in plant cell walls.

28. b glucose

30. Comment • Most organisms can digest starch (1- 4 a linkage), but very few can digest cellulose (1- 4 b linkage). • Another example of the link between structure and function.

31. Glycogen • “Animal starch” • Similar to starch, but has more 1-6 linkages or branches. • Found in the liver and muscle cells.

32. Starch Glycogen

33. Lipids • Diverse hydrophobic molecules • Made of C,H,O • No general formula • C:O ratio is very high in C • Not strictly speaking a macromolecule like the others

34. Fats and Oils • Fats - solid at room temperature. • Oils - liquid at room temperature.

35. Fats and Oils • Made of two kinds of smaller molecules. • Fatty Acids • Glycerol

36. Fatty Acids • A long carbon chain (12-18 C) with a -COOH (acid) on one end and a -CH3 (fat) at the other.

37. Acid Fat

38. Neutral Fats or Triacylglycerols • Three fatty acids joined to one glycerol. • Joined by an “ester” linkage between the -COOH of the fatty acid and the -OH of the alcohol.

39. Saturated FatsUnsaturated Fats • Saturated - no double bonds. • Unsaturated - one or more C=C bonds. Can accept more Hydrogens. • Double bonds cause “kinks” in the molecule’s shape.

41. Question • Why do fats usually contain saturated fatty acids and oils usually contain unsaturated fatty acids? • The double bond pushes the molecules apart, lowering the density, which lowers the melting point.

42. Fats • Differ in which fatty acids are used. • Used for energy storage, cushions for organs, insulation.

43. Question ? • Which has more energy, a kg of fat or a kg of starch? • Fat - there are more C-H bonds which provide more energy per mass.

44. Phospholipids • Similar to fats, but have only two fatty acids. • The third -OH of glycerol is joined to a phosphate containing molecule.

46. Result • Phospholipids have a hydrophobic tail, but a hydrophilic head. • Self-assembles into micells or bilayers, an important part of cell membranes.

47. Steroids • Lipids with four fused rings. • Differ in the functional groups attached to the rings. • Examples: • cholesterol • sex hormones

48. Proteins • The molecular tools of the cell. • Made of C,H,O,N, and sometimes S. • No general formula.

49. Uses Of Proteins • Structure • Enzymes • Antibodies • Transport • Movement • Receptors • Hormones

50. Proteins • Polypeptide chains of Amino Acids linked by peptide bonds.