2. Biological Molecules and … Digestion

3. Carbohydrates All contain the elements carbon hydrogen oxygen Twice as many hydrogen atoms as oxygen atoms in each molecule

4. Three main types Monosaccharide Disaccharide Polysaccharide

5. Monosaccharides Are the simple sugars e.g. glucose, fructose, galactose These are the monomers

6. Glucose  -glucose

9. Disaccharides Contain two simple sugars joined together Glycosidic bond is formed e.g. maltose, sucrose, lactose

10. Disaccharides Monomers join by a condensation reaction Water is given out

12. Condensation

13. Glycosidic bond

15. Maltose Two molecules of  -glucose joined together

16. Sucrose One molecule of  -glucose joined to one molecule of fructose

18. Polysaccharides Contains many simple sugars e.g. starch

19. Polysaccharide

20. Starch – for storage Compact  lots of glucose can be stored in a small space Easily broken down  supply glucose when needed for respiration

21. Lipids One of the most important types is: triglycerides Usually known as: fats and oils

22. Fat - Solid at room temperature

23. Oil - Liquid at room temperature

24. Triglycerides Consists of :- three fatty acid molecules one glycerol

32. Saturated and unsaturated triglycerides Depends on the form of the fatty acid chains

35. Proteins Polymer Monomer is amino acid Draw an amino acid

36. Amino group Carboxylic group

37. Amino acids 20 different amino acids Joined together by condensation Peptide bond is formed

38. Polypeptide is many amino acids joined together

43. Polypeptide – primary structure Chain of amino acids Held together by peptide bonds Differences due to the type, number and position of amino acid

44. Secondary structure Folding of polypeptide chain forming an alpha helix

45. Secondary structure Held together by hydrogen bonds

46. Tertiary structure Further folding of secondary structure, held together by hydrogen, ionic, disulphide and hydrophobic bonds

47. Quaternary structure More than one polypeptide joined together

49. The digestive system

50. Heterotrophic Nutrition Organisms that can not manufacture the organic molecules they require Must eat them Must consume them – CONSUMERS OR HETEROTROPHS Most of the chemicals eaten are storage molecules

51. Digestion Definition : Break down of large insoluble organic molecules into small soluble organic molecules

53. Classes of organic molecules StarchLipidProtein

54. How are the molecules joined together? StarchLipidProtein

55. How are the molecules joined together? StarchLipidProtein Glycosidic bond Ester bond Peptide bond

56. What enzymes break them down? StarchLipidProtein

57. What enzymes break them down? StarchLipidProtein CarbohydraseLipaseProtease

58. What type of reaction is involved? StarchLipidProtein

59. What type of reaction is involved? StarchLipidProtein Hydrolysis

60. The addition of water to break down a large molecule into a smaller molecule

61. Condensation Removal of water to join two molecules together

62. Breakdown of starch Starch amylase salivary gland pancreas Maltose maltase ileum Glucose

63. Membrane attached enzymes Most enzymes are secreted into the gut BUT Some enzymes are attached to membrane of the epithelial cells of the ileum

64. Examples of...... membrane attached enzymes Maltase Sucrase Lactase

65. Why are the enzymes attached to the membranes? The reactions they control, produce molecules which can be absorbed through the membrane If this happened in the centre of the gut the molecules may never come in contact with the membrane

66. What is the difference between maltose, sucrose and lactose? Glucose plus glucose - maltose Glucose plus fructose - sucrose Glucose plus galactose - lactose

67. Absorption Passing the products of digestion into the cells lining the gut

68. Assimilation Making the absorbed molecules part of the cells of the body