1. Chapter 5 The Structure and Function of Large 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
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 Fats Unsaturated 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.

51. Amino Acids All have a Carbon with four attachments: -COOH (acid)
-NH2 (amine) -H
-R (some other side group)

52. R groups 20 different kinds: Nonpolar - 9 AA Polar - 6 AA
Electrically Charged
Acidic - 2 AA
Basic - 3 AA

53. Amino Acids

54. Amino Acids

55. R groups Contain the S when present in a protein.
Cysteine or Cys
Methionine or Met
The properties of the R groups determine the properties of the protein.

56. Polypeptide Chains
Formed by dehydration synthesis between the carboxyl group of one AA and the amino group of the second AA.
Produce an backbone of: (N-C-C)X

58. Levels Of Protein Structure
Organizing the polypeptide into its 3-D functional shape.
Primary
Secondary
Tertiary
Quaternary

59. Primary Sequence of amino acids in the polypeptide chain.
Many different sequences are possible with AAs.

61. Secondary
3-D structure formed by hydrogen bonding between parts of the peptide backbone.
Two main secondary structures:
a helix
pleated sheets

62. Tertiary Bonding between the R groups. Examples:
hydrophobic interactions
ionic bonding
Disulfide bridges (covalent bond)

63. Quaternary
When two or more polypeptides unite to form a functional protein.
Example: hemoglobin

64. Is Protein Structure Important?

66. Denaturing Of A Protein
Events that cause a protein to lose structure (and function).
Example:
pH shifts
high salt concentrations
heat

68. Chaperone Proteins
Large protein complexes that help fold other proteins into their correct shape.
Often used when cells are stressed to keep proteins intact and functioning.

70. Comment Many other amino acids are possible (change the R group)
Whole new group of proteins with new properties can be made
Genetic engineering can use bacteria to make these new proteins

71. Nucleic Acids Informational polymers Made of C,H,O,N and P
No general formula
Examples: DNA and RNA

72. Nucleic Acids Polymers of nucleotides Nucleotides have three parts:
nitrogenous base
pentose sugar
phosphate

73. Nitrogenous Bases Rings of C and N
The N atoms tend to take up H+ (base).
Two types:
Pyrimidines (single ring)
Purines (double rings)

74. Pentose Sugar 5-C sugar Ribose - RNA Deoxyribose – DNA
RNA and DNA differ in a –OH group on the 2nd carbon.

75. Nucleosides and Nucleotides
Nucleoside = base + sugar
Nucleotide = base + sugar + Pi

77. DNA Deoxyribonucleic Acid. Makes up genes.
Genetic information for life.

78. RNA Ribonucleic Acid. Structure and protein synthesis.
Genetic information for a few viruses only.

79. DNA and RNA
More will be said about DNA and RNA in future lessons.

80. Summary Role of hydrolysis and dehydration synthesis
For each macromolecule, know the following:
Elements and monomers
Structures
Functions