Chapter 5: The Structure and Function of Macromolecules

1
Chapter 5 The Structure and Function
of Macromolecules
2
Macromolecules

• Large molecules formed by joining many subunits
  together.
• Also known as polymers.

3
Monomer

• A building block of a polymer.

AP Biology
4
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.

5
Hydrolysis

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

6
(No Transcript)
7
4 Main Types Of Macromolecules

• Carbohydrates
• Lipids
• Protein
• Nucleic acids

8
Carbohydrates

• Used for fuel, building materials, and receptors.
• Made of C,H,O
• General formula is CH2O
• CO ratio is 11

9
Types Of Carbohydrates

• Monosaccharides
• Disaccharides
• Oligosaccharides
• Polysaccharides

10
Monosaccharides

• Mono - single
• Saccharide - sugar
• Simple sugars.
• 3 to 7 carbons.
• Can be in linear or ring forms.
• Can be Aldoses or Ketoses depending on the
  location of the carbonyl group.

11
(No Transcript)
12
Examples

• Glucose
• Galactose
• Ribose
• Fructose

13
- OSE

• Word ending common for many carbohydrates.

14
Disaccharides

• Sugar formed by joining two monosaccharides
  through a glycosidic linkage.

15
(No Transcript)
16
Examples

• Maltose glucose glucose
• Lactose glucose galactose
• Sucrose glucose fructose

17
Oligosaccharides

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

18
Polysaccharides

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

19
(No Transcript)
20
a glucose and b glucose
21
(No Transcript)
22
Starch

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

23
a glucose
24
Cellulose

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

25
b glucose
26
(No Transcript)
27
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.

28
Glycogen

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

29
Starch
Glycogen
30
Lipids

• Diverse hydrophobic molecules.
• Made of C,H,O
• No general formula.
• CO ratio is very high in C.

31
Fats and Oils

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

32
Fats and Oils

• Made of two kinds of smaller molecules.
• Fatty Acids
• Glycerol

33
Fatty Acids

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

34
Acid
Fat
35
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.

36
Saturated Fats/Unsaturated Fats

• Saturated - no double bonds.
• Unsaturated - one or more CC bonds. Can accept
  more Hydrogens.
• Double bonds cause kinks in the molecules
  shape.

37
(No Transcript)
38
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.

39
Fats

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

40
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.

41
Phospholipids

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

42
(No Transcript)
43
Result

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

44
Steroids

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

45
Proteins

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

46
Uses Of Proteins
Movie

• Structure
• Enzymes
• Antibodies
• Transport
• Movement
• Receptors
• Hormones

47
Proteins

• Polypeptide chains of Amino Acids linked by
  peptide bonds.

48
Amino Acids

• All have a Carbon with four attachments
• -COOH (acid)
• -NH2 (amine)
• -H
• -R (some other side group)

49
R groups

• 20 different kinds
• Nonpolar - 9 AA
• Polar - 6 AA
• Electrically Charged
• Acidic - 2 AA
• Basic - 3 AA

50
Amino Acids
51
Amino Acids
52
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.

53
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

54
(No Transcript)
55
Levels Of Protein Structure

• Organizing the polypeptide into its 3-D
  functional shape.
• Primary
• Secondary
• Tertiary
• Quaternary

56
Primary

• Sequence of amino acids in the
  polypeptide chain.
• Many different sequences are
• possible with 20 AAs.

57
Secondary

• 3-D structure formed by hydrogen bonding between
  the R groups.
• Two main secondary structures
• a helix
• pleated sheets

58
Tertiary

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

59
Quaternary

• When two or more polypeptides unite to form a
  functional protein.
• Example hemoglobin

60
Is Protein Structure Important?
61
Denaturing Of A Protein

• Events that cause a protein to lose structure
  (and function).
• Example
• pH shifts
• high salt concentrations
• heat

62
(No Transcript)
63
Nucleic Acids

• Informational polymers
• Made of C,H,O,N and P
• No general formula
• Examples DNA and RNA

64
Nucleic Acids

• Polymers of nucleotides
• Nucleotides have three parts
• nitrogenous base
• pentose sugar
• phosphate

65
Nitrogenous Bases

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

66
Pentose Sugar

• 5-C sugar
• Ribose - RNA
• Deoxyribose DNA
• RNA and DNA differ in a OH group on the 3rd
  carbon.

67
Nucleosides and Nucleotides

• Nucleoside base sugar
• Nucleotide base sugar Pi

68
(No Transcript)
69
DNA

• Deoxyribonucleic Acid.
• Makes up genes.
• Genetic information source for most life.

70
RNA

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

71
Summary

• For each macromolecule, know the following
• Elements and monomers
• Structures
• Functions