Chapter 5 The Structure and Function of Macromolecules

1
Chapter 5 The Structure and Function of
Macromolecules
2
Focus on

• Elements in each molecule
• How 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.

7
(No Transcript)
8
Four Main Types Of Macromolecules

• Carbohydrates
• Lipids
• Proteins
• 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
• CO ratio is 11

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.

14
(No Transcript)
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.

18
(No Transcript)
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

22
(No Transcript)
23
a glucose and b glucose
24
(No Transcript)
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
29
(No Transcript)
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.
• CO ratio is very high in C.

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 CC bonds. Can accept
  more Hydrogens.
• Double bonds cause kinks in the molecules
  shape.

40
(No Transcript)
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.

45
(No Transcript)
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 a backbone of (N-C-C)X

57
(No Transcript)
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 20
  AAs.

60
(No Transcript)
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?
65
Denaturing Of A Protein

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

66
(No Transcript)
67
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

68
Nucleic Acids

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

69
Nucleic Acids

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

70
Nitrogenous Bases

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

71
Pentose Sugar

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

72
Nucleosides and Nucleotides

• Nucleoside base sugar
• Nucleotide base sugar Pi

73
(No Transcript)
74
DNA

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

75
RNA

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

76
DNA and RNA

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

77
Summary

• Role of hydrolysis and dehydration synthesis
• For each macromolecule, know the following
• Elements and monomers
• Structures
• Functions