Lecture 3: Biological Macromolecules



Living Organisms Are not in Equilibrium With Their Surroundings


AdenosineTriphosphate (ATP) is the Energy Currency of the Cell

Cells Contain 4 Major Types of Giant Molecules (Macromolecules or Polymers)

Biological Polymers are Made From About 60 Small Building Blocks

 Building Blocks  Number of Kinds  Polymers
 Amino Acids  20  Proteins
 Fatty Acids  10  Storage Lipids/Membranes
 Sugars & Relatives 10  Polysaccharides/Nucleic Acids
 Nucleotides  5  Nucleic Acids
 Others 15  All of Above

Proteins are Made up of Exactly 20 Types of Amino Acids


Proteins Do Most of the Work of the Cell

Nucleic Acids are the Molecules of Heredity

Lipids Form Cell Membranes and Energy Storage Depots

Polysaccharides are Used for Structure and Energy Storage

Summary of Biological Macromolecules
 Macromolecule  Building Blocks  Functions
 Polysaccharides Sugars Energy storage (4 Cal/gm)
Structure (cell walls, exoskeletons)
 Lipids: triglycerides Fatty acids, glycerol Energy storage (9 Cal/gm)
 Lipids: phospholipids Fatty acids, glycerol, phosphate, polar groups Cell membranes
 Proteins Amino acids: 20 types Cell structure
Molecular motors (muscle, etc)
Membrane pumps & channels
Hormones & receptors
Immune system: antibodies
 Nucleic Acids: DNA
(forms a double helix)
4 Bases: A, C, G, T
Deoxyribose sugar, phosphate
Storage of hereditary information (genetic code)

Nucleic Acids: RNA
3 types:

  • m-RNA
  • t-RNA
  • r-RNA

(usually a single strand)

4 Bases: A, C, G, U
Ribose sugar,

Protein synthesis:

  • m-RNA: working copy of genetic code for a gene (transcription)
  • t-RNA & r-RNA: translation of the code