Biomolecules: The Stuff of Life

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Biomolecules The Stuff of Life
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Several classes of molecules comprise the cell,
which make up the complete organism

• Proteins
• Polymers of amino acids
• 20 are naturally occurring
• 19/20 are CHIRAL

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Example
L-Dopa Anti-Parkinsons disease drug
D-Dopa Biologically inactive
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Several classes of molecules comprise the cell,
which make up the complete organism

• Proteins
• Polymers of amino acids
• 20 are naturally occurring
• 19/20 are CHIRAL
• Connected by peptide (amide) bonds
• Primary structure folds into complex 3-D shapes
  to form functional protein
• Shapes include alpha helix (corkscrew) and beta
  sheet

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Proteins are classified by function
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Enzymes

• Biological catalysts
• CATALYST a substance that increases the RATE of
  a chemical reaction
• Highly SPECIFIC for substrate
• Induced Fit model Substrate fits into cavity
  in enzyme
• Many drugs act by mimicking the natural
  substrate
• E.g., statins for lowering cholesterol

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The Implications of Stereochemistry on DrugsThe
Thalidomide Problem
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Nucleic Acids

• Sugar phosphate group BASE nucleotide
• Polymer of nucleotides nucleic acid
• RNA (ribonucleic acid)
• vs. DNA (deoxyribonucleic acid)

The Central Dogma DNA ? RNA ? Protein
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The Double Helix

• Structure was solved by Francis Crick, James
  Watson, Rosalind Franklin, and Maurice Wilkins in
  1953 at Cambridge and Rockefeller Universities
• Erwin Chargaff discovered base pairing (A-T and
  G-C)
• Entire human genome was sequenced in 2003 through
  government-private investigations

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Lipids

• Like dissolves like oil and water do not mix
• Lipids are molecules which do not dissolve in
  water
• Most have water-fearing and water-loving
  regions in the same molecule
• In water, they form
• BILAYERS
• MICELLES
• These bilayers are semi-permeable
• They allow some molecules to pass
• Cystic Fibrosis
• Defect in gene coding for channel protein

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Types of Lipids

• Fatty acids
• Saturated
• Unsaturated
• Triglycerides
• Sterols
• Cholesterol
• Testosterone
• Estradiol
• Phospholipids
• Lecithin
• Sphingolipids
• Cerebrosides

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Saturated vs. Unsaturated
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Sugars (Saccharides Carbohydrates)

• The metabolic breakdown of GLUCOSE is the source
  of energy for the cell
• This sugar undergoes a series of chemical
  reactions, culminating with the acceptance of
  electrons by OXYGEN to produce WATER
• The other product is CARBON DIOXIDE