Carbon and the Molecular Diversity of Life

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Carbon and the Molecular Diversity of Life

• Chapter 4
• Biology Campbell Reece

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Importance of Carbon

• Organic chemistry the study of carbon compounds
• Most versatile building blocks of molecules
• It has 4 valence electrons
• Shares them in covalent bonds (not likely to form
  ionic)
• It makes large complex molecules possible.
• It determines an organic molecules three
  dimensional shape

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Importance of Carbon

• Variation in carbon skeletons contributes to the
  diversity of organic molecules
• Length
• Shape (straight, branched, ring)
• Number and location of double bonds
• Other elements covalently bonded to available
  sites

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Hydrocarbons

• Contain only carbon and hydrogen
• Have a diversity of carbon skeletons which
  produce molecules of various lengths and shapes
• Are hydrophobic because the C-C and C-H bonds are
  nonpolar
• Biologically important molecules (fats)

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Structure of hydrocarbons
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Isomers

• Compounds with the same molecular formula but
  with different structures and different
  properties
• Structural isomers differ in the covalent
  arrangement of their atoms (and location of
  double bonds)
• Geometric isomers share the same covalent
  partnerships, but differ in spatial arrangements.
• cis isomer on the same side of the double bond
• trans isomer on opposite sides

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Isomers

• Enantiomers isomers that are mirror images of
  each other
• Can occur when four different atoms or groups of
  atoms are bonded to the same carbon.
• Two different spatial arrangements
• Usually, one form is biologically active and the
  other is not

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Isomers
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Functional Groups

• Contribute to the molecular diversity of life
• Have specific chemical and physical properties
• Are chemically active regions of organic
  molecules
• Behave consistently from one organic molecule to
  another
• Determine unique chemical properties of the
  molecules in which they occur

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Hydroxyl Group
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Carbonyl Group
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Carboxyl Group
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Amino Group
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Sulfhydryl Group
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Phosphate Group
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Methyl Group