Ch04+Carbon+-+4

Carbon: The Backbone of Life

  • Living organisms consist mostly of carbon-based compounds.
  • Carbon is unparalleled in its ability to form large, complex, and varied molecules, making it essential for life.
  • Major organic molecules that define living matter, such as proteins, DNA, carbohydrates, are all composed of carbon compounds.

Versatile Carbon

  • Carbon is present in all life forms, showcasing its universality.

Carbon's Bonding Capability

  • Carbon has the ability to form four bonds, which creates a variety of molecular structures.

Elements of Life

  • The overall percentages of major elements essential for life include:
    • Carbon (C)
    • Hydrogen (H)
    • Oxygen (O)
    • Nitrogen (N)
    • Sulfur (S)
    • Phosphorus (P)
  • These elements are uniform across different organisms.
  • The ability of carbon to form four bonds allows for the construction of an inexhaustible variety of organic molecules, contributing to biodiversity on Earth.

Molecular Representations of Carbon Compounds

  • Methane (CH₄)
    • Molecular Formula: CH₄
    • Structural Formula: Displays the connection between carbon and hydrogen.
    • Ball-and-Stick Model: 3D visualization of atoms and bonds.
    • Space-Filling Model: Represents the volume of the molecule.
  • Ethane (C₂H₆)
  • Ethene (C₂H₄)

Valence Electrons and Covalent Bonds

  • The number of unpaired electrons in the valence shell corresponds with an atom's valence, which indicates the number of covalent bonds it can form.
  • Examples of valences:
    • Hydrogen (valence = 1)
    • Oxygen (valence = 2)
    • Nitrogen (valence = 3)
    • Carbon (valence = 4)

Electron Configuration of Carbon

  • Carbon's electron configuration allows for covalent compatibility with many elements.
  • The valences of carbon and its frequent partners (H, O, N) serve as the foundational building code for the architecture of living molecules.

Carbon and Other Atoms

  • Carbon can bond with other atoms beyond hydrogen.
  • Example: Carbon Dioxide (CO₂)

Molecular Diversity from Carbon Skeletons

  • Carbon chains form the backbone or skeletons of most organic molecules.

  • Carbon chains can vary in:

    • Length

    • Shape

    • Variations include:

    • (a) Chain Length

      • Ethane
      • Propane
      • Butane

    • (b) Branching

      • 2-Methylpropane (Isobutane)

    • (c) Double bond positions

      • 1-Butene
      • 2-Butene

    • (d) Ring structures

      • Cyclohexane
      • Benzene

Hydrocarbons

  • Hydrocarbons are organic molecules made solely of carbon and hydrogen.
  • Commonly found in organic molecules like fats.
  • Hydrocarbons can undergo reactions that yield a large amount of energy.

Isomers

  • Isomers are compounds with the same molecular formula but different structures and properties.

  • Types of isomers include:

    • Structural Isomers: Different covalent arrangements of atoms.
    • Cis-Trans Isomers: Same covalent bonds with differing spatial arrangements.
    • Enantiomers: Isomers that are mirror images of each other.

  • Examples:

    • (a) Structural isomers: Pentane vs 2-Methylbutane.
    • (b) Cis-trans isomers:
    • Cis isomer: The two Xs are on the same side.
    • Trans isomer: The two Xs are on opposite sides.
    • (c) Enantiomers: L isomer vs D isomer.

Importance of Enantiomers

  • Enantiomers hold significance in the pharmaceutical industry as they may produce different biological effects.
  • Only one enantiomer is usually biologically active.
  • Example effects:
    • Ibuprofen:
    • S-Ibuprofen: Reduces inflammation and pain.
    • R-Ibuprofen: Relaxes bronchial muscles (asthma treatment).
    • Albuterol:
    • R-Albuterol (effective) vs S-Albuterol (ineffective).

Chemical Groups and Molecular Function

  • Distinctive properties of organic molecules are determined by both the carbon skeleton and the attached chemical groups.
  • Various groups can replace hydrogens in organic molecules.

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