October 4th, 2022

Big Bang to Humankind

The Importance of Carbon

  • Carbon is found in:
    • DNA
    • Proteins
    • Carbohydrates
    • Lipids
  • Valence electrons: electrons in the outermost shell
    • Participate in bonding
  • Ionization energy decreases with atomic size - further from the pull of the nucleus
  • Types of bonds
    • Ionic bonds: one molecule just takes the electron from another molecule
      • Like NaCl
      • Magnetic based attraction
    • Covalent bonds: electron is shared and orbiting around 2 nuclei
      • Hydrogen forms covalent bonds because it doesn’t give away its only electron
      • Single, double, and triple covalent bonds exist
    • Polar covalent bond: covalent bond but electron is not equally shared
      • Common with Hydrogen
      • Causes partial negative charge / partial positive charge
  • Silicon seems like a similar backbone as Carbon, but when it interacts with water it becomes sand
    • Also it’s too heavy to be a backbone
    • However, there are planets where lakes are hydrocarbon liquid (gas), where silicon could be the backbone of life
  • None of the organic elements have the versatility (4 valence electrons) that Carbon does
  • Chirality
    • When carbon forms 4 separate bonds, it makes a tetrahedral shape
    • Chiral molecules are almost identical, but not because they’re mirror images, and they behave slightly differently
    • They are in tons of key biological molecules
    • Structures are “right handed” and “left handed”
      • DNA is all right handed
      • Proteins and other structures only work on one chirality because it depends on how it fits into the structure