Cell Biology/Introduction/The elements of life

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The various elements that make up the cell are:

• 59% Hydrogen (H)
• 24% Oxygen (O)
• 11% Carbon (C)
• 4% Nitrogen (N)
• 2% Others - Phosphorus (P), Sulphur (S), etc.

The difference between these elements is their respective atomic weights, electrons, and in general their chemical properties. A given element can only have so many other atoms attached. For instance carbon (C) has 4 electrons in its outer shell and thus can only bind to 4 atoms; Hydrogen only has 1 electron and thus can only bind to one other atom. An example would be Methane which is CH₄. Oxygen only has 2 free electrons, and will sometimes form a double bond with a single atom, which is an 'ester' in organic chemistry (and is typically scented).

  H
  |
H-C-H
  |
  H

H   H
 \ /
  O

  H
  |
H-C-O-H
  |
  H

As for the organic molecules that make up a typical cell:

• 50% protein
• 15% nucleic acid
• 15% carbohydrates
• 10% lipids
• 10% Other

Here is a list of Elements, symbols, weights and biological roles.