This graphic illustrates the molecular structure of amino acids. Here is what each of the letters inside the spheres stands for:

C = Carbon
O = Oxygen
N = Nitrogen
H = Hydrogen
R = We'll get to that in a minute.

Every amino acid has this basic structure with a positive charge at one end and a negative charge at the other.

"R" is the part of the amino acid molecules that differs from one amino acid to another.

Note that the bond between one atom and another is cone-shaped for most of the molecule. This cone shape represents the fact that the 2 atoms connected by the cone-shape are in flux. The distance is not a fixed, unbending figure, but is more a probability. The bond between carbon and nitrogen is a straight line, indicating less flexibility in the bond, and a distance that is more fixed.

The amino acid structure gives us some clues about life and death. Remember that amino acids account for 75% of the body's dry weight. After death (and after either burial or cremation), we slowly return to the elements. As the amino acid bonds break down, oxygen, nitrogen, and hydrogen become gases that return to the atmosphere, leaving only carbon behind. Thus "dust to dust" is better understood in light of amino acid structure. Only carbon and other minerals remain.

One might say that in life, and in the birth of life... oxygen, hydrogen, and nitrogen (the primary elements of Earth's atmosphere) come together, along with carbon, to form the organized system known as "Life."