So far we have been talking about molecules that are a part of
living organisms, yet are not "vital” in the way that
we sense enzymes and nucleic acids to be. For all their useful properties,
carbohydrates and lipids still are conventional organic molecules,
and seem to belong to the test tube as much as to the cell. They
do not have that aura of “specialness” that envelops
No one has ever suggested seriously that sugars and fats are "alive,"
but this property has been claimed (naively) at times for both proteins
and nucleic acids.
The difference that we instinctively recognize between carbohydrates,
lipids, and other organic molecules on the one hand, and proteins
and nucleic acids on the other, is that the latter carry information
in their structure, in a sense that is not true for any other molecules.
This concept of information creates a qualitative difference between
proteins and nucleic acids, and all other molecules, and makes them
suitable as the basis for a chemistry of life. What this information
is and how it is stored and used is the subject of the next chapters.