Why ASM?

MIT All Small Molecules project

We have classified the chemicals made by life on Earth into three types

Type I: Byproduct from biological energy extraction from chemical potential energy gradients. Examples: include methane from methanogenesis, sulfur dioxide from sulfur oxidation
Type II: Byproduct gases from biomass building. Examples include oxygen from photosynthesis, sulfur from anoxygenic photosynthesis
Type III: Produced for secondary or unknown reasons, such as stress or signaling. Examples include methyl chloride, carbondisulfide, isoprene

This classification is based not on what the chemcials are but on why life makes them, which helps us evaluate whether the same biological need would drive life to make different chemicals on a different world.

(see this paper for a more detailed discussion of the classification)