carboxylic acid - An organic acid characterized by one or more COOH groups.
aliphatic hydrocarbon - An organic compound characterized by straight chains of carbon atoms. Alkanes, alkenes, and alkynes are types of aliphatic molecules.
aromatic hydrocarbon - A class of organic compound containing at least one benzene ring (C2H6). Multiply-ringed compounds of this type are known as polycyclic aromatic hydrocarbons, abbreviated as PAHs. PAHs are ubiquitous, and are found, for example, in burned toast and the interstellar medium. They have also been identified in some martian meteorites but are apparently absent (as are all other organic molecules) in surface dust on Mars.
amine - An organic compound which can be derived from ammonia (NH3) by replacement of one or more hydrogens by organic radicals.
amino acid - An organic compound that contains one or more basic amino (NH) groups and one or more carboxyl (COOH) groups. Roughly 80 amino acids are found in nature, but only 20 are used by life to construct proteins.
amide - a class of organic compound containing the CONH2 radical.
purine - a heterocyclic compound containing pyrimidine (C4H4N2) and imidazole (C3H4N2) rings.
alcohol - a class of organic compound containing hydroxyl (OH) groups.
aldehyde - a class of organic compound containing the CHO radical.
carbonyl - a compound that contains a CO group.
ketone - A class of organic compound containing C, O, and at least two additional molecular groups. Ketones are important intermediates in the synthesis of organic compounds.
homologous series - This refers to a series of molecules (homologues) that have a fundamental building block on which additional groups are placed. Examples include compounds with various chain lengths as in table 10.5.1 of the paper.
enantiomer - this a compound which is a "mirror image" of another compound, in that the two compounds have the same composition but two configurations that can be superimposed by the action of a mirror-like reflection (as in our left and right hands). The ability of some molecules to be represented by left & right-handed symmetry is also known as chirality. Examples of enantiomers or chiral compounds include "right-handed" (D) and "left-handed" (L) amino acids. Life uses only L-amino acids. An approximately equal mixture of L- and R-handed molecules is known as a racemic mixture.
NMR spectrum - A spectrum produced by nuclear absorption at characteristic radio wavelengths by the application of a magnetic field.
catalysis - This is the process by which an action of a substance (such as the surface of a mineral grain) speeds up a chemical reaction.
activation energy - This refers to an energy barrier which must be overcome in order to make a process occur. Examples of such processes include chemical reaction, diffusion, and crystal nucleation.
del D - this is the ratio of heavy hydrogen (deuterium, or D) to normal hydrogen expressed in parts per thousand; the del notation is the same as for oxygen-isotope ratios.
del 13C - this is the ratio of 13C to 12C expressed
in parts per thousand; the del notation
is the same as for oxygen-isotope ratios.