Glossary

ACHONDRITE
A differentiated meteorite.
ANTICODON
A triplet of bases in transfer RNA complementary to the codon.
ARCHAEBACTERIA
The organisms that make up one of the biological kingdoms.
ARCHEAN
The period of Earth's history 3.8 to 2.4 billion years ago.
AU
Astronomical Unit, the mean distance between the Earth and the Sun.
BIOCHEMISTRY
The study of the chemical constituents of living matter and of their functions and transformations during life processes.
BIOGENIC ELEMENTS
The elements which make up the bulk of living organisms.
CAI
Calcium-aluminum inclusions found in meteroites.
CODON
A triplet code of bases in DNA which specifies an amino acid in protien synthesis.
D/H
The Deuterium-to-Hydrogen ratio.
DNA
Deoxyribonucleic acid.
EUBACTERIA
All bacteria apart from the archaebacteria.
EUKARYOTE
Cells with a true nucleus and other internal organelles.
FISCHER-TROPSCH REACTION
A process in which carbon monoxide and hydrogen are converted into hydrocarbons and related compounds.
GENOME
The complete set of genes in an organism.
HD/H2
The ratio of deuterated hydrogen to hydrogen.
HETROCYCLIC ORGANIC POLYMERS
Compounds consisting of monomeric units of organic ring molecules in which not all atoms in the ring are alike.
HETROTROPH
Organisms requiring organic compounds as a food source.
IR
The infrared region of the electromagnetic spectrum.
K
The Kelvin, a unit of temperature.
mRNA
Messenger RNA, which directs the synthesis of proteins.
NAD
Nicotinamide Adenine Dinucleotide, a coenzyme involved in redox reactions.
NUCLEOSIDE
The precursor of nucleic acids, consisting of an organic base and a sugar.
NUCLEOSYNTHESIS
The production of elements heavier than hydrogen.
OLIGONUCLEOTIDE
Short chains of nucleic acid monomers.
OLIGOPEPTIDE
Short chains of amino acids.
PAH
Polyaromatic Hydrocarbon.
PHOSPHOMONOESTERASE
A hydrolytic emzyme which releases inorganic phosphate.
PHOTOTROPH
Organisms that derive their energy from light.
PLANETESIMAL
A solar-system body of the order of a kilmetre in size.
PLANETOID
A solar-system body of the order of tens to hundreds of kilometres in size.
PREBIOTIC
The period before the appearance of life on Earth.
PRECAMBRIAN
The period in Earth's history from its formation to 600 million years ago.
PROKARYOTE
Organisms lacking a true nucleus.
PYROLYSIS
The destruction of organic compounds by combustion.
REHOLITH
The surface debris on solar-system objects produced by impacting bodies.
RIBONUCLEOTIDE
A monomereric unit of RNA
RIBOOLIGONUCLEOTIDE
Short chains of ribonucleotides.
RIBOSOME
A cellular partical that is the site of protein synthesis.
RNA
Ribonucleic acid.
RNA polymerase
The enzyme that polymerizes ribonucleotides.
RNase P
tRNA-processing enzyme containing a catalytic RNA subunit.
rRNA
Ribosomal RNA which is involved in protein synthesis.
TEMPLATE
A molecule that is copied to form its complement in nucleic acid synthesis.
THIOL-ESTER
A sulphur-containing ester.
TRANSLATION
The process by which the DNA code specifies the sequence of amino acids.
tRNA
Transfer RNA, which combines the specific amino acid in protein synthesis.
UV
The ultraviolet region of the electromagnetic spectrum.
VAN DER WAALS FORCES
The weak attractive forces between non-polar molecules.