binations of amino acids in peptide linkages, that contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur

Protonated Having protons added to a base

Protoplanetary disk The disk of dust and gas surrounding a star out of which planets form

Psychrophilic Requiring low temperatures for growth

Radiolysis The breakdown of molecules as a result of exposure to ionizing radiation

Retrotransposon A transposon copied from RNA with the use of reverse transcriptase

Ribosome A minute, round particle composed of RNA and protein found in the cytoplasm of living cells and active in the synthesis of proteins

RNA Ribonucleic acid

rRNA Ribosomal RNA

Serpentinization reaction A hydrothermal reaction by which magnesium-rich silicate minerals are converted into or replaced by serpentine minerals

Siderophore A molecular receptor that binds and transports iron

Silane Any of a group of silicon hydrides having the general formula SiH that are analogous to the paraffin hydrocarbons

Sphalerite The primary ore of zinc, occurring in usually yellow-brown or brownish-black crystals or cleavage masses, essentially ZnS with some cadmium, iron, and manganese

Stereochemistry The branch of chemistry concerned with the study of how atoms or molecules are affected by their three-dimensional spatial arrangement, e.g., the study of stereoisomers

Synthetic biology Engineering of biological components or systems that are not known to nature or the reengineering of existing biological components

Tagish Lake (meteorite) A unique carbonaceous chondrite collected very soon after falling to Earth in a remote part of northwestern Canada in January 2001

Thermophile An organism adapted to living in high-temperature environments

Thioester Compound resulting from the bonding of sulfur with an acyl group with the general formula R-S-CO-R′

Tholin A term used in planetary science to refer generally to organic heteropolymers; the reddish tar-like organic residue created in simulations of the action of ultraviolet radiation on gases typically found in planetary environments

Thymidine A nucleoside, C10H14N2O5, composed of thymine and deoxyribose

Vesicle A microscopic volume defined by a boundary structure; examples include self-assembled vesicles bounded by a membranous lipid bilayer, and small cavities formed in volcanic rock by entrapment of a gas bubble during solidification

Vitrification The process of liquid water moving directly into the glassy state without ice crystal formation

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