| organic compounds that are the molecular building blocks of proteins | amino acids |
| the multidisciplinary study of life in the universe: its origin, evolution, distribution, and fate; similar terms are exobiology and bioastronomy | astrobiology |
| evidence of the presence of life, especially a global indication of life on a planet that could be detected remotely (such as an unusual atmospheric composition) | biomarker |
| a molecule that stores information about how to replicate a cell and its chemical and structural components | DNA (deoxyribonucleic acid) |
| a formula for estimating the number of intelligent, technological civilizations in our Galaxy, first suggested by Frank Drake | Drake equation |
| an organism (usually a microbe) that tolerates or even thrives under conditions that most of the life around us would consider hostile, such as very high or low temperature or acidity | extremophile |
| the basic functional unit that carries the genetic (hereditary) material contained in a cell | gene |
| an environment capable of hosting life | habitable environment |
| the region around a star in which liquid water could exist on the surface of terrestrial-sized planets, hence the most probable place to look for life in a star’s planetary system | habitable zone |
| a compound containing carbon, especially a complex carbon compound; not necessarily produced by life | organic compound |
| a combination of carbon and other atoms—primarily hydrogen, oxygen, nitrogen, phosphorus, and sulfur—some of which serve as the basis for our biochemistry | organic molecule |
| a complex sequence of chemical reactions through which some living things can use sunlight to manufacture products that store energy (such as carbohydrates), releasing oxygen as one by-product | photosynthesis |
| a key biological molecule that provides the structure and function of the body’s tissues and organs, and essentially carries out the chemical work of the cell | protein |
| a molecule that aids in the flow of genetic information from DNA to proteins | RNA (ribonucleic acid) |
| the search for extraterrestrial intelligence; usually applied to searches for radio signals from other civilizations | SETI |
| solid, layered rock formations that are thought to be the fossils of oxygen-producing photosynthetic bacteria in rocks that are 3.5 billion years old | stromatolites |
| an organism that can tolerate high temperatures | thermophile |
