30.6: Key Terms
( \newcommand{\kernel}{\mathrm{null}\,}\)
- amino acids
- organic compounds that are the molecular building blocks of proteins
- astrobiology
- the multidisciplinary study of life in the universe: its origin, evolution, distribution, and fate; similar terms are exobiology and bioastronomy
- biomarker
- 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)
- DNA (deoxyribonucleic acid)
- a molecule that stores information about how to replicate a cell and its chemical and structural components
- Drake equation
- a formula for estimating the number of intelligent, technological civilizations in our Galaxy, first suggested by Frank Drake
- extremophile
- 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
- gene
- the basic functional unit that carries the genetic (hereditary) material contained in a cell
- habitable environment
- an environment capable of hosting life
- habitable zone
- 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
- organic compound
- a compound containing carbon, especially a complex carbon compound; not necessarily produced by life
- organic molecule
- a combination of carbon and other atoms—primarily hydrogen, oxygen, nitrogen, phosphorus, and sulfur—some of which serve as the basis for our biochemistry
- photosynthesis
- 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
- protein
- 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
- RNA (ribonucleic acid)
- a molecule that aids in the flow of genetic information from DNA to proteins
- SETI
- the search for extraterrestrial intelligence; usually applied to searches for radio signals from other civilizations
- stromatolites
- 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
- thermophile
- an organism that can tolerate high temperatures