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Biology Ch. 14
Term | Definition |
---|---|
Biogenesis | The theory that living organisms come only from other living organisms |
Spontaneous Generation | An early and now disproved theory that living organisms come to life spontaneously from nonliving material |
Radiometric Dating | A method of determining the absolute age of an object by comparing the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope |
Isotope | An atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass) |
Mass Number | The sum of the numbers of protons and neutrons in the nucleus of an atom |
Radioactive Decay | The disintegration of an unstable atomic nucleus into one or more different nuclides, accompanied by the emission of radiation, the nuclear capture or ejection of electrons, or fission |
Radioactive Isotope | An isotope that has an unstable nucleus and that emits radiation |
Half-Life | The time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope |
Microsphere | A microscopic spherical structure composed of many protein molecules that are organized as a membrane |
Coacervate | A mass of colloidal substances held together by electrostatic attraction |
Ribozyme | A type of RNA that can act as an enzyme |
Archaea | Prokaryotes (most of which are known to live in extreme environments) that are distinguished from other prokaryotes by differences in their genetics and in the makeup of their cell wall; members of the domain Archaea (singular, archaeon) |
Chemosynthesis | The production of carbohydrates through the use of energy from inorganic molecules instead of light |
Cyanobacteria | A bacterium that can carry out photosynthesis, such as a blue-green alga |
Ozone | A gas molecule that is made up of three oxygen atoms |
Endosymbiosis | A mutually beneficial relationship in which one organism lives within another |