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Biology 14 Terms
Term | Definition |
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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 |
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 | Spherical in shape and are composed of many protein molecules that are organized as membranes |
Coacervate | a mass of colloidal substances held together by electrostatic attraction |
Ribozyme | a type of RNA that can act as an enzyme |
Archaea | Related group of unicellular organisms, many of which thrive under extremely harsh environmental conditions |
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 |
Endosymbiosis | a mutually beneficial relationship in which one organism lives within another |