This small glossary list few words that can be useful for Natural Science students. I hope you will find the word you were looking for.
- abiogenesis
- The emergence of life forms emerging from non-living chemical systems. In contrast with spontaneous generation, abiogenesis is not a process that biologists think continues in a particular environment, such as a planet or moon, once a living system has emerged.
- acetylcholine
- A chemical neurotransmitter. When released onto a muscle, acetylcholine will activate sodium channels to open.
- active transport
- The opposite of passive transport, active transport involves the input of energy (usually in the form of ATP), the building of concentration gradients, and the action of a membrane pump to create high concentrations of molecules.
- adenosine triphosphate
- (ATP) Molecules that provide energy for important chemical reactions within the cell; the main energy currency of the cell.
- adhesion
- The interaction of a molecule with something other than itself, often related to mechanical or electrostatic forces. For example, water forms a meniscus within a glass cylinder due to adhesive forces between the water and glass.
- bacteriophage
- Any of a group of viruses that infect and reproduce in specific bacteria, usually causing their disintegration or dissolution. After the bacterium is destroyed, the bacteriophage is released and can invade surrounding bacteria.
- biogeochemical
- Of or relating to the partitioning and cycling of chemical elements and compounds between the living and nonliving parts of an ecosystem.
- catalyst
- A substance that speeds up the rate of a chemical reaction but that is not used up in the process.
- centrifugation
- The process of uses a rotating force to separate particles according to density.
- chlorofluorocarbons
- Compounds consisting of carbon, chlorine, fluorine, and sometimes hydrogen once used widely as aerosol propellants and refrigerants. lso known as CFCs. The realization that chlorofluorocarbons cause depletion of the stratospheric ozone layer led to a sharp decrease in their use mandated by the Montreal Protocol in 1989.
- conchoidal fracture
- A type of breakage that produces a smooth, curved surface. Conchoidal fracture occurs when a substance has uniform strength in all directions and no pre-existing planes of atomic weakness. This generally occurs in two types of substances: minerals like quartz whose atomic structure consists of equally strong bonds in all directions, and volcanic glass, called obsidian, which has no definitive crystal structure.
- diffusion coefficient
- Developed by Adolf Fick, a mathematical framework stating that the diffusion rate of a substance is proportional to the difference in concentration between the two areas. This means that, if the concentration of a given substance is high in relation to the substance it is diffusing into (e.g., food coloring into water), the process will be faster than if the concentration difference is low (e.g., food coloring into food coloring).
- Doppler effect
- Describes the change in a wave's frequency experienced by an observer moving in relation to the wave's source. In the case that the wave source and observer are moving toward one another, the frequency of the observed waves increases and wavelength decreases. With sound, this would result in an increase in pitch. Conversely, for a wave source and observer moving away from one another, the wave frequency decreases and wavelength increases. With sound, this would result in a decrease in pitch. The Doppler Effect can be experienced with any wave form, including light (see redshift and blueshift).
- electromagnetic radiation
- A series of waves that are propagated by simultaneous, periodic variations of electrical and magnetic fields. Examples of electromagnetic radiation include radio waves, light, X-rays, gamma rays, and others.
- genetic drift
- Changes in gene frequencies due to random events, such as when a small group is isolated from the rest of the population, thus narrowing the gene pool.
- ionic bond
- A chemical bond characterized by electrostatic attraction between ions of opposite charge. The formation of an ionic bond involves a complete transfer of electrons between atoms, and can be predicted when one bonding atom has a much higher electronegativity than the other. Compare to hydrogen bond.
- lenticular
- Shaped like a lens, of or related to a lens; often referring to clouds, galaxies, rock bodies, or small features within rocks.
- oligotrophic
- A water body that is very low in available nutrients, but very high in dissolved oxygen. When nutrient content is very low, plants are not able to grow and survive. Since plants are a critical part of the food chain, this means all other forms of life are also limited. See also: limiting nutrient.
- phylogeny
- The evolutionary history of a group of organisms, or the sequence of events in the evolutionary development of a group of organisms. Phylogeny can also indicate the diagram or depiction of that history, sometimes called an evolutionary tree.
- uniformitarianism
- The fundamental geological principle that the processes that are operating now to shape the world around us have been operating throughout the geologic past as well. This principle was first proposed by James Hutton in the mid-1700s, and implied that the Earth had to be billions of years old to create all of the rocks and structures we see today. Importantly, uniformitarianism does not require that all changes happen at the same rate; some processes are slow, like the deposition of sediment in deltas, others are fast, like volcanic eruptions. This principle is often paraphrased as "The present is the key to the past."
- http://www.visionlearning.com/en/glossary
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