hydrogen cycle
41tricarboxylic acid cycle — Biochem. See Krebs cycle. [1940 45] * * * or Krebs cycle or citric acid cycle Last stage of the chemical processes by which living cells obtain energy from foodstuffs. Described by Hans Adolf Krebs in 1937, the reactions of the cycle have been… …
42Childe Cycle — The Childe Cycle is an unfinished series of science fiction novels by Gordon R. Dickson. The name Childe Cycle is an allusion to Childe Roland to the Dark Tower Came, a poem by Robert Browning, which provided considerable inspiration for elements …
43Cell division cycle 7-related protein kinase — Cell division cycle 7 homolog (S. cerevisiae), also known as CDC7, is a human gene.cite web | title = Entrez Gene: CDC7 cell division cycle 7 homolog (S. cerevisiae)| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView… …
44Carbon cycle — The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth.The cycle is usually thought of as four major reservoirs of carbon interconnected by… …
45Reverse Krebs cycle — The reverse Krebs cycle (also known as the reverse tricarboxylic acid cycle, the reverse TCA cycle, or the reverse citric acid cycle) is a sequence of chemical reactions that are used by some bacteria to produce carbon compounds from carbon… …
46Human impacts on the nitrogen cycle — Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation (Galloway 2003). As a consequence of anthropogenic inputs, the global nitrogen cycle (Fig. 1) has been significantly altered over… …
47carbon cycle — n. 1. the cycle by which plants through photosynthesis use atmospheric carbon dioxide to produce carbohydrates, which are in turn metabolized by animals to decomposition products that return carbon dioxide to the atmosphere 2. a cyclic series of… …
48carbon cycle — noun Date: 1912 1. the cycle of carbon in the earth s ecosystems in which carbon dioxide is fixed by photosynthetic organisms to form organic nutrients and is ultimately restored to the inorganic state (as by respiration, protoplasmic decay, or… …
49carbon cycle — car′bon cy cle n. 1) biochem. the biological cycle by which atmospheric carbon dioxide is converted to carbohydrates by plants and other photosynthesizers, consumed and metabolized by organisms, and returned to the atmosphere through respiration …
50carbon cycle — /ˈkabən saɪkəl/ (say kahbuhn suykuhl) noun 1. Biology the circulation on earth of carbon atoms, from the atmosphere through plants and animals back into the atmosphere. 2. Astrophysics a cycle of nuclear transformations, with the release of… …
