| Gibbs energy of activation | The Gibbs energy that must be added to that already possessed by a molecule or molecules in order to initiate a reaction. (05 Mar 2000) |
|---|---|
| renewable energy resource | <ecology> An energy resource replenished continuously or that is replaced after use through natural means. Sustainable energy. Renewable energy resources include bioenergy, solar energy, wind energy, geothermal power, and hydropower. (25 Jun 1999) |
| resonance energy transfer | <technique> Transfer of energy from one fluorochrome to another. The emission wavelength of the fluorochrome excited by the incident light must approximately match the excitation wavelength of the second fluorochrome. If light at the second emission wavelength is detected, it implies that the two fluorochromes were physically within a few nanometres. Used as a technique to probe protein or cell interactions. (25 Jun 1999) |
| chemical energy | Energy liberated or absorbed by a chemical reaction, e.g., oxidation of carbon, or absorbed in the formation of a chemical compound. (05 Mar 2000) |
| conservation of energy | The principle that the total amount of energy in a closed system remains always the same, none being lost or created in any chemical or physical process or in the conversion of one kind of energy into another, within that system. (05 Mar 2000) |
| conservation of energy resources | Planned management, use, and preservation of energy resources. (12 Dec 1998) |
| potential energy | <chemistry> Energy due to position, it is stored energy which can be used to do work. (09 Jan 1998) |
| primary energy | <radiobiology> Energy before conversion. For instance, the United States uses about 30,000 megajoules of electricity per capita per year, but electricity is generally obtained by converting other forms of energy (primarily chemical/heat) at an efficiency of around 30%, so the U.S. Consumes 90,000 megajoules of primary energy per capita for electrical use. (Total U.S. Primary energy consumption is 300,000 megajoules per capita.) (09 Oct 1997) |
| Helmholtz energy | Energy equivalent to the internal energy minus the entropy contribution (TS). (05 Mar 2000) |
| protein-energy malnutrition | The lack of sufficient energy or protein to meet the body's metabolic demands, as a result of either an inadequate dietary intake of protein, intake of poor quality dietary protein, increased demands due to disease, or increased nutrient losses. (12 Dec 1998) |
| high energy bond | <chemistry> Chemical bonds that release more than 25kJ/mol on hydrolysis: their importance is that the energy can be used to transfer the hydrolysed residue to another compound. The risk in using the term is that students may think the bond itself is different in some way, whereas it is the compound that matters. Hydrolysis of creatine phosphate yields 42.7kJ/mol, of phosphoenolpyruvate, 53.2, ATP to ADP, 30.5: the latter is important because it shows that energetically the hydrolysis of creatine phosphate will suffice to reconstitute ATP, hence the use of creatine phosphate in muscle. (18 Nov 1997) |
| high energy compounds | Classically, a group of phosphoric esters whose hydrolysis takes place with a standard free energy change of -5 to -15 kcal/mol (or, -20 to -63 kJ/mol) (in contrast to -1 to -4 kcal/mol or, -4 to -17 kJ/mol) for simple phosphoric esters like glucose-6-phosphate or alpha-glycerophosphates), thus being capable of driving energy-consuming reactions in living cells or reconstituted cell-free systems; adenosine 5'-triphosphate, with respect to the beta-and gamma-phosphates, is the best known and is regarded as the immediate energy source for most metabolic syntheses. The general types are acid anhydrides, phosphoric esters of enols, phosphamic acid (R-NH-PO3H2) derivatives, acyl thioesters (e.g., of coenzyme A), sulfonium compound's (R3-S+), and aminoacyl esters of ribosyl moieties. See: high energy phosphates. (05 Mar 2000) |
| high energy particle generating unit | A machine capable of providing highly energised radiation for the purposes of radiotherapy treatment. (16 Dec 1997) |
| high energy phosphate bond | See: high energy phosphates. (05 Mar 2000) |
| high energy phosphates | Those phosphate's that, on hydrolysis, yield an unusually large amount of energy; e.g., nucleotide polyphosphates such as ATP, enol phosphate's such as phosphoenolpyruvate. See: high energy compounds. Synonym: energy-rich phosphates. (05 Mar 2000) |