free energy

(redirected from Free energy (disambiguation))
Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.

energy

 [en´er-je]
power that may be translated into motion, overcoming resistance or causing a physical change; the ability to do work. Energy assumes several forms; it may be thermal (in the form of heat), electrical, mechanical, chemical, radiant, or kinetic. In doing work, the energy is changed from one form to one or more other form(s). In these changes some of the energy is “lost” in the sense that it cannot be recaptured and used again. Usually there is loss in the form of heat, which escapes or is dissipated unused; all energy changes give off a certain amount of heat.ƒ

All activities of the body require energy, and all needs are met by the consumption of food containing energy in chemical form. The human diet comprises three main sources of energy: carbohydrates, proteins, and fats. Of these three, carbohydrates most readily provide the kind of energy needed to activate muscles. Proteins work to build and restore body tissues. The body transforms chemical energy derived from food by the process of metabolism, an activity that takes place in the individual cell. Molecules of the food substances providing energy pass through the cell wall. Inside the cell, chemical reactions occur that produce the new forms of energy and yield by-products such as water and waste materials; see also adenosine triphosphate.
free energy (Gibbs free energy (G)) the energy equal to the maximum amount of work that can be obtained from a process occurring under conditions of fixed temperature and pressure.
nuclear energy energy that can be liberated by changes in the nucleus of an atom (as by fission of a heavy nucleus or by fusion of light nuclei into heavier ones with accompanying loss of mass).

free en·er·gy (F),

a thermodynamic function symbolized as F, or G (Gibbs free energy), = H - TS, where H is the enthalpy of a system, T the absolute temperature, and S the entropy; chemical reactions proceed spontaneously in the direction that involves a net decrease in the free energy of the system (that is, ΔG < 0).

free en·er·gy

(F) (frē en'ĕr-jē)
A thermodynamic function symbolized as F, or G (Gibbs free energy), =H-TS, where H is the enthalpy of a system, T the absolute temperature, and S the entropy; chemical reactions proceed spontaneously in the direction that involves a net decrease in the free energy of the system (i.e., ΔG < 0).

free energy

the amount of energy that is available for work when released in a chemical reaction. For example, when a molecule of ATP is hydrolysed to ADP + P, the free energy released is about 34 kJ.

energy

power that may be translated into motion, overcoming resistance, or effecting physical change; the ability to do work. Energy assumes several forms; it may be thermal (in the form of heat), electrical, mechanical, chemical, radiant or kinetic. In doing work, the energy is changed from one form to another or to several forms. In these changes some of the energy is 'lost' in the sense that it cannot be recaptured and used again. Usually there is loss in the form of heat, which escapes or is dissipated unused. All energy changes give off a certain amount of the energy as heat.
All activities of the body require energy, and all needs are met by the consumption of food containing energy in chemical form. The animal diet comprises three main sources of energy: carbohydrates, proteins and fats. Of these three, carbohydrates most readily provide the kind of energy needed to activate muscles. Proteins work to build and restore body tissues. The body transforms chemical energy derived from food by the process of metabolism, an activity that takes place in the individual cell. Molecules of the food substances providing energy pass through the cell membrane. Inside the cell, chemical reactions occur that produce the new forms of energy and yield by-products such as water and waste materials. See also adenosine.

dietary energy
the total energy intake in the diet is the gross energy. Digestible energy is gross energy less fecal energy. Metabolizable energy is digestible energy less that lost in fermentation in the gut, energy lost in urine. Net energy is metabolizable energy less energy used in specific dynamic action response. Expressed as joules, calories or occasionally therms (1 calorie=4.18 joule).
energy density
see caloric density.
energy feeds
feeds with a high carbohydrate content and therefore low fiber (<18%) and="" protein=""><20%)>
free energy
the energy equal to the maximum amount of work that can be obtained from a process occurring under conditions of fixed temperature and pressure.
nuclear energy
energy that can be liberated by changes in the nucleus of an atom (as by fission of a heavy nucleus or by fusion of light nuclei into heavier ones with accompanying loss of mass).
nutritional energy deficiency
causes loss of body weight, milk, egg and wool production. Continued for long periods or severe restriction causes particular metabolic upsets in pregnant and lactating ewes and cows—see pregnancy toxemia, acetonemia (2); in neonates, hypoglycemia. In others causes emaciation, inanition, starvation.
energy production
production of ATP through oxidative phosphorylation or anaerobic glycolysis.
energy requirements
generally vary between species and particularly between individuals. They are determined by many factors, especially age, level of activity, physiological status and body size, specifically body surface area. The basal energy requirement (BER) is the level required by a healthy animal at complete rest in a neutral environmental temperature. It can be calculated by using several formulae, based on body weight or body surface area, which is then used in the further calculation of the maintenance energy requirement (MER) which takes into account the individual animal's level of activity or disease status.
energy reserves
any reduced carbon stored in compounds such as fatty acids in triacylglycerols of adipose tissue, glucose in glycogen, and amino acids in protein releases energy, ultimately in the form of ATP on oxidation of the carbon.
energy transfer
conversion of energy from one form usually chemical in the form of ATP to another usually chemical, but can be electrical, mechanical or heat energy.