All terms in this list:

energy: the capacity to cause change, especially to perform work.

kinetic energy: The energy of moition; the energy of a mass of matter that is moving. Moving matter does work by imparting moition to other matter.

Heat: Thermal energy; the amount of energy associated with the movement of the atoms and the molecules in a body of matter. Heat is energy in its most random form.

Chemical Energy: Energy available in molecules for realease in a chemical reaction; a form of potential energy.

Cellular respiration: The aerobic harvesting of energy from food molecules;the energy releasing chemical breakdown of food molecules (glucose) and the storage of potential energy in a form that cells can use to preform work.

entropy: A measure of a disorder. one form of disorder is heat, which is random molecular motion.

First law of thermodynamics: the principle of conservation of energy. Energy can be transferred and transformed, but it cannot be created or destroyed.

Potential Energy: The energy that matter possesses because of its location or arrangment. EX: Water behind a dam possesses this kind of energy, so do chemical bonds.

Second law of thermodynamics: The principle stating that every energy conversion reduces the order of the universe, increasing its entropy. Ordered forms of energy are at least partly converted to heat.

Thermodynamics: The study of energy transformation that occurs in a collection of matter.

Activation energy: The amount of energy that reactants must absorb before a chemical reaction will start.

ATP: adenosine triphosphate, the main energy source for cells.

endergonic reaction: An energy-requiring chemical reaction, which yields, products with more potential energy than the reactants.

energy coupling: In cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction.

enzyme: a macromolecule, usually a protein, that serves as a biological catalyst, changing the rate of a chemical reaction without being consumed by the reaction.

exergonic reaction: An energy-releasing chemical reaction in which the reactants contain more potential energy than the products. The reaction releases an amount of energy equal to the difference in potential energy between the reactants and the products.

metabolic pathway: A series of chemical reactions either builds a complex molecule or breaks down a complex molecule into a simpler compund.

metabolism: the totality of an organism's chemical reactions.

phosphorylation: the transfer of a phosphate group, usually from ATP, to a molecule.

Active Site: the part of an enzyme molecule where a substrate molecule attaches (by means of weak chemical bonds); typically a pocket or groove on the enzyme's surface.

Coenzyme: An organic molecule serving as a cofactor. EX: most vitamins function as coenzymes in important metabolic reactions.

Cofactor: a nonprotein molecule or ion that is required for the proper functioning of an enzyme.

competitive inhibitor: a substance that reduces the activity of an enzyme by binding to the enzyme's active site in place of the substrate.

feedback inhibitor: A method of metabolic control in which a product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

induced fit: the change in shape of the active site of an enzyme, caused by entry of the substrate, so that is binds more snugly to the substrate.

Substrate: (1) a specific substance (reactant) on which an enzyme acts. (2) a surface in or on which an organism lives.