Metabolism Vocab

Activation energy: the amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation

Active site: the specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs.

Allosteric regulation: the binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site

Anabolic pathway: a metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules.

ATP (adenosine triphosphate): an adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells

Catabolic pathway: a metabolic pathway that releases energy by breaking down complex molecules into simpler molecules

Catalysis: a process by which a chemical agent called a catalyst selectively increases the rate of a reaction without being consumed by the reaction

Catalyst: a chemical agent that selectively increases the rate of a reaction without being consumed by that reaction

Chemical energy: energy available in molecules for release in a chemical reaction; a form of potential energy

Competitive inhibitor: a substance that reduces the activity of an enzyme by entering the active site in place of the substrate, whose behavior it mimics.

Enzyme: a macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction. Most enzymes are proteins

enzyme-substrate complex: a temporary complex formed when an enzyme binds to its substrate molecule(s)

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

Free energy: the portion of a biological system’s energy that can perform work when temperature and pressure are uniform throughout the system. The change in free energy of a system is ∆G

kinetic energy: the energy associated with the relative motion of objects. Moving matter can perform work by imparting motion to other matter

Metabolic pathway: a series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule into simpler ones (catabolic pathway)

Metabolic rate: the amount of energy an animal uses in a unit of time

Metabolism: the totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism

Noncompetitive inhibitor: a substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing the enzyme’s shape so that the active site no longer effectively catalyzes the conversion of substrate to product

Potential energy: the energy that matter possesses as a result of its location or spatial arrangement

Product: a material resulting from a chemical reaction

Reactant: a starting material in a chemical reaction

Second law of thermodynamics: the principle stating that every energy transfer or transformation increases the entropy of the universe. Usable forms of energy are at least partially converted to heat

Substrate: the reactant on which the enzyme works

Thermodynamics: the study of energy transformations that occur in a collection of matter