Ch 6: Cellular Thermodynamics Vocabulary

The amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation.

The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.

An organic molecule serving as a cofactor. Most vitamins function as coenzymes in metabolic reactions.

A measure of molecular disorder, or randomness.

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

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

Energy available in molecules for release in a chemical reaction; a form of potential energy.

The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site.

Caused by entry of the substrate, the change in shape of the active site of an enzyme so that it binds more snugly to the substrate.

A metabolic pathway that releases energy by breaking down complex molecules to simpler molecules.

substrate complex

Any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely and reversibly, along with the substrate, during catalysis.

An adenine

The energy that matter possesses as a result of its location or spatial arrangement

A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule to simpler molecules (catabolic pathway).

A process that occurs without an overall input of energy; a process that is energetically favorable.

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.

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 (delta G) equals G(final state) minus G(initial state).

A kind of allosteric regulation whereby a shape change in one subunit of a protein caused by substrate binding is transmitted to all the other subunits, facilitating binding of additional substrate molecules to those subunits.

A nonspontaneous chemical reaction, in which free energy is absorbed from the surroundings.

(1) The overall flow and transformation of energy in an organism. (2) The study of how energy flows through organisms.q

The principle of conservation of energy: Energy can be transferred and transformed, but it cannot be created or destroyed.

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

The capacity to cause change, especially to do work (to move matter against an opposing force).

A molecule (often a reactant) with a phosphate group covalently bound to it, making it more reactive (less stable) than the unphosphorylated molecule.

A spontaneous chemical reaction, in which there is a net release of free energy.

The study of energy transformations that occur in a collection of matter. See also first law of thermodynamics; second law of thermodynamics.

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

The principle stating that every energy transfer or transformation increases the entropy of the universe. Usable forms of energy are at least partly converted to heat.

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.

The reactant on which an enzyme works.

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

Thermal energy in transfer from one body of matter to another.

A substance that reduces the activity of an enzyme by entering the active site in place of the substrate, whose structure it mimics.