57 Key Terms
- activation energy
- energy necessary for reactions to occur
- active site
- enzyme’s specific region to which the substrate binds
- allosteric inhibition
- inhibition by a binding event at a site different from the active site, which induces a conformational change and reduces the enzyme’s affinity for its substrate
- anabolic
- (also, anabolism) pathways that require an energy input to synthesize complex molecules from simpler ones
- ATP
- adenosine triphosphate, the cell’s energy currency
- bioenergetics
- study of energy flowing through living systems
- catabolic
- (also, catabolism) pathways in which complex molecules break down into simpler ones
- chemical energy
- potential energy in chemical bonds that releases when those bonds are broken
- coenzyme
- small organic molecule, such as a vitamin or its derivative, which is required to enhance an enzyme’s activity
- cofactor
- inorganic ion, such as iron and magnesium ions, required for optimal enzyme activity regulation
- competitive inhibition
- type of inhibition in which the inhibitor competes with the substrate molecule by binding to the enzyme’s active site
- denature
- process that changes a substance’s natural properties
- endergonic
- describes chemical reactions that require energy input
- energy coupling
- process during which energy released by one reaction is used to drive another reaction
- enthalpy
- a system’s total energy
- entropy (S)
- measure of randomness or disorder within a system
- enzyme
- proteins, comprised of amino acid chains, that perform the critical task of lowering the activation energies of chemical reactions inside the cell
- exergonic
- describes chemical reactions that release free energy
- feedback inhibition
- a product’s effect of a reaction sequence to decrease its further production by inhibiting the first enzyme’s activity in the pathway that produces it
- free energy
- Gibbs free energy is the usable energy, or energy that is available to do work
- heat
- energy transferred from one system to another that is not work (energy of the molecules’ motion or particles)
- heat energy
- total bond energy of reactants or products in a chemical reaction
- induced fit
- dynamic fit between the enzyme and its substrate, in which both components modify their structures to allow for ideal binding
- kinetic energy
- energy type that takes place with objects or particles in motion
- metabolism
- all the chemical reactions that take place inside cells, including anabolism and catabolism
- phosphoanhydride bond
- bond that connects phosphates in an ATP molecule
- potential energy
- energy type that has the potential to do work; stored energy
- substrate
- molecule on which the enzyme acts
- thermodynamics
- study of energy and energy transfer involving physical matter
- transition state
- high-energy, unstable state (an intermediate form between the substrate and the product) occurring during a chemical reaction