Sections
Key Terms
Key Terms
- activation energy
- energy necessary for reactions to occur
- active site
- specific region of the enzyme 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 affinity of the enzyme for its substrate
- anabolic
- (also, anabolism) pathways that require an input of energy 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 are broken down into simpler ones
- chemical energy
- potential energy in chemical bonds that is released when those bonds are broken
- coenzyme
- small organic molecule, such as a vitamin or its derivative, which is required to enhance the activity of an enzyme
- cofactor
- inorganic ion, such as iron and magnesium ions, required for optimal regulation of enzyme activity
- competitive inhibition
- type of inhibition in which the inhibitor competes with the substrate molecule by binding to the active site of the enzyme
- denature
- process that changes the natural properties of a substance
- endergonic
- describes chemical reactions that require energy input
- enthalpy
- total energy of a system
- entropy (S)
- measure of randomness or disorder within a system
- exergonic
- describes chemical reactions that release free energy
- feedback inhibition
- effect of a product of a reaction sequence to decrease its further production by inhibiting the activity of the first enzyme 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 energy transferred from one system to another that is not work—energy of the motion of molecules 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
- type of energy associated 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
- type of energy 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