BIO CHP 3 - Enzymes and Energy

III. Enzymes and Energy

A. Introduction
-- thermodynamics - the study of energy transformations
-- enzymes - biological catalysts that facilitate reactions by lowering the necessary activation energy - energy needed to be absorbed by the reactants to break the bonds already in place

B. Structure and Function of Enzymes
-- Most enzymes are protein, though some RNA molecules have been found to have enzymatic activity.
-- The almost always large protein is folded so that the active site, where the substrate, or reactant, binds, is accessible.
-- "lock-and-key" theory/model - demonstrates how an enzyme interacts with its substrate: shape of active site matches the shape of the sunstrate exactly.
-- enzymes have specifity, meaning that one enzyme can catalyze only one reaction or a set of related reactions - it benefits the cell because it allows the cell to control different reactions independently by regulating the activity or quantity of the enzyme.
-- Enzymes can be used again, so they typically do not need to be made in large quantities.