Small organic molecules that are needed by certain enzymes for them to function. They participate in catalysis when they bind to the active site of the enzyme and form the active enzyme. Although coenzymes activate enzymes they are not considered as substrates of the reaction. The main function of the coenzyme during catalysis is to act as intermediate carriers of transferred electrons or functional groups in a reaction.Ex: flavin adenine dinucleotide (FAD)Cofactor: An inorganic complement of an enzyme reaction. Cofactors are non-protein compounds. Although, they are involved in catalysis by binding to enzymes at their specific binding sites in order to activate them.Ex: Fe+++ or Fe++ (reacts with cytochromes, hemoglobin, and ferredoxin)Competitive inhibitor: The blocking of the action of an enzyme by a compound that binds to the freeenzyme, preventing the substrate from binding and thus preventing the enzyme from acting on that substrate. The competitive inhibitor is often a substrate analogue and binds at the active site. Saturating concentrations of substrate can remove the inhibitionEndergonic reaction: A reaction that requires energy to be absorbed for it to take place. These reactions are not spontaneous. They require work or energy to get started. Sometimes the initial energy required to get the reaction started is all the energy that is required, while other times the reaction continues to absorb energy throughout the entire process.Exergonic reaction: A reaction where energy is released. Because the reactants lose energy (G decreases), free energy (ΔG) is negative under constant temperature and pressure. These reactions usually do not require energy to proceed, and therefore occur spontaneously. These reactions release energy by breaking less stable chemical bonds and forming more stable bonds. Facultative anaerobe: An organism which can produce energy through aerobic respiration and then switching back to anaerobic respiration depending on the amounts of oxygen and fermentable material in the environment.Ex of facultative anaerobic bacteria: Escherichia coli, Listeria, and CorynebacteriumFermentation: Cellular process that is anaerobic. It is used by certain cells to convert organic food intosimpler compounds. In doing so, chemical energy (e.g. ATP) is generated. Fermentation occurs in fruits, bacteria, yeasts, fungi, as well as in mammalian muscleInduced fit: The process by which an enzyme’s active site conforms to the shapeof the substrate thereby forming the enzyme-substrate complex. This is the least stableconfiguration but also is the most favorable to promote the reaction.