Chapter 6 Terms Flashcards
Allosteric site
Site on an allosteric enzyme that binds an effector molecule; binding alters the activity of the enzyme.
Active Site
Region of an enzyme where the substrate binds and where the chemical reaction occurs.
Chemical energy
Energy associated with the interaction of atoms in a molecule.
Coenzyme
Nonprotein organic molecule that aids the action of the enzyme to which it is loosely bound.
Cofactor
Nonprotein assistant required by an enzyme in order to function; many cofactors are metal ions, others are coenzymes.
Competitive Inhibition
Form of enzyme inhibition where the substrate and inhibitor are both able to bind to the enzyme’s active site. Only when the substrate is at the active site will product form.
Denatured
Loss of a protein’s or enzyme’s normal shape so that it no longer functions; usually caused by a less than optimal pH and temperature.
Electron transport chain
Process in a cell that involves the passage of electrons along a series of membrane-bound electron carrier molecules from a higher energy to a lower energy level; the energy released is used for the synthesis of ATP.
Endergonic reactions
Chemical reaction that requires an input of energy; opposite of emerging reaction.
Energy of activation
Energy that must be added in order for molecules to react with one another.
Entropy
Measure of disorder or randomness in a system.
Enzyme inhibition
Means by which cells regulate enzyme activity; may be competitive or noncompetitive inhibition.
Exergonic reactions
Chemical reaction that releases energy; opposite of endergonic reaction.
First law of thermodynamics
Shs
Free energy
Energy in a system that is capable of performing work.
Induced fit model
Change in the shape of an enzyme’s active site that enhances the fit between the active site and its substrate(s).
Metabolic pathway
Series of linked reactions, beginning with a particular reactant and terminating with an end product.
Metabolism
The sum of chemical reactions that occur in a cell.
Noncompetitive inhibition
Form of enzyme inhibition where the inhibitor binds to an enzyme at a location other than the active site; while at this site, the enzyme shape changes, the inhibitor is unable to bind to its substrate, and no product forms.
Oxidation
Loss of one or more electrons from an atom or molecule; in biological systems, generally the loss of hydrogen atoms.
Oxidation-reduction reaction
A paired set of chemical reactions in which one molecule gives up electrons (oxidized) while another molecule accepts electrons (reduced); commonly called a redux reaction.
