Answer:
Allosteric (noncompetitive) inhibition results from a change in the shape of the active site when an inhibitor binds to an allosteric site. When this occurs the substrate cannont bind to it's active site due to the fact that the active site has changed shape and the substrate no longer fits. Allosteric activation results when the binding of an activator molecule to an allosteric site causes a change in the active site that makes it capable of binding substrate.