Which of the following statements about different types of enzyme inhibition are correct? Competitive inhibition occurs when a substrate competes with an enzyme for binding to an inhibitor protein. Competitive inhibition occurs when the substrate and the inhibitor compete for the same active site on the enzyme. Noncompetitive inhibition of an enzyme cannot be overcome by adding large amounts of substrate. Competitive inhibitors are often similar in chemical structure to the substrates of the inhibited enzyme. Noncompetitive inhibitors often bind to the enzyme irreversibly.