Effector molecule binding changes the behavior of enzymes by altering the equilibrium between the tense (T) state and the relaxed (R) state. Effectors are classified as either homotropic or heterotropic.

Match each description with homotropic effectors(1), heterotropic effectors(2), or both(3). Some statements may not describe either type of effector.

a) an enzyme substrate

b) accounts for the sigmoidal nature of a velocity versus substrate concentration curve

c) alters the Vmax of an enzyme

d) works by altering the T/R ration

e) alters the Km of an enzyme