An allosteric site is a site on an enzyme, unrelated to its active site, which can bind an effector molecule.

A symmetric thin biconvex lens is cut into four equal parts by two planes AB and CD as shown in the figure. If the power of the original lens is 4D, then the power of a part of the divided lens is:

All reactants need to overcome certain energy, better known as activation energy in order to form products. This activation energy is the difference between the energy of the transition state and the reactant species.
Catalysis of chemical reactions is generally divided into two categories: