When an enzyme is outside the temperature range, pH range, or both in which it normally functions, what happens to cause it to no longer work as expected? Explain your answer in terms of the enzyme's ability to bind to its substrate.

The increase in temperature reflects an increase in the kinetic energy of the molecules, which favors the collision between the enzyme and substrate molecules. If the optimum pH changes, the conformation of the enzyme is altered and the substrate cannot enter its active site.

Explanation:

The relationship between pH and activity depends on the acid-base behavior of the enzyme and the substrate itself. Substrate and enzyme (active center) can contain acidic and basic functional groups, their degree of dissociation being dependent on pH, which will determine, among other aspects, the conformation of the protein, the binding capacity of the substrate to the active center of the enzyme and the transformation capacity of the substrate. The rate of an enzymatic reaction varies with increasing temperature. Such dependence reflects a double effect of temperature: positive at low values, due to the general increase that the speed of any chemical reaction experiences as temperature increases, and negative at high values, due to the thermal denaturation of the enzyme. That is, the speed of an enzymatic reaction increases as the temperature increases within a certain range, reaching a maximum value at the so-called optimal temperature. At higher values the activity decreases because the enzyme, like any other protein, undergoes denaturing processes and, therefore, inactivation.