Answer:
Enzymes rely on molecular movement and collisions with the compounds they are meant to bind with -- called substrates -- so they can speed up certain chemical reactions. Increases in temperature increase molecular activity, and can result in a higher rate of collisions between enzymes and substrates. If the temperature rises too high, however, the enzymes could become denatured, and the positive effects of the temperature increase could be nullified.
Step-by-step explanation:
Many enzymes lose function at lower and higher temperatures. At higher temperatures, an enzyme's shape deteriorates. Only when the temperature comes back to normal does the enzyme regain its shape and normal activity unless the temperature was so high that it caused irreversible damage.