1. At high temperatures, the rate of enzyme action decreases because the increased heat
A.
causes denaturation of the enzyme. To understand why the rate of enzyme action decreases at high temperatures, it's important to know that enzymes are proteins. Proteins have a specific three-dimensional structure that is essential for their function.
At low to moderate temperatures, the increased heat energy causes the enzymes to vibrate more, which can actually increase the rate of enzyme action. This is because the increased vibration helps substrates bind to the active site of the enzyme more frequently and with greater ease.
However, at high temperatures, beyond a certain point called the enzyme's optimal temperature, the increased heat disrupts the weak bonds that maintain the protein's three-dimensional structure. This can lead to a process called denaturation, where the enzyme loses its shape and becomes nonfunctional.
Denaturation of the enzyme prevents the substrates from properly binding to the active site, hindering the catalytic action of the enzyme. As a result, the rate of enzyme action decreases at high temperatures.