Answer:
2.) However, after a certain temperature (about 45°C) the bonds within the enzyme molecule that keep its shape, begin to vibrate so violently that they break. This results in the enzyme losing its shape, including the active site's shape. This is called denaturation. As the substrate can no longer fit into the active site, the activity of the enzyme dramatically decreases. Once all the enzyme molecules are denatured, the enzyme activity will completely cease.
Step-by-step explanation:
Enzymes are organic catalysts which speed up the rate of chemical reactions. Since most enzymes are proteins, they have specific structures which relates to their catalytic abilities.
When heat above the optimal temperature of activity (about 45°C and above) is applied to an enzyme, the structural integrity of the enzyme molecules are compromised. The various quaternary, tertiary, secondary and structures of the protein are destroyed. This also results in the shape of the active site of the enzyme to be distorted. As a result, substrate cannot bind and the enzyme loses its activity.