AP BIOLOGY

Detailed explanation-1: -The proteins in enzymes are usually globular. The intra-and intermolecular bonds that hold proteins in their secondary and tertiary structures are disrupted by changes in temperature and pH. This affects shapes and so the catalytic activity of an enzyme is pH and temperature sensitive.

Detailed explanation-2: -Enzymes are also sensitive to temperature. Many work best at temperatures close to body temperatures and most lose their ability to catalyse if they are heated above 60 or 70 degrees Celcius. Graph of enzyme-catalysed reaction rate against temperature.

Detailed explanation-3: -pH is a major factor affecting the activity of enzymes. The ionization of amino acid molecules and atoms occurs when the pH is altered, thereby affecting the structure and form of proteins and hence disrupting their activities.

Detailed explanation-4: -Each enzyme work bests at a specific pH value. The optimum pH for an enzyme depends on where it normally works. For example, enzymes in the small intestine have an optimum pH of about 7.5, but stomach enzymes have an optimum pH of about 2. In the graph above, as the pH increases so does the rate of enzyme activity.