Enzymes and Energy
In general, enzymes are protein molecules which must be folded in a specific three-dimensional shape in order to function properly. Certain environmental parameters can affect enzyme activity, including pH and temperature. If an enzyme’s shape changes significantly and it can no longer function, the enzyme is said to have become denatured.
The enzyme pancreatic amylase is manufactured and secreted by the pancreas into the duodenum (the large, beginning portion of the small intestine). Pancreatic amylase breaks down starch into maltose, a disaccharide. Pepsin is an enzyme that is released by the epithelium of the stomach, and functions in the stomach to break down proteins into smaller polypeptide units.
The following graphs show the activities of various enzymes under various environmental conditions.
Graph 2 depicts the activities of three enzymes. Which curve illustrates the functioning of human DNA polymerase, which functions in the nucleus of cells?
|D||None of the above could represent the activity of human DNA polymerase.|
Since humans are endotherms and maintain a constant body temperature of approximately 370 C (98.60 F), all human enzymes should share this optimal temperature. Curves A and C depict very different optimal temperatures.