Biology – 5.1 Enzymes | e-Consult
5.1 Enzymes (1 questions)
1. Predictions:
- Test tube A (4°C): The rate of oxygen production will be very slow. At this low temperature, the kinetic energy of the molecules is low, resulting in infrequent collisions between the enzyme and substrate. The enzyme is also less flexible, hindering optimal substrate fit.
- Test tube B (37°C): The rate of oxygen production will be highest. 37°C is close to the optimal temperature for catalase, allowing for a high rate of effective collisions and efficient enzyme-substrate fit. The enzyme is functioning at its most active.
- Test tube C (70°C): The rate of oxygen production will be very slow or zero. 70°C is significantly above the optimal temperature. The enzyme will have undergone significant denaturation, altering the shape of the active site and preventing effective substrate binding. The enzyme is essentially non-functional.
2. Why Test tube B has the highest rate:
Test tube B (37°C) represents the optimal temperature for catalase. At this temperature, the balance between kinetic energy and enzyme stability is ideal. The enzyme molecules have sufficient kinetic energy for frequent effective collisions, but the enzyme structure is not disrupted, allowing for optimal fit with the substrate. This results in the highest rate of reaction.
3. Why Test tube C has the lowest rate:
Test tube C (70°C) is too hot. The high temperature causes the catalase enzyme to denature. This means the enzyme's tertiary and secondary structures are disrupted, leading to a change in the shape of the active site. The active site can no longer bind to the substrate effectively, reducing the number of effective collisions. Consequently, the reaction rate is significantly reduced, and the enzyme may become completely inactive.