Which tube contains both lipase and vegetable oil, providing the substrate for hydrolysis?

• A. Tube 2
• B. Tube 3
• C. Tube 5
• D. Tube 4

Answer: (C)

Lipase can only catalyze the breakdown of triglycerides when both the enzyme and its substrate are present in the same environment. Vegetable oil provides triglycerides, and lipase provides the enzyme that acts on them. When they’re together, lipase cleaves the triglycerides into glycerol and free fatty acids, which can be detected by a pH change or other indicators used in the experiment. If a tube lacks the substrate, or lacks the enzyme, hydrolysis cannot occur because one essential component is missing. Therefore, the tube that contains both lipase and vegetable oil is the one where hydrolysis can happen and be detected, making it the correct choice.