A group of biochemists investigated the effect of a synthetic inhibitor, Compound K, on starch degradation by salivary amylase. Four reaction tubes were prepared at and with the components listed in the table below:
| Tube | 1% Starch Solution (mL) | Amylase Solution (mL) | Compound K Concentration (mM) |
|---|---|---|---|
| Tube 1 | 5.0 | 0.0 | 0.0 |
| Tube 2 | 5.0 | 1.0 | 0.0 |
| Tube 3 | 5.0 | 1.0 | 0.1 |
| Tube 4 | 5.0 | 1.0 | 0.5 |
The concentration of remaining starch in each tube was recorded after 10 minutes. Which tube served as the negative control to establish whether starch degrades spontaneously without the enzyme present?
- Tube 1Answer
- BTube 2
- CTube 3
- DTube 4
Answer
Tube 1 served as the negative control to test for spontaneous starch degradation in the absence of the enzyme.
The tube containing starch solution and buffer but no salivary amylase (Tube 1) serves as the negative control. By withholding the enzyme while keeping temperature, pH, and substrate volume constant, researchers can measure background or spontaneous starch breakdown and confirm that enzyme action is required for degradation.
Step-by-Step Solution
Key Concept
Negative Control and Baseline Determination