Question

This activity includes a number of negative controls. Which tube indicates that the amylase solution was not contaminated with maltose

a. Tube 1 (starch, pH 7.0 buffer)
b. Tube 2 (amylase, starch, pH 7.0 buffer)
c. Tube 5 (deionized water, starch, pH 7.0 buffer)
d. Tube 6 (maltose, pH 7.0 buffer)

Answer 1

Tube 5 (deionized water, starch, pH 7.0 buffer) serves as the negative control indicating that the amylase solution was not contaminated with maltose, since it contains deionized water in place of amylase.

Step-by-step explanation:

The tube that indicates the amylase solution was not contaminated with maltose is Tube 5 (deionized water, starch, pH 7.0 buffer). In an experiment to test for the activity of amylase on starch, it is crucial to include controls that show what would happen in the absence of amylase. Since amylase breaks down starch into maltose, a negative control would need to be a condition where no amylase is present to ensure that any detected maltose is not due to contamination. Tube 5 contains deionized water instead of amylase, hence if maltose is detected in this tube, it would suggest that the amylase solution used in the other tubes might be contaminated.