Question

Your assignment in biology lab is to design an experiment that would detect whether a substance is breaking down, or digesting, a protein. Which of the following experimental designs would be your best choice?
A. Test tube A: Water and egg white
Test tube B: Water, egg white, and pepsin.
Procedure: Test the pH of both tubes at the same temperatures for consistency.
B. Test tube A: Water and soy protein
Test tube B: Water, egg white, and pepsin
Test tube C: Water, egg white, acid, and pepsin
Procedure: Observe each test tube for changes in the protein every 15 minutes.
C. Test tube A: Water and egg white
Test tube B: Water, egg white, weak acid, and pepsin
Test tube C: Water, egg white, strong acid, and pepsin
Procedure: Record the mass of the egg white in each test tube before you begin. Measure the egg whites every 15 minutes.

Answer 1

Answer: Option B

Explanation: First we should understand the role of enzyme and acid here. Pepsin is an enzyme which will break down proteins into simple monomers (like amino acids). And, acid causes digestion which means it will break down the protein into its respective elements and compounds. Water will act as a control in this experiment.

Option B is correct because it has all three criteria-                                                                                   1. Control [water + protein]                                                                                                               2. With enzyme [egg white + pepsin]                                                                                           3. With acid and enzyme

So this will give us an idea whether pepsin alone is breaking down the protein or digesting it. And there would be difference in test tube B and C. So this will clear the difference.

Option A is incorrect because it has not mentioned any different test tube for checking what happened with the protein. And, Option C is incorrect because mass of egg white will remain same after digestion also.