What does acid do to egg whites?

Procedure

1. Predict the effect pepsin will have on egg white and how you will be able to tell.

2. Prepare 8 small test tubes (10 mL size), each with an equal-sized cube of hard-boiled egg white. Make sure the piece of egg white is small enough to fit inside the tube.

3. Prepare the tubes as follows:

Tube	Solution	Food
tube 1 & 2	5 mL water	-
tube 3 & 4	2.5 mL water + 2.5 mL 0.2% hydrochloric acid	egg
tube 5 & 6	2.5 mL 1% pepsin + 2.5 mL 0.2% hydrochloric acid	egg
tube 7 & 8	2.5 mL 1% pepsin + 2.5 mL 0.2% hydrochloric acid	potato

4. Vortex the tubes to mix the contents thoroughly.

5. Leave the odd numbered tubes at room temperature and place the even numbered tubes in the incubator at 37^oC.

6. Let the tubes incubate overnight. Observe the tubes the next day and record your observations.

Questions

1. a) Describe the appearance of the egg white and the liquid in tubes 1-6. Account for any differences by explaining the specific effect pepsin is having on the egg white?(digesting into smaller proteins)

b) Do these results support or refute your prediction?

2. a) Why were tubes 1/2 and tubes 3/4 used?

b) Why was egg white used? (contains the protein albumin)

3. a) Why was the experiment performed at two different temperatures?

b) Describe and explain the effect, if any, of temperature. Was this expected?

4. Which test tube most closely resembles the conditions in the human digestive system? (tubewith pepsin + acid at 39^oC)

5. What do you think happened in tubes 7 and 8.