BIO
NAME___________________
D I G ES T I O N w i t h o u t I N G ES T I O N L A B
Background
In order to obtain energy and building blocks from food, the digestive system must break down
proteins, fats and carbohydrates. In this process, specific enzymes catalyze hydrolysis reactions in
which food polymers are broken up into monomers. In this lab, you will perform reactions involved in
digestion of carbohydrates, lipids and proteins and observe the results of these reactions.
Prelab
In your lab notebook, begin a new page for this lab with a title, date and partners. Describe the
purpose of this experiment in your own words. Make an outline or flow chart of the procedure you will
use. Be sure to include any safety precautions noted in the lab procedure or mentioned by your
teacher. Finally, create a table in which to record your observations about each reaction. Your table
should have a title, a column or row for listing the reactions, and rows or columns for the observations.
Also answer the following questions:
1. What type of compound and bond is hydrolyzed by amylase? By a protease?
2. Why do some people add lactase to dairy products before they eat them?
3. Why are digestive reactions called hydrolysis reactions?
Procedure
Put on your goggles and apron. Obtain a lab tray for your team.
Digestion 1: Hydrolysis of Protein
A. Cut a piece of hard-boiled egg white into 3 small pieces about 0.5 cm in length and add 1 to
each of 3 test tubes.
B. Add the following solutions to the test tubes:
test tube
solution
1
2 mL water
+ 8 drops 0.5 M HCl
2
2 mL 2% pepsin
+ 8 drops 0.5 M HCl
3
2 mL 2% pepsin
+ 8 drops water
Be careful: remember that HCl is a strong acid and can burn your skin!
C. Place the test tubes in a 37° water bath for 30 minutes or more. Record any changes in the
egg white in each tube.
Digestion 2: Emulsification of fats
Be