Biology
Experiment
by Zane
Introduction
The action of pepsin on
egg white protein
In this experiment, we will see how pepsin acts on egg white,
which contains a lot of protein. By doing this experiment, we
can learn about the first steps of protein digestion and
understand why enzymes like pepsin are essential for our
bodies to absorb nutrients.
This simple experiment will give us valuable insights into how
our bodies get the essential nutrients from the food we eat. It
can also have practical applications in nutrition, medicine,
and enzyme research, helping us understand how to support
healthy digestion and nutrient absorption.
Materials
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Fresh egg white from a raw egg
Test tubes or small glass containers
Pepsin solution
Hydrochloric acid (HCl) solution
pH indicator
Water bath or incubator set to body
temperature (37°C or 98.6°F)
Procedure
01
Prepare the pepsin solution: If you don't have a
pre-made pepsin solution, dissolve pepsin
powder in water according to the
04
manufacturer's instructions. The concentration
Place all the test tubes in a water bath or
incubator set to body temperature (37°C or
98.6°F). This temperature represents the
normal temperature of the stomach.
can vary depending on the specific experiment
goals.
02
Divide the fresh egg white into several
portions and place each portion into
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Let the experiment run for a specific period,
such as 1 hour or longer, to allow pepsin to
act on the egg white protein.
separate test tubes or small glass containers.
03
Add the pepsin solution to each test tube
containing egg white. If you're using the
simulated acidic environment, add it to the
test tubes as well. Leave one test tube as a
control where you don't add any pepsin.
06
After the designated time, observe and compare the
contents of the test tubes. You should notice changes in
the appearance and consistency of the egg white in the
tubes containing pepsin. The egg white will be partially
digested and may have turned into a semi-transparent,
gel-like substance due to the breakdown of the protein
into smaller peptides.
Result
• Tube A : The change from a cloudy
suspension to a clear solution shows
that the solid particles of egg protein
have been digested to soluble
products.
• Tube B & C : The gel-like substance formed
in the presence of pepsin indicates that the
enzyme has started breaking down the egg
white protein. The breakdown of protein
molecules into smaller protein fragments is
the initial step in protein digestion.
• Tube D : In the test tube where egg white was
present without any added pepsin, there were
no significant changes observed. This served as
the control, confirming that the observed
changes in the experimental tubes were due to
the action of pepsin.
Thank
you!
By Zane