Enzymes are committed biological catalysts that complete organic work within cells. In this activity, students investigate the impact of pepsin, a protease, ~ above albumin, wealth protein in pet cells. Pepsin, one enzyme uncovered in the cradle tracts the animals, catalyzes the digestion of food proteins into peptides containing important amino acids. The price at i m sorry enzymes function is affected by numerous factors, including environmental temperature, ecological pH, ion concentration, existence of inhibitory chemicals, and concentrations that the enzyme or its substrate.

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Albumin Suspension (see “Teacher preparation” section below)

Distilled Water

Teacher preparation

Prepare an albumin suspension by separating egg white skin - man (albumin) native yolks and adding 20 mL the distilled water come the albumin. You can use 1 egg because that every 4 rap groups.

Prepare 0.1 M hydrochloric acid solution and also 1% pepsin solution. Come prepare her 1% pepsin solution, dissolve 0.1 g the powdered pepsin in 9.9 mL of distilled water.


This activity requires the usage of hazardous components. Be certain to review all district and department guidelines including the use of the materials detailed above.


Label 5 check tubes “1,” “2,” “3,” “4,” and also “5.”

Place around 5 mL the egg white (albumin) suspension right into each check tube.

Add 3 autumn of dilute hydrochloric acid to pipe 3 and also 4.

Using a syringe, location 1 mL of 1% pepsin systems in a clean test tube and heat it over a small Bunsen flame until the fluid boils. Add the boiled pepsin to the egg white suspension in tube 5.

Fill the 250-mL beaker halfway v water. Place the manufacturer on a warm plate come prepare a water bathtub that will sustain a temperature of about 40° C.

Add 1 mL that 1% pepsin systems to tube 2 and also 4 only.

Place every 5 pipe in the water bath because that 5 minutes.

After 5 minutes, eliminate the tubes from the water bath and also replace castle in the test pipe rack. To compare the illustration of the contents and fill in her table the results.

Data Table
Sample Data Table*

*results will vary


The suspension turns from a cloudy, milky appearance to clear as pepsin, a protease, breaks down the albumin. Students need to observe the pepsin appears to function much more effectively in ~ an acidic pH when contrasted with the other groups. Pipe 4 models conditions present in the stomachs of animals during digestion. The results of this examination should command students to additional questions about the problems under which enzymes are able to function.


Students can design an experiment to present how enzyme task is affected by other components (such as temperature, light, or contending chemicals).

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Students can style an experiment to check the result of antacid assets on the digestion of proteins in the stomach.

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