Enzymes: What’s in your spit?

In this lab students will investigate a few of the different enzymes from our body. You will learn how these enzymes work and how their activity is dependent on factors such as heat, pH, and concentration.

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Student Version

Teacher Version

Recommended Prerequistes:
  • none!
Key Concepts:
  • Enzymes are proteins that speed up chemical reactions, and are found in all living organisms because they are important in every day functions like digestion and blood clotting. They also act like scissors and cut bonds between molecules.
  • Accelerating chemical reactions is referred to as catalysis, and because enzymes take part in a chemical reaction, but are not destroyed in the process, enzymes are referred to as catalysts.
  • The shape of each enzyme allows it only to interact with a specific molecule – called a substrate (though the enzyme can act with many substrates at the same time) – that makes the enzyme specific for a particular type of chemical reaction. Think of the enzyme as a “lock” and the substrate as the “key”. Only that certain “key” (substrate) will fit into that specific “lock” (enzyme).
  • ½ Fresh pineapple
  • 1 Orange
  • 1 Apple
  • Cold water available
  • Microwave
  • Jello
  • 100 mL graduated cylinder
  • Flour (Starch)
  • Sugar
  • 8 Small cups per group
  • Yeast (Catalase)
  • Iodine
  • Hydrogen peroxide
  • Eye dropper
  • Vinegar
We want your feedback! Please leave a reply below with your comments, questions, or suggestion to help us improve the lab.

4 Replies to “Enzymes: What’s in your spit?”

  1. I will be trying this lab this week. I’m super excited! Last week we tested “vomit” for the presence of different macromolecules and now we are spitting in cups! I’m so excited to be the gross teacher!

    • We’re so glad you tried out our lab! We’d love to hear your comments about your experience with the lab. We would also love to see and try out your “vomit” lab – we love being the gross science teachers too! You can shoot us an e-mail at teachlabsci@stanford.edu.

  2. I am looking for new enzyme lab from the ones I’ve done in previous years just to add more spice to the unit and this lab looks like it will be a lot of fun or “gross” the students out since they get to spit in class.

    I’m going to give it a try. Thank you for putting it online.

    • We are so excited that you are going to give our lab a try! Let us know how it goes – we love to get feedback to improve our labs!

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