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Name___________________________________Period___Date________
Jell-o or Gel-no: Which Fruits Contain the
Protein-Digesting Enzyme?
Gelatin is a protein made from collagen. Proteins are a basic type of matter that make up all living things.
Collagen is a structural protein found in all animals, that helps give animals their structure, or shape. Collagen
can be found in many parts of your body, including your skin, bones, muscles, and cartilage. Gelatin is a form
of collagen that has undergone a chemical reaction to change it slightly and make it able to solidify when you're
cooking with it. The gelatin proteins are like microscopic strands of spaghetti. These long, thin, flexible gelatin
proteins tangle up with one another, the same way strands of cooked spaghetti do when they're all in one pot
together. As the gelatin proteins tangle, they form mesh pockets that trap the water, sugar, and other flavoring
agents that you’ve added to your dessert. The end result is a wiggly-jiggly solid to enjoy.
Now, back to our original question. What happens when you add fruit to your gelatin? Some fruits contain
enzymes called proteases that won’t allow the Jell-o to solidify. Proteases are a special class of protein called
an enzyme that act like a pair of scissors, cutting other proteins up. Could it be that an enzyme in some fruits
will cut up the gelatin and make your dessert runny? This is exactly the question you’ll tackle in this lab. Which
fruits contain proteases that will keep the Jell-O from becoming a solid?
Pre Lab Questions
1) What problem are we going to solve in this lab? ________________________________________________
2) What type of biomolecule are enzymes? _______________________
3) Describe what proteases are and what they do to the collagen in the jello. ____________________________
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4) Based on the introduction, label the enzyme substrate diagram below with the protease enzyme and the
collagen.
5) What is your hypothesis about which fruits will contain the protease enzymes? Why?
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DAY 1 PROCEDURE
1. Label Each Dixie cup with Your Name, period number, and first initial of fruit.
2. Place each piece of fruit into the cup with the corresponding label.
3. A teacher will come around and pour approximately equal volumes of the Jell-O mixture into each cup.
4. Place the Jell-O and fruit mixtures at the center of your table.
5. A teacher will collect the Jell-O cups and refrigerate them for the following day.
DAY 2 PROCEDURE
1. Observe your samples and fill in the table below.
Type of Fruit
Yes or No- Did it become
solid?
Yes or No- Does the fruit contain protease
enzymes?
Post-Lab Assessment:
1) What were we testing in the Jell-O or Gel-No lab? _______________________________________________
2) The enzyme tested in this lab was ______________________ and the substrate was ___________________.
3) The fruit(s) that contain the enzyme was/were ________________________________________________.
How do you know? __________________________________________________________________
4) Describe through pictures what you think was happening between the enzyme and substrate that caused the
Jello to remain a liquid.
5) Reflective Summary (What did you learn from this lab? Be scientific!):
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