Which types of plants produce an enzyme which
will break down proteins?
QUESTION
• Which types of plants
produce an enzyme which
will break down proteins?
• Do different conditions in
which the enzyme breaks
down protein change the
rate of this break down?
You Decide!
What do you need to know?
All living cells produce enzymes. These enzymes help chemical
reactions happen faster. They lower the amount of energy needed
for a chemical reaction to occur. An enzyme is called a catalyst. A
catalyst speeds up a reaction but does not become part of that
reaction. The enzyme stays the same throughout the whole reaction.
Some plants produce in the fruit that contains enzymes which break
down a type of protein called gelatins. This can result in the gelatin
changing so that it won’t solidify.
Do you know what Jell-O gelatin is really made out of?
Are you ready?
Gelatins are made out of discarded animal
parts – the tough parts: bone and skin. These
tough parts are made of proteins.
Gelatin is a protein. Gelatin gets thick and
jelly like when you cook.
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So…How do they make this jiggly
dessert?
It all started at the Jell-O factory in LeRoy, New
York, which is just west of Rochester.
Gelatin can be extracted from any kind
of animal. Cows are the most common
source.
Commercial gelatin making
starts by grinding up bones.
The
crushed bones are then soaked in a
strong base (high pH). This softens
them. They are then passed through
progressively stronger acid (low pH) solutions until they look nothing
at all like bones. Then the whole mess is boiled for hours to extract
the gelatin…and this part really makes a stink! Finally, the gelatin
layer is skimmed off the boiling pot and dried into a powder.
So…this takes us back to the plant enzymes. How do plants
or the fruit of the plant sometimes affect jell-o when you
make a desert?
In this lab, you will design an experiment to determine which fruits
contain the enzyme which prevents gelatin from forming its gel
state.
What materials will be available for the experiment?
In this lab you will be provided with:
‰ Jell-O
‰ Various types of fruit
‰ Test tubes
‰ Beaker filled with ice
‰ Incubator
Your job is to create a controlled experiment to test for the presence
of this enzyme using fruit and gelatin; once your design is approved
you may test it out!
Use the fill in the blanks template below in order to design your
experiment.
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Experimental Design Matrix
Title of the Experiment: What are you trying to find out?
Ex. The effect of (independent variable) on (dependent variable) in subject.
The effect of ___________________ on _________________ in
___________________.
Question Asked:
Hypothesis: What do you think will happen during the experiment?
If (you do this) , then (this will happen).
If __________________________, then _____________________
_____________________________________________________.
Control: Part of the experiment used as a comparison. Normal conditions
Set up one test tube with _________________________________.
Independent Variable: What are you testing or changing in your experiment?
What are your units of measurement?
The independent variables that will be tested include
______________,_________________, ___________________,
____________________ and ____________________.
Dependent Variable: What results will you measure? What are your units of
measurement?
The dependent variable will be what you observe about the ______.
Constants: List at least five things that it would be important to keep the same
during your experiment so that it will be a fair test of your hypothesis.
The parts of the experiment that will be kept the same throughout
include _______________, _______________ and _____________.
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What are the steps of your procedure?
1. Place ___________ grams of _________________into each of
the test tubes as shown below. Label each test tube A-F.
A
B
C
D
E
F
2. Add _______________ grams of each fruit to the different test
tubes. Record each in the data table below and write or draw
your observations.
Test Tube Type of Fruit Added
(____ grams)
A
Observations
B
C
D
E
F
What is your conclusion?
The Jell-O appeared _________________ when adding _________
_____________________________________________________
____________________________________________________.
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What do you now know about the enzymes in the fruit of
plants?
If your experiment was successful, pineapple and papaya should
have been shown to contain an enzyme that does not allow gelatin
to gel.
What might you conclude about pineapple and papaya?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
Read this…….
Pineapple, papaya and Spanish moss belong to the same family of
plants. The pineapple (the most famous) was used in this
experiment because it is known to contain a protease (enzyme that
breaks down protein).
Pineapples were thought to have originated in Brazil and came to the
United States in the 1950’s. They became the second most
important fruit to the United States. Hawaii led the world in harvest
of high quality pineapples. However, times have changed and now,
all canned pineapple comes from overseas, largely from the
Philippines.
The protease in pineapple has also been found useful for reducing
muscle and tissue inflammation. It can also be used as a digestive
aid in people. It works by breaking down fibrin, a blood-clotting
protein. Fibrin may prevent good circulation in some people.
Plants may contain chemicals that could be useful in medicines which
have not been discovered yet. On the other hand, many plants may
be poisonous to humans and other animals. Often both the helpful
and harmful outcomes result from the enzymes found in plants.
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Now…..What do you know?
1. What is an enzyme?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
2. Why didn’t the gelatin with the pineapple gel?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
3. What could you do to fresh pineapple to allow the gelatin to
gel?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
4. What is a possible source of error for this lab experiment?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
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