Enzyme Lab 1 – Which pineapple juice contains enzymes that digest protein?
Materials
•
•
•
•
•
1 petri dish with jello
1 straw
Sharpie (share with other groups)
Pineapple juice (three kinds)
ruler
Procedure: (10 pts)
1. With your straw make six small “wells”, equal distances apart, in your jello. You’ll do this by
inserting the straw and twisting in up and out. NOTE: this works best if the jello is very cold so
do it as soon as possible.
2. Turn your petri dish over and using a sharpie draw a circle that marks the boundary of your
“well”. Measure the diameter of the well and record it for each well in your data table.
3. Label the wells 1 – 6 and put a name from your group on the top of the dish.
4. Using your data table as a guide, fill the wells with the appropriate kind of pineapple juice. (Juice
is located in the back of the room.
5. Cover your petri dish and return it to the teacher to be stored in the refrigerator for 24 to 48
hours.
6. On Day 2, retrieve your dish from your teacher. Remove the top and gently dump all liquids
down the sink. Replace the top and turn the dish over.
7. Draw a new circle showing the size of the well and measure it. Record your data in your data
table.
8. Answer your analysis questions. Share your data with another group and fill in the other two data
tables using the data from another group.
Name _______________________________
Class Period__________________________
Date __________________
Enzyme Lab Data Sheet
Enzyme Lab 1
Well
Juice
1
2
3
4
5
Diameter Before
Diameter After 24 – 48 hours
Fresh Pineapple Juice
Fresh Pineapple Juice
Canned Pineapple Juice
Canned Pineapple Juice
Frozen Pineapple Juice
6
Frozen Pineapple Juice
1. Was your hypothesis supported by the data? Why or why not?
2. What caused the contents to stay liquid?
Enzyme Lab 2
Well
Temperature
1
Boiling Fresh Juice
2
3
Boiling Fresh Juice
Boiling Fresh Juice
4
5
6
Room Temp. Juice
Room Temp. Juice
Room Temp. Juice
Diameter Before
Diameter After 24 – 48 hours
3. Was your hypothesis supported by the data? Why or why not?
4. What caused the contents to stay liquid?
Enzyme Lab 3
Well
Acid / Base
1
2
3
4
Control with Juice
Control with Juice
Base with Juice
Base with Juice
5
6
Acid with Juice
Acid with Juice
Diameter Before
5. Was your hypothesis supported by the data? Why or why not?
6. What caused the contents to stay liquid?
Diameter After 24 – 48 hours
Enzyme Lab 2 – Effects of temperature on enzymes
Materials
•
•
•
•
•
1 petri dish with jello
1 straw
Sharpie (share with other groups)
Fresh Pineapple juice
Ruler
•
•
•
•
Test tube
Test tube holder
Boiling Water Bath
Thermometer
Procedure:
1. With your straw make six small “wells”, equal distances apart, in your jello. You’ll do this by
inserting the straw and twisting in up and out. NOTE: this works best if the jello is very cold so
do it as soon as possible.
2. Turn your petri dish over and using a sharpie draw a circle that marks the boundary of your
“well”. Measure the diameter of the well and record it for each well in your data table.
3. Label the wells 1 – 6 and put a name from your group on the top of the dish.
4. Place 5 ml of fresh pineapple juice in a test tube and boil it using the water bath in the back of
the room. NOTE: Your pineapple juice must reach 100°C. When reading the thermometer be
sure it is not touching the glass test tube.
5. Place 3-4 drops of boiling juice in wells 1, 2, and 3. Place 3-4 drops of room temperature juice in
wells 4, 5, & 6.
6. Cover your petri dish and return it to the teacher to be stored in the refrigerator for 24 to 48
hours.
7. On Day 2, retrieve your dish from your teacher. Remove the top and gently dump all liquids
down the sink. Replace the top and turn the dish over.
8. Draw a new circle showing the size of the well and measure it. Record your data in your data
table.
9. Answer your analysis questions. Answer your analysis questions. Share your data with another
group and fill in the other two data tables using the data from another group.
Enzyme Lab 3 – Effects of pH on enzymes
Materials
•
•
•
•
•
1 petri dish with jello
1 straw
Sharpie (share with other groups)
Fresh Pineapple juice
Ruler
•
•
•
•
3 test tubes
Bleach (base)
Vinegar (acid)
Water (control)
Procedure:
1. With your straw make six small “wells”, equal distances apart, in your jello. You’ll do this by
inserting the straw and twisting in up and out. NOTE: this works best if the jello is very cold so
do it as soon as possible.
2. Turn your petri dish over and using a sharpie draw a circle that marks the boundary of your
“well”. Measure the diameter of the well and record it for each well in your data table.
3. Label the wells 1 – 6 and put a name from your group on the top of the dish.
4. Label the three test tubes as follows “water”, “bleach”, “vinegar.”
5. Place 3 mL of fresh pineapple juice in all three test tubes.
6. Place 2 mL of bleach into the test tube with pineapple juice labeled “bleach”. Do the same for
the “water” and “vinegar” test tubes; adding the appropriate liquid to the pineapple juice.
7. Place 3-4 drops of liquid from each test tube as follows: In well 1 & 2 place the water solution.
In wells 3 – 4 place the bleach solution; in wells 5-6 place the vinegar solution.
8. Cover your petri dish and return it to the teacher to be stored in the refrigerator for 24 to 48
hours. Clean up your materials and return them for the next class to use.
9. On Day 2, retrieve your dish from your teacher. Remove the top and gently dump all liquids
down the sink. Replace the top and turn the dish over.
10. Draw a new circle showing the size of the well and measure it. Record your data in your data
table.
11. Clean up your materials for the next class to use. Answer your analysis questions. Answer your
analysis questions. Share your data with another group and fill in the other two data tables using
the data from another group.
Lab – Enzyme Labs
Name: ___________________
(75 points)
Pre-Lab Questions:
Directions: Read the background material provided to you. Using this material, your notes, and
text (chapter 3), answer the following questions.
1. By definition, what is an enzyme?
2. (a) Describe what happens when a protein denatures. (You may use a smart phone to look this up it
is not in your book.)
(b) Is the denatured protein still able to function?
3. (a) What is the name of the enzyme we are using in this lab?
(b) What fruit is it found in?
4. (a) What is the protein we are using in this lab?
(b) For this lab, what is our food source for the protein?
5. In your own words, describe what happens to collagen when it is heated.
For Lab 1:
6. Read the procedure for Enzyme Lab 1. Make a hypothesis regarding which of the four juices (water,
fresh pineapple juice, boxed juice, concentrated juice) will be solid and which will be liquid when
you examine your results on Day 2.
7. Why do you hypothesize this?
For Lab 2:
8. Read the procedure for Enzyme Lab 2. Describe what you think the “wells” will look like at Day 2;
Write a hypothesis for which test tube’s contents will be solid or which will be liquid?
9. Why do you hypothesize this?
For Lab 3:
10. Read the procedure for Enzyme Lab 3. Make a hypothesis as to which “wells” (acid, base, control)
will be liquid at Day 2.
11. Why do you hypothesize this?
Enzyme Labs 1-3
Background Information
Pineapples
Pineapple’s lush, tropical sweetness is reason enough to enjoy it any way you can, but this fruit also
contains vitamin C and manganese. This fruit’s most promising nutritional asset, though, may be
bromelain, a natural enzyme found in both the fruit and the stem.
Most of the pineapple consumed in the United States is canned (in the form of juice as well as fruit), but
fresh pineapple is much more flavorful, and , despite its tough bristly shell, is easy to prepare.
The fruit probably first grew wild in parts of South America and then spread to the Caribbean, where
Columbus encountered it. By 1600, early European explorers had carried pineapples as far as China and
the Philippines. In the 18th century, pineapples were taken to the Hawaiian Islands, eventually becoming
the major fruit crop. Hawaiian pineapple producers were the first to can the fruit.
Bromelain
The pineapple plant contains protein-digesting enzymes called, as a group, bromelain. In the health
world, these enzymes are regarded as useful in reducing muscle and tissue inflammation (hence the joint
pain and wound-healing possibilities), as well as acting as a digestive aid. In the cooking world, on the
other hand, bromelain is regarded as the enemy of the gelatin dessert. If you use fresh pineapple in
gelatin, the enzyme eats the protein and the gelatin will not gel—in fact bromelain is measured in units
called GDU, or gelatin digesting units. The classic kitchen trick for getting around this pineapplegelatin incompatibility is to cook the pineapple, thus reducing the power of the bromelain.
Recipes that would highlight the benefits of bromelain start with fresh pineapple (which has two to three
times the amount of bromelain as canned pineapple does), and is then subjected to as little heat as
possible.
Bromelain is used in meat tenderizers, in hill-proofing beer, manufacturing precooked cereals, in certain
cosmetics, and in preparation to treat edema and inflammation.
Gelatin
Gelatin, a familiar, ingredient in cooking, is obtained by boiling the skin, tendons, and ligaments of
animals. As a result, it contains protein called collagen ( a primary component of joints, cartilage, and
nails), and various amino acids (histidine, lysine, leucine, tryptophan, and valine, to name a few).
Remember: amino acids are the building blocks of proteins.
Gelatin has long been a key ingredient for providing support for “jelled” deserts, salads, frozen drinks,
and soft candies such as Gummi Bears. (In fact, the word gelatin is derived from the Latin “gelatus”,
meaning stiff or frozen.)
Scientists have been studying gelatin for centuries. It has no smell or taste of its own, adapting to
whatever it is added to. During the Napoleonic Wars, the French, desperate for nutrition sources during
the English blockade, reportedly first turned to gelatin as a source of protein (albeit a weak one). Gelatin
began its long run as a popular consumable, however, in the 1890’s, when it was first developed and
then heavily promoted as a commercial product by Charles Knox, founder of the Knox Gelatin
Corporation.