The Pre-lab was due for homework today, so if you were unable to complete it, have it ready for Monday, October 11.
Today, we did a lab involving Enzymes. The Lab is detailed on Pages 24 through 32 in your Unit Packet.
For those of you who don't know, Enzymes are proteins that speed up chemical reactions in cells. Almost all chemical reactions that occur in living organisms (For example, digestion) are catalyzed (sped up) by enzymes. Many factors in the environment of a cell affect the action of an enzyme. For example, enzymes work best at certain pH values and at certain temperatures.
Catalase is an Enzyme found in blood and other cells. It speeds up the breakdown of hydrogen peroxide (the substrate) into water and oxygen. If left to build up within cells, hydrogen peroxide is toxic.
Picture of Catalase Enzyme
Picture of Hydrogen Peroxide
The Materials we needed for the lab were:
1. Catalase (enzyme)
2. 6% hydrogen peroxide solution (substrate)
3. water
4. dropper pipette
5. test tubes
6. 25-mL graduated cylinder
7. metric ruler
8. glass-marking pencil
9. ice bath
10. thermometers
11. warm water bath
12. safety glasses
All materials were provided for us.
For the Lab, we had pre-assigned groups of 4 people each. Specific temperatures were assigned to each group.
In the Enzyme Lab we did,we tried to determine the effect of different temperatures on enzyme activity. In the lab, we subjected the Catalase Enzyme to different temperatures. We then added hydrogen peroxide to the test tube, and we then measured how much activity occurs by measuring the height of the oxygen bubble column in the test tube. The higher the bubble column, the more enzyme activity there was.
The Lab was divided into two sections: Part A: Observe the Catalase Reaction and Part B: How does Temperature affect Enzyme Activity?
Part A: Observe the Catalase Reaction Steps:
1. Put on your gloves and safety goggles
2. With the red marking pencil, label 3 test tubes at the 1 cm and 5 cm levels (Measure from bottom of test tubes.)
3. Fill test tube #1 to the first mark with catalase (enzyme). Then, fill test tube #1 to the second mark with hydrogen peroxide (substrate). Swirl to mix them together. Then wait 20 seconds for the bubbling to occur.
4. Measure the height of the bubble column in mm, then record the data in the first table that corresponds to the lab in the Unit Packet.
5. Next, fill test tube #2 to the first mark with water. the, fill test tube #2 to the second mark with hydrogen peroxide (substrate). Swirl to mix. Wait 20 seconds for bubbling to occur.
6. Measure the height of the bubble column in mm, and record in the first table.
7. Lastly, fill test tube #3 to the first mark with catalase. next, fill Test tube #3 to the second mark with sucrose solution (a different substrate). Swirl to mix. Wait 20 seconds for bubbling to occur.
8. Measure the height of the bubble column in mm, and record it in Table 1 of your Unit Packet.
We then had to answer questions about Part A.
Part B: How does Temperature affect Enzyme Activity? Steps:
1. Formulate a Hypothesis
2. Test your hypothesis. Outline a brief procedure for your experiment.
3. Set up your warm or hot water, or ice bath to achieve your desired temperature.
4. With the red marking pencil, label a new test tube at the 1 cm and 5 cm levels.
5. Fill your test tube to the first mark with catalase enzyme.
6. Place your test tube into the water bath of your assigned temperature for 10 minutes. Monitor the temperature of the catalase until it reaches the desired temperature.
7. After 10 minutes, use your thermometer to record thee actual temperature of the catalase. Remove your test tube from the water bath, and add hydrogen peroxide (substrate) to the second line. Swirl to mix. Wait 20 seconds for bubbling to occur.
8. Measure the height of the bubble column in mm. Make a table of results and record the data in it.
9. Repeat the experiment one more time.
10. Determine your average temperature (Celsius). Record your data on the sheet with the class
data.
For homework, we have to start on the analysis and interpretation questions in our Unit Packet starting on page 27. We do not need to finish it, but simply start it.
- Richard P.
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