Enzymes

Enzymes--Controlling Cellular Reactions

Goals for the lesson:

1.  Describe the function of enzymes and relate their structure to their function.

2.  Using examples, explain the relationship between enzymes, substrate and active site; enzyme, active site and competitive inhibitor; enzyme, allosteric site and noncompetitive inhibitor.

3.  Collect and analyze data on enzyme activity to make generalizations about environmental conditions that affect enzyme activity.

Activity 1:
Plug your earbuds or headphones into your device and watch the video below to 5:18 (stop the video at this point.)




After watching the video, go to http://tinyurl.com/enzymeshcs, download and SAVE the document to your Google drive.  You will use this document for your responses.

Complete Activity 1.

Activity 2:

You and your fellow scientists will now observe the very reaction that was discussed in the video.  Potato cells, like most living cells, contain the enzyme catalase.  As described in the video catalase causes hydrogen peroxide to be broken down into water and oxygen.   At your table you have the following materials:



Beaker of 3% hydrogen peroxide (H2O2)
Dropper for the hydrogen peroxide
6 test tubes
Test Tube Rack
Marker
Ruler
Sample of mashed raw potato, with no extra treatment
Dropper for this potato sample
Sample of mashed raw potato, with an additional treatment
Dropper for this potato sample

Working with your fellow scientists, complete the following steps:
Part A.
1.  Using the graduated dropper in the plain potato sample, place 1 mL of potato mixture into one of the test tubes.
2.  Add 5 drops of hydrogen peroxide being careful to observe the "foam/gas" column that is created.
3.  Mark the test tube at the height of the foam column.  Begin all measurements at the bottom of the test tube.
4.  Use the ruler to measure the height of the foam column to the nearest tenth of a centimeter.
5.  Record this measurement in the Google Form below.
6.  Repeat steps 1 - 5 using two or the remaining five test tubes.  (You will do a total of three trials with the untreated potato mixture.)
7.  Record all data in the Google Form below.

Part B.
You and your fellow scientists have also been given a sample of potato with one of the four treatments listed below:

• Potato mixture that was heated
• Potato mixture that was kept in the freezer and on ice
• Potato mixture that was mixed with vinegar (lowering the pH)
• Potato mixture that was mixed with baking soda (raising the pH)

1.  Follow the exact steps in part A, steps 1 - 7, with the potato treatment that has been assigned to your table.  You will take measurements from three trials.

2.  Record the measurements from each of the three trials in the CORRECT PLACE on the Google form below.

Bring all of your text tubes and materials to the front of the room and place in the dirty glassware container.

You can see the results from all of the trials in the spreadsheet below.


Activity 3:
Compare the height of the foam column of the potato mixture without any treatment and with each of the four treatments, heat, ice, vinegar and baking soda.

Go to your enzymes Google doc and answer the questions under activity 3.


Activity 4: The Control of Enzyme Activity
In this part of the lesson we will focus on how enzyme activity can be slowed or stopped.  Go back to the video above and begin watching the video from time stamp 7:59 until 10:05.

You have a bag of enzyme activity models made of swim noodles and some labels.

Create the scenarios described on your response sheet and use the labels to appropriately label the model. Use your device to make a picture of the scenario using your device and then paste it in the appropriate place on your response sheet.