Enzyme Virtual Lab

Virtual Lab: Enzyme Controlled Reactions

Read the purpose and objectives, then click on the black TV on the right hand side of the screen. Click the Play button and watch the animation. Scroll to the bottom of the page and Click “Information” to read about enzymes and substrates. Then answer these questions on your paper.

  1. What are enzymes?
  2. What is a catalyst?
  3. What happens to an enzyme during a reaction?
  4. What is a substrate?
  5. What happens to a substrate during a reaction?

Now it’s time to do the experiment! Each test tube already has the same amount of enzyme in it. Click the up or down arrows to change the pH of each test tube. Pick an amount of substrate to add. You need to click and drag the paper onto the test tube. USE THE SAME AMOUNT OF SUBSTRATE FOR EACH TEST TUBE.

  1. How much substrate did you use?
  2. Write down the pH for each test tube.

Click on the computer monitor to see how many molecules of the product were produced. YOU MUST COPY DOWN THIS INFORMATION IN A TABLE ON YOUR PAPER RIGHT NOW. If you don’t copy this down, it will be lost and you will have to go back and do the experiment over again.

When you are finished copying the table, click the Reset button at the bottom of the screen. Repeat the experiment but this time, keep the pH the same and use a different amount of substrate.

  1. What pH did you use?
  2. Write down the amount of substrate for each test tube.

Again, click on the computer monitor and COPY DOWN THE INFORMATION IN A DIFFERENT TABLE ON YOUR PAPER.

Go here to make your graphs.. Or you can open a new tab in Internet Explorer and go to http://nces.ed.gov/nceskids/createagraph/default.aspx. Make your graphs and print them or copy them onto graph paper that I have provided for you. You’ll need to staple them to your first paper.

Answer these Analysis questions on your paper.

  1. Describe the relationship between substrate concentration and the initial reaction rate of an enzyme-catalyzed reaction. Is this a linear relationship? What happens to the initial reaction rate as substrate concentration increases?
  2. What is the maximum initial reaction rate for this enzyme at pH 7?
  3. Explain why the maximum initial reaction rate cannot be reached at low substrate concentrations.
  4. What does your data indicate about the optimum pH level for this enzyme-catalyzed reaction?
  5. Enzymes function most efficiently at the temperature of a typical cell, which is 37 degrees Celsius. Increases or decreases in temperature can significantly lower the reaction rate. What does this suggest about the importance of temperature-regulating mechanisms in organisms? Explain.