Virtual Lab: Enzyme Controlled Reactions

Worksheet

Name ______Period ______

Log on to

Read the purpose and the procedure: Conduct the experiment and fill in the chart.

Table 1: Record your data on the number of product molecules formed per minute obtained from the virtual lab.

# Product Molecules/minute at:

Amount of Substrate
(Lactose) / pH 3 / pH 5 / pH 7 / pH 9 / pH 11
0.5 g
1.0g
2.0g
4.0g
8.0 g

I. Graph your results on logger pro

1. Double click on x axis – title: Amount of substrate units: grams

2. Double click on y axis – title: # product molecules per min

3. Enter all information labeling data sets by the pH

II. When all information is entered

  1. Double click in center of graph
  2. Title your graph (graph titles can be written as (title of Y vs Title of X)
  3. Click bar graph
  4. Click on legend so a key shows up on the graph
  5. Change the top to Axis options
  6. Open each data set and click on y (# product molecules per min) for each data set.
  7. Click ok

Expand graph by clicking on the A at the top of the page

Print graph and attach to back of lab. Be sure to name stamp it, with YOUR NAME.

Click on information at the bottom of the page and fill in the blanks.

How do substrate concentration and pH affect the rate of an enzyme-controlled reaction?

To sustain the processes of______, a typical cell carries out ______of biochemical reactions each ______. Many of these reactions require the help of ______. Enzymes are ______that speed up the rate of chemical reactions. Many important processes in the body involve the work of enzymes, including the ______of nutrients such as carbohydrates, ______and fats.

Enzymes are ______catalysts. A catalyst is a chemical that controls the ______of a reaction, but is itself not ______in the process. Reactions that are accelerated due to the presence of enzymes are known as enzyme-catalyzed reactions.

Enzymes are proteins that accelerate chemical reactions but do not change themselves in the reaction. Enzymes enable molecules to undergo chemical changes, forming new substances called ______. ______are molecules that are acted upon by enzymes. For instance, ______, an enzyme found in saliva, helps break down complex starch molecules (______) into smaller sugar molecules (______). In other biochemical reactions, substrates require assistance of specific enzymes to form new products.

Each substrate fits into an area of the enzyme called the ______. This fitting together is often compared to a ______-______-______mechanism. However, researchers believe that the fit between enzyme and substrate need ______be exact. Enzymes are viewed as ______keys that can shape and conform to the shape of the substrate.

  1. What substrate amount was required to achieve the maximum reaction rate?
  1. At what pH level did the maximum reaction rate occur? ______
  1. In the graph you created in the lab simulation with your data what is the optimal pH for lactase enzyme activity? ______
  1. Consider only the experiment you conducted with 0.5 g. of lactose.
  2. What is the independent variable?
  1. What is the dependent variable?
  1. List two changes you could make in the experimental conditions or variables in this experiment.

1.

2.