Lactase Enzyme Lab Design

Hypothesis: The higher the temperature the less time it takes lactase to break down lactose into Galactose and glucose.

Manipulated Variables: Temperature of the lactose solution

Responding Variable: The amount of time it takes lactase to break down lactose into galactose and glucose.

Controlled Variables: Type of reagent strips; Type of Thermometer; Amount of milk per trial; Type of Lactose drops; Room Temperature; Air Pressure 

Prediction: The milk with the most temperature (100F) will take the least time to get broken down into galactose and glucose.

        This is because rise in temperature increases activity of the enzyme, as the higher the temperature the more kinetic energy the enzyme and the substrate molecules have. This means that more enzyme substrate complexes are likely to form. The increase in movement of the molecules enables a higher chance of the substrate molecules colliding with the enzymes molecules, with sufficient energy, to overcome activation energy, and therefore combining at the active site.

Materials:

Lactase drops

4 glucose reagent strips

4 test tubes

Stirring rod

Thermometer

Graduated cylinder

Milk samples at different temperatures (20F, 40F, 60F, 80F, 100F)

China marker

Illustration:

Procedures:

1. Mark four test tubes at 2 ml.  You can do this by measuring 2 ml of water in a graduated cylinder.  Pour the water into one of the test tubes; use the china marker to show the level.  Now mark the other four in the same fashion.  (throw away the water)
2. Label each test tube to indicate the temperature of the milk in each.
3. Get one sample of milk from the prep table; using only 2 ml.  Record the temperature
4. Use a reagent strip to measure the glucose concentration of the milk and record. (throw away the used strip)
5. Add one drop of lactase to the test tube.  Shake or stir to be sure that it is evenly distributed. Wait 3 minutes. Measure the glucose concentration again. Record the measurement and throw away the used strip.
6. Repeat with the three other milk samples.
7. Don’t forget to take multiple trials (3-5).
8. When you finish collecting data, don’t forget to clean the work station