Biology Assignment

Lab 5- Enzymes Handout

Instructions for Part 1: Enzyme Lab Simulation
Go to this website: https://sites.google.com/site/biologydarkow/lactase-enzyme-simulation
1. Start with the initial lactose at 500 mg/dL and the pH at 7. Do not vary these parameters while testing for temperature, they are environmental controls. The temperature is in degrees Celsius.
Share your method for calculating the rate of reaction for the first 3 minutes before going on. The units should be mg/dL glucose per minute.
Vary the temperature by 20oC.Run each experiment 5 times (for reliability in the results.) Record the rate of reaction in the table below. The rate of reaction should be in mg/dL of glucose per minute.

0oC 20oC 40oC 60oC 80oC
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Mean
2. Create an appropriately labeled graph to illustrate the sample means of the five temperatures tested.
3. What are the results of the simulation? What is the optimal temperature? Explain.
4. Explain why your results of the optimal temperature of the lactase enzyme make sense for the human enzyme? Explain the results in terms of the structure and function of proteins.
5. Propose an appropriate control treatment for the experiment, and describe how the control treatment would increase the validity of the results.
6. What is the chemical reaction that lactase catalyzes?
7. Why would having the enzyme lactase as an adult be an evolutionary advantage?
8. Explain how the structure of an enzyme relates to how well the function catalyzes chemical reactions.
9. Predict how the milk digestion is affected in individuals that lack functional copies of the gene encoding lactase. Justify your response.

Instructions for Part 2: Design your own experiment
In groups, design an experiment that you can conduct at home to look at enzyme activity. An example would be:
• Saliva contains amylase, get food and chew until it tastes sweet
• Repeat experiment with cold vs hot food
• Repeat experiment with a different variable of your choice

Before you begin your experiment, answer the following questions:
1. What background data information did you use when designing your experiment and developing a hypothesis?
2. What is your hypothesis?
3. What predictions are you making based on your hypothesis and background knowledge?
4. Outline the procedures of the experiment that you will be following. Be specific and be sure to include your sample size.

After you complete the experiment, answer the following questions:
5. Describe your results.
6. Graph your results. Be sure to label the x-axis and y-axis (with units) and give the graph a descriptive title. Using Microsoft excel is preferred for drawing a graph (it is more precise) but you may draw the graph by hand instead if you wish (it must be neat and precise).
7. What is/are your conclusion(s)?
8. What future experiments can you do? Is there anything you would do differently next time?