Manipulated? Measured? B. EFFECT OF TEMPERATURE ON THE RATE OF ENZYME REACTION a. Procedure 1. Choose a concentration of amylase that had an endpoint time of 60 to 90 seconds in Part A. This will probably be either 1.0 or 2.0 mg/ml. Only one amylase concentration will be used for this exercise. Pipette exactly 1 ml of this amylase concentration into each of 6 clean test tubes. 2. Obtain 6 clean test tubes and add 2 ml of starch solution and 2 ml of pH 7.0 buffer to each. You now have 6 identical test tubes with amylase and 6 identical test tubes with starch and buffer. 3. Place a pair of test tubes (an amylase test tube and a starch/buffer test tube) in each of the following temperatures: 100°C, 60°C, 45°C, 37°C, ice and room temperature. Allow 10 minutes for samples to reach the correct temperature. 4. Follow the timing procedure in part A and determine the endpoint times for each pair. To conserve time, if endpoint has not been reached in 500 seconds, STOP, and record the end time as 500+ seconds. **Remember to keep tubes in the heated or cooled bath water and return the contents of the dropper after each drop, so that the temperature will not change during the experiment. 5. Record all data and answer questions below. b. Results 1. Record your data below. Temperature (°C) O 25 37 45 60 85 Endpoint time in Seconds 255 50 100 374+ 500+ 59 2. Plot a graph comparing the temperature with the endpoint. The values of the independent variable (temperatures) should be plotted on the horizontal or X axis of the graph. The endpoints (values of the dependent variable, or data) should be plotted on the vertical or Y axis. c. Questions 1. What is the temperature optimum for this exercise? (At what temperature is the rate maximum?) 2. Based on your data, predict what the endpoint would be at a temperature of 50°C. 3. Why does the reaction go slower at temperatures cooler than the optimum? Why does the reaction go slower, or not happen at all, at temperatures much warmer than the optimum? 5. During the exercise, what variables are held constant? What variables are manipulated? What variables are being measured? Held constant? Manipulated? Measured? 6. Predict what would happen if you boiled the enzyme tube before the reaction and then held the reaction at 37°C? Explain. 60

Manipulated? Measured? B. EFFECT OF TEMPERATURE ON THE RATE OF ENZYME REACTION a. Procedure 1. Choose a concentration of amylase that had an endpoint time of 60 to 90 seconds in Part A. This will probably be either 1.0 or 2.0 mg/ml. Only one amylase concentration will be used for this exercise. Pipette exactly 1 ml of this amylase concentration into each of 6 clean test tubes. 2. Obtain 6 clean test tubes and add 2 ml of starch solution and 2 ml of pH 7.0 buffer to each. You now have 6 identical test tubes with amylase and 6 identical test tubes with starch and buffer. 3. Place a pair of test tubes (an amylase test tube and a starch/buffer test tube) in each of the following temperatures: 100°C, 60°C, 45°C, 37°C, ice and room temperature. Allow 10 minutes for samples to reach the correct temperature. 4. Follow the timing procedure in part A and determine the endpoint times for each pair. To conserve time, if endpoint has not been reached in 500 seconds, STOP, and record the end time as 500+ seconds. **Remember to keep tubes in the heated or cooled bath water and return the contents of the dropper after each drop, so that the temperature will not change during the experiment. 5. Record all data and answer questions below. b. Results 1. Record your data below. Temperature (°C) O 25 37 45 60 85 Endpoint time in Seconds 255 50 100 374+ 500+ 59 2. Plot a graph comparing the temperature with the endpoint. The values of the independent variable (temperatures) should be plotted on the horizontal or X axis of the graph. The endpoints (values of the dependent variable, or data) should be plotted on the vertical or Y axis. c. Questions 1. What is the temperature optimum for this exercise? (At what temperature is the rate maximum?) 2. Based on your data, predict what the endpoint would be at a temperature of 50°C. 3. Why does the reaction go slower at temperatures cooler than the optimum? Why does the reaction go slower, or not happen at all, at temperatures much warmer than the optimum? 5. During the exercise, what variables are held constant? What variables are manipulated? What variables are being measured? Held constant? Manipulated? Measured? 6. Predict what would happen if you boiled the enzyme tube before the reaction and then held the reaction at 37°C? Explain. 60

3-2-1 Code It

6th Edition

ISBN:9781337660549

Author:GREEN

Publisher:GREEN

Chapter17: Cpt Pathology And Laboratory

Section: Chapter Questions

Problem 15MC

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