WEEK 2 EXPERIMENT ANSWER SHEET Please submit to the Week 2 Experiment “Submit Assignment” tab no later than Sunday midnight.
SUMMARY OF ACTIVITIES FOR WEEK 2 EXPERIMENT ASSIGNMENT
· Experiment 2 Exercise 1a – Effect of substrate concentration on enzyme function
· Experiment 2 Exercise 1b – Effect of pH on enzyme function
· Experiment 2 Exercise 2 – Cellular Respiration and Photosynthesis
Experiment 2 Exercise 1A: Effect of substrate concentration on enzyme function
Review the Week 2 Experiment Introductions, our online lecture on Energetics and pp 80 - 82 in your book. For this exercise, we are going to look at the effect of temperature on enzyme function, while holding enzyme concentration, pH and temperature constant. Open the following website to get started:
Bioman. No date. Enzymatic https://biomanbio.com/HTML5GamesandLabs/LifeChemgames/enzymatichtml5page.html
Procedure
A. Click on “Start a New Game” and follow the on-screen instructions.
B. When you get to the “Main Menu”, click on “Experiments”. You will have to click twice.
C. Click “OK” and follow the on-screen instructions. Please note that you do not need to submit the answers from the quiz.
Questions
1. In this Experiment, which variable is the dependent variable and which is the independent variable (2 pts)?
2. Describe the relationship between temperature and enzyme activity (1 pts).
3. What is the temperature and enzyme activity was the highest (1 pts)?
4. What happens when the temperature becomes too high? Cited your sources. (2pts)
5. What happens when the temperature become too low? Cited your sources. (2pts)
Experiment 2 Exercise 1b: Effect of pH on enzyme function
Be sure to review the Week 2 Experiment Introduction, our online lecture on Energetics and pp 80 - 82 in your book. For this experiment, we are going to look at the effect of pH on enzyme function, while holding enzyme concentration, substrate concentration and temperature constant. Go to:
Procedure
A. Continue from the previous experiment by clicking “OK”. Follow the on-screen instructions.
Questions
1. In this Experiment, which variable is the dependent variable, and which is the independent variable (2 pts)?
2. Describe the relationship between pH and enzyme activity. At what pH did you see optimum enzyme activity (2 pts)?
3. Explain your results based on what you have learned about enzymes this week and the factors that affect their function. Cite your source (4 pts).
Experiment 2 Exercise 2: Cellular Respiration and Photosynthesis
In this exercise, you will test the following hypothesis by predicting results based upon the experimental set-up.
a. Hypothesis - Aquatic animals require the presence of plants to provide them with oxygen (via photosynthesis) needed for cellular respiration.
The relationship mentioned in the hypothesis is illustrated in the diagram below:
image1.png
In our experiment, we are using an aquatic environment, but the concepts are the same. The snails and Elodea will produce carbon dioxide via cellular respiration. The Elodea will use this carbon dioxide in photosynthesis to produce sugars. The oxygen required for cellular respiration will be generated by the Elodea via photosynthesis.
image2.png
One rack of tubes (1D-4D) will be placed in the dark box for 24 hrs, while the other rack (1L-4L) will be exposed to light.
Indicator is added to detect the presence of carbon dioxide.
· Blue - no carbon dioxide
· Green - medium level of carbon dioxide
· Yellow - high level of carbon dioxide
Table 3. Predicted Results (6 pts).
Test Tube
Contents
Starting Color
Predicted End Color
Explain
1D
0 snails, 0 Elodea
Green
2D
1 snails, 0 Elodea
Green
3D
0 snails, 1 Elodea
Green
4D
1 snails, 1 Elodea,
Green
1L
0 snails, 0 Elodea,
Green
2L
1 snails, 0 Elodea,
Green
3L
0 snails, 1 Elodea
Green
4L
1 snails, 1 Elodea
Green
Questions
1. In which treatment(s) did you see the greatest amount of carbon dioxide present? Explain why this was true for each treatment that had the greatest amount; be specific (3 pts).
2. In which treatment(s) did you see the least amount of carbon dioxide present? Explain why this was true for each treatment that had the least and explain what happened to the carbon dioxide that had been present (2 pts).
3. Was there any difference in your results between tubes 3D and 3L? If so, describe what the difference was and why (2 pts).
4. Based on your results, how do you know that snails produce carbon dioxide (2 pts)?
5. What was the purpose of tubes 1D and 1L (2 pts)?
Week 2 Experiment Grading Rubric
Component
Expectation
Points
Experiment 2 Exercise 1A
Demonstrates an understanding of the relationship between temperature and enzyme function and the ability to conduct an experiment and interpret results (Questions 1-5).
8 pts
Experiment 2 Exercise 1B
Demonstrates an understanding of the relationship between pH and enzyme function and the ability to conduct an experiment and graph and interpret results (Questions 1-3).
8 pts
Experiment 2 Exercise 2
Follows instructions, correctly sets up experiment and records data (Tables 3).
6 pts
Experiment 2 Exercise 2
Demonstrates an understanding of the relationship between cellular respiration and photosynthesis and interpretation of experimental results (Questions 1-5)
11 pts
TOTAL
33 pts
Updated October 2013