BIO161 Lab Report 4 PDF

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Lab Report #4 Template Part II of Cellular Respiration: Rest vs Exercise only Author: Danny Edwards

1) Hypothesis Addressed in Lab:

Hypothesis: Both exhaled air at rest and exhaled air after intense exercise, will turn purple, Because of the presence of carbon dioxide. However, the sample of exhaled air after exercise will require more drops of ammonia than the sample of exhaled air without exercise, because more carbon dioxide is expelled during exercise than at rest.

Prediction: If the presence of carbon dioxide turns the cabbage solution purple, than the tubes with exhaled air after exercise and at rest will cause the solution to turn purple.

2) In the space below write a METHODS section for Part II (Cellular Respiration: Rest vs Exercise) only.

In this experiment we compared the effect that resting, and exercise has on cellular respiration. To test this, we observed how much carbon dioxide was produced. Because carbon dioxide is a byproduct of cellular respiration, it was used to indicate the level of cellular respiration that occurred. To start off, we prepared 4 tubes with 20 mL of cabbage extract that acted as an indicator for pH that changes color from blue (basic) to purple (acidic) in the presence of carbon dioxide. The four tubes were prepared under the conditions; no air, room air, air at rest, and air after exercising. To fill the test tubes with the appropriate air for each condition we used a bag apparatus to pump the air into the tubes, and “bubble” the air into the solution of cabbage extract. Tube #1 contained purely the cabbage extract and no air and served as a negative control. Tube #2 contained the cabbage extract and room air and served as a positive control. Tube #3 contained the cabbage extract and exhaled air without exercise. After bubbling the test tube with the bag apparatus, the solution turned from blue to purple indicating the presence of carbon dioxide. Lastly tube #4 contained cabbage extract and exhaled air immediately blown into the bag apparatus after 2 minutes of intense aerobic exercise. This tube also turned from blue to

purple indicating the presence of carbon dioxide. After the 4 test tubes have been treated with it’s corresponding air, drops of ammonia are added slowly to test tubes 2, 3, and 4, but not tube 1, as it didn’t contain carbon dioxide. Ammonia is basic, so its role in this experiment is to remove protons from the cabbage extract which increases the pH of the solution and changes the color of the solution from purple back to blue. Ammonia is added to the tubes until the solutions turn blue (original color of solution).

3) Attach your completed results for all sections.

4) Write a response to Review Question #1 from the lab manual (question text below). Write a follow-up hypothesis for this week’s lab. Imagine that you had access to any biological material you wanted (deep sea animals, desert plants, Olympic athletes, etc.). Think of a testable hypothesis you could address using the techniques and equipment from this week’s lab. Be creative…but make sure that your hypothesis follows the format described in the Lab Report Guide.

Hypothesis: Deep seas animals use gills to breathe instead of with lungs like in humans, but still preform cellular respiration, then as they perform more intense aerobic movements as opposed to staying still, they will produce more carbon dioxide.

5) Write a response to Review Question #4 from the lab manual (question text below). Which produces the most energy in the form of ATP? Explain your choice in as much detail as possible. a) Aerobic respiration b) Lactic acid fermentation c) Alcohol fermentation d) All of the above produce the same amount of ATP energy but through different chemical reactions e) None of the above produce ATP

a.) Aerobic respiration produces the most ATP. Although aerobic respiration happens more slowly than anaerobic respiration, it produces up to 38 ATP from only one molecule of glucose. Aerobic respiration occurs when oxygen is present, but in the absence of oxygen, only 2 ATP’s are produced. Without oxygen, organisms can only break a 6-carbon glucose into two 3-carbon pyruvate molecules, and ATP production stops after glycolysis. Both alcohol and lactic acid fermentation occur in the absence of oxygen and only produce 2 ATP. So, Aerobic respiration is far and away the most productive in producing large amounts of ATP, which can explain why aerobic organisms have come to dominate life on earth....