Energy Consumption during Exercise Lab Answers

Aerobic exercise and fitness can be contrasted with anaerobic exercise, of which strength training and weight training are the most salient examples. The two types of exercise differ by the duration and intensity of muscular contractions involved, as well as by how energy is generated within the muscle.

Initially, during aerobic exercise, glycogen is broken down to produce glucose, which is then broken down using oxygen to generate energy. Anaerobic exercise, in contrast, refers to the initial phase of the exercise, or to any short burst of intense exertion, in which the glycogen or sugar is consumed without oxygen, and is a far less efficient process.

This is why individuals are taught to constantly breathe during weight lifting, otherwise, we can perform at the same rate, or with the same intensity.

Purpose

To compare power during aerobic and anaerobic exercise and how much glucose does exercise consume?

Hypothesis: As a group predict that aerobic exercise will consume more glucose because of oxidation phosphorylation which produces more ATP. Thus more reps will be done under this condition.

Or in other words stage, 1 of the lab will have more reps than stage 2 because there is more energy available. During aerobic respiration the continuous breakdown of sugar will allow more activity to be done versus anaerobic respiration which will just be able to use the energy it currently has, it will not be able to create more.

Materials: -dumbbell or mass (2.5 kg or 80% of the heaviest mass you can life once)

–   meter stick

Procedure

• Place the dumbbell on a flat surface such as a desk
• Grip the dumbbell with your arm and put it flat on the desk your arm. Thus making the dumbbell rest on the desk.
• Place a meter stick on the edge of the desk. Have your partner hold the meter stick straight up.
• Lift the dumbbell by bending your arm at the elbow 1 time so that your partner can measure the vertical distance the dumbbell covers when it reaches its highest point.
• While you perform step 6, your partner should record the time elapsed at the end of stage 1(which is aerobic exercise when you feel no pain or discomfort lifting the dumbbells) and again stage 2 (which is anaerobic exercise in which your muscles feel discomfort) and count the number of lifts in each of the stages. Each lift has to be a full lift which means it meets the same vertical distance each time.
• Remember that you have to keep doing stage one until you start feeling sore, tell your partner at this point to record the lifts.  In stage 2 just keep counting lifts until you can’t do anymore.

Observations

c) Dumbbell mass = 9.1kg (20 pounds)

d) vertical distance dumbbell moves = 0.35m (35cm)

e) time elapsed by  the end of stage 1 = 115 seconds

f) Number of lifts in stage 1 = 42 lifts

g) total time elapsed by the end of stage 2 = 418 seconds per stage 2 time 303 seconds

h) Number of lifts in stage 2 = 108 -> total lifts = 150

Calculations

1)i) Force = mass X acceleration

= 9.1kg X 9.81m/s^2

= 89.271kgm/s^2

2 j) Energy Gravitational = mass X acceleration X height (distance)

= 9.1kg X 9.81m/s^2 X 0.35m

= 31.24485J

3) k) Work = Eg

= 31.24485J / lift

4) Stage 1

W (total) = W J/lift x n lifts

W (total) = 31.24485 x 42

W (total) = 1,312.2837 J

Stage 2

W (total) = W J/lift x n lifts

W (total) = 31.24485 x 108

W (total) = 3,374.4438 J

5) n) power during stage 1 = 1,312.283J/ 115 seconds

P= 11.4 W

0) power during stage 2 = 3,374.4438 J/ 303 seconds

P= 11.14 W

6)      p) moles of ATP used during exercise (stage 1 and 2)

=   13390.65 J x (1kJ/1000J) x (1 mol of ATP/2870 KJ)

= 4.46 x 10^-3 mol of ATP

7) q) moles of glucose used

=    4.46 x 10^-3 mol of ATP x 1 mol glucose/30 mol ATP

=    1.48 x 10^-4 mol glucose

8)      r) 1.4866 x 10^-4  mol of glucose used x  (1 mol sucrose/ 2 mol glucose)

=    7.43 x 10^-5  mol of sucrose

9)       (s)  7.43 x 10^-5 mol sucrose used x 342g/mol

=   2.54 x 10^-2 g sucrose

10)         (t)   2.54 x 10^-2 g sucrose x ( 1 teaspoon sugar/ 4 g sucrose)

=        6.35 x 10^-3 teaspoons of table sugar

Analysis

After doing this lab there are several things that are apparent. First, we had an opportunity to observe both aerobic and anaerobic exercise. In our hypothesis we predicted that more ATP would be produced because of oxidative phosphorylation which yields in more ATP then it’s counterpart substrate level phosphorylation which is done without oxygen.

We predicted more reps would be done in stage 1 (aerobic respiration) versus stage 2 (anaerobic respiration). Since we learned earlier that oxygen is a vital part of the electron transport chain and is the electronegative element that moves those crucial electrons across the membrane. Without the presence of oxygen, there would be no hydrogen ions being pumped across the membrane or enough to create that electrochemical gradient which in the long run goes to ATP synthase, in a nutshell, the process that produces ATP.

Therefore, the only logical assumption would be to predict that more reps would be performed in stage 1 because; oxygen is still present during this stage. With anaerobic respiration, we are only doing Glycolysis. Where ATP is produced through, however, keep in mind only 2 ATP are produced substrate phosphorylation. Unlike its counterpart oxidative phosphorylation which in the electron transport chain can have a theoretical yield of 32 ATP.

So why this long explanation of substrate level and oxidative phosphorylation? During strenuous exercise, muscle cells require glucose faster than oxygen can be supplied. This is important because we know during exercise oxygen is being used to help the muscles do the work of lifting the dumbbell.  Under such conditions, oxidative respiration slows down and lactate fermentation begins.

This evidently is noticed when there is pain or some discomfort felt doing the exercise, which in this lab has been named stage 2. In lactate fermentation what ends up happening is the NADH produced in Glycolysis transfers its hydrogen atoms to Pyruvate in the cytoplasm of a cell, which produces NAD+ once again, and thus Glycolysis continues. As we know Glycolysis only produces 2 ATP as mentioned earlier. This implies if Glycolysis keeps occurring the ATP yield is less than that of oxidative phosphorylation,

When the strenuous exercise comes to a halt the lactate molecules in the muscles cells, are transported through the blood stream to the liver. Once there lactate goes through a redox reaction and is oxidized back into Pyruvate which of course goes to the Kreb cycle and can once again oxidative phosphorylation can occur again.

So when we look at this lab we noticed first that the discomfort that the participant experienced was lactate fermentation. Then we looked at our results and there was a difference. To all our knowledge and further research we were expecting the power to be down in stage two.

(Once again because not enough ATP are being produced, since Glycolysis kept occurring which yields, once again as repetitive as this may sound, only 2 ATP and which is much less than that off oxidative phosphorylation which was occurring when The participant was meeting the demand of glucose and oxygen to break it down.)

However, according to our results, the participant’s work level was up! He performed more curls (reps) with the dumbbell in stage 2 than he had in stage 1. Thus after some discussion, the participant admitted that he had casually said, “I feel the burn”, when he really didn’t because the guys around him thought he was showboating and being a big shot by saying he felt no burn at 42 lifts.

Thus that is why he went on to perform 108 more lifts in stage 2. After trying to recall when he actually felt the burn (now we know that this burn is actually the lactic acid build-up) he approximated that it was at about 125 reps thus, this would total his reps in stage 2 to a mere 25.

This is only 1/5 of his stage 1 reps. These results would make a lot more sense according to all our research and prior knowledge from this unit about substrate level and oxidative level phosphorylation. Thus there was some human error during the lab that must be taken into account for!

In the textbook it states: do you feel hot after lifting the dumbbell? We came to the conclusion this is due to the fact that this is an exorgenic reactions and energy is released as heat to some extent.

Conclusion

We predicted that the aerobic would produce more ATP because of oxidative phosphorylation and thus due to this higher level of ATP present, more reps would be performed in stage 1 (aerobic) versus stage 2 (anaerobic) and we were correct. This is evident through the difference in power in stage 1 and 2 via work done (number of times the dumbbell was lifted). Power is greater if there is more ATP being produced thus more energy for a greater power. More reps done to the presence of oxygen in stage 1 which helps in oxidative respiration and the creation of more ATP! MORE ATP = MORE REPS!

Reference:

http://www.purchon.com/biology/aerobic.htm

http://biology.clc.uc.edu/Courses/Bio104/cellresp.htm