Cellular Respiration
BIO 120L
Dr. Alba Chavez/Shivani Patel
March 27, 2022
Introduction
Objectives: Study cellular respiration by calculating and comparing the breathing rate, heart rate and
carbon dioxide production before and after exercise. In this way, we can determine what impact
exercise will have on cellular respiration.
Hypothesis: Cellular respiration increases as you increase you exercise intensity. Human body will
increase the breathing rate, heart rate and carbon dioxide production during exercise in order to
increase the delivery of oxygen.
Materials
Timer, Graduated cylinder, Phenol red solution, Beaker, Straw, Two people
Methods
Part A(Resting):
Measuring Breathing Rate: 1. Count the number of breaths taken in one minute. 2. Repeat steps
1. 3. Record and average two experimental data.
Measuring Heart Rate: 1. Calculate the heartbeat in 30 seconds and multiply by two. 2. Repeat
steps 1. 3. Record and average two experimental data.
Measuring Carbon Dioxide Production: 1. Measure 20 ml of phenol red solution and pour it
into a beaker. 2. Exhale into the solution with a straw. 3. Time how long it takes the solution turns
yellow. 4. Wash the beaker and repeat steps 1-4. 5. Record and average two experimental data.
Part B(Exercise):
1. Exercise for 1 minute.
2. Partner prepares 20 ml phenol red solution.
3. After exercise, immediately exhale into the solution with a straw. Record the time for
solution turns yellow.
4. Count the number of breaths taken and heart rate like in part A.
5. Wash the beaker and exercise for 2 minutes.
6. Repeat steps 3-4.
7. Record these values.
Data and Results
Resting
Breathing Rate
Exercise
First Measure
Second Measure
1 Minute
2 minutes
14
13
16
20
44/88
41/82
63/126
75/150
19
17.30
13
9
(Number of breaths)
Heart Rate
(Number of beats)
Carbon Dioxide Production
(Time for solution turns yellow)
Conclusion
The experimental results showed that exercise increases breathing rate, heart rate and
carbon dioxide production. Moreover, as the exercise time increased, the breathing rate, heart
rate and carbon dioxide production also increased. This confirms the hypothesis at the
beginning of the report that cellular respiration increases as the intensity of your exercise
increases.
Limitations and Future Directions：
1. There are no professional instruments to measure the heartbeat, which may lead to a
slight error in the measurement results.
2. Since it is based on visual observation, it is difficult to determine the exact time when
the phenol red solution turns yellow. This error time is in the range of 1-2 seconds.
3. The breathing rate is not constant. Deep breathing will reduce the number of breaths.
Discussion
How does microgravity affect mitochondria and cell respiration?
Microgravity has a significant impact on mitochondrial function, which can lead to
significant adaptive changes in mitochondria or apoptotic responses of cells. These effects
can make the mitochondria smaller in size, which can reduce oxygen consumption and the
respiratory capacity of the mitochondria.
Reference Page
Nguyen, H.P., Tran, P.H., Kim, KS. et al. The effects of real and simulated microgravity on
cellular mitochondrial function. npj Microgravity 7, 44 (2021).
https://doi.org/10.1038/s41526-021-00171-7
Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., Orr, R. B., & Campbell, N. A.
(2021). Campbell Biology. Pearson.
Stutte, G.W., Monje, O., Hatfield, R.D. et al. Microgravity effects on leaf morphology, cell
structure, carbon metabolism and mRNA expression of dwarf wheat. Planta 224, 1038–1049
(2006). https://doi-org.ezproxy.libproxy.db.erau.edu/10.1007/s00425-006-0290-4