Round Up: Investigating the Impact of Poison on Cellular Respiration

These past few weeks, my AP Bio class and I have been focusing on the cycles of life specifically the cycles of aerobic respiration. Now, trying to understand glycolysis, the citric acid cycle, and the electron transport chain can be pretty confusing and complicated because so many things are all happening at once. You know, it is crazy to think that our body can give us thousands of ATP molecules in a couple of seconds to help our bodies function!!! Anyway, we all worked on an activity on Cogentedu.com called Investigative Case: Cellular Respiration. I enjoyed this activity because it not only gave me a clearer understanding of all of the three major cycles but it also gave us me situation where I had to use my knowledge of the cycles and apply it to daily life.

The activity set up a scene where a man from the C.I.A. was poisoned, I was a toxicologist, and it was my duty to save this man’s life. The man was poisoned and experienced symptoms of dizziness and shortness of breath. To save him, I had to determine the specific cycle in cellular respiration that was being affected and then from there identify the specific poison that affected the person. The activity had us look at three pieces of data to help us determine the impact of the poison which are as follows: creation of pyruvate molecules. creation of NADH, and the amount of 1M proton concentration. The activity gave us control data of the amount of each category that was present in a functioning human body cell; the activity also gave us the changes in amounts of each category present in one of the poisoned man’s body’s cells. According to the data given, the man did not have a significant change in the production of pyruvate molecules, the amount of NADH molecules increased, and the amount of 1M proton concentration decreased. As a result, I believed that cyanide was the poison that affected him because cyanide impacts the electron transport chain by not allowing hydrogen molecules to bond to oxygen, become water, and then exit the electron transport chain. Since the data revealed that the amount of pyruvate molecules stayed relatively the same, I reasoned that cyanide does not impact glycolysis. However, the data also revealed that the amount of NADH produced had increased which makes sense because glycolysis continued to run and create more pyruvate molecules which the citric acid cycle took and made more NADH. And since the electron transport chain is inhibited by cyanide, the NADH electron carriers could not move on and donate electrons to the electron transport chain since the electron transport chain was already backed up with electrons. Lastly, the data revealed that 1M proton concentration decreased which makes sense since electrons are not passed down because if electrons are not passed down, then energy is not released which is used to pump protons from the matrix to the intermembrane space of the mitochondria and create a functioning proton gradient.

I was pretty happy to find out that my hypothesis was accurate because I felt like it meant that I went about the right away in understanding the information presented. I really enjoyed this activity and we are going to do another one hopefully on the process of photosynthesis so I am looking forward to that. :)

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