Cell Respiration in the Human Body
-Adapted from “Playing with Cell Respiration” Collaborative Learning Activity, McGraw Hill Education
The cell respiration pathways are complex and controlled. Substances may increase or decrease the effect of these pathways, and could have either helpful therapeutic or negative (even lethal!) consequences.
The compound DNP interferes with cellular respiration and was used as an effective weight loss treatment. Unfortunately, doctors found that “the treatment not only eliminated fat, but also the patients” (A New Look at Mechanisms in Bioenergetics, Academic Press, 1976, p. 155).
Substances that affect cell respiration may potentially be developed into ‘weight-loss’ drugs or ‘weight-gain’ drugs. Some of these substances are marketed as nutritional supplements that increase energy levels and enhance athletic performance.
A substance that decreases the production of ATP could be useful as a weight-loss drug.
Individuals taking such a drug (and eating the same amount as before) would need to convert more of the food consumed into ATP than before, having less to store in the body—and potentially burning fuel that was previously stored, both resulting in weight loss.
A substance that increases the production of ATP could be useful as a weight-gain drug.
Individuals (eating the same amount as before taking the drug) would need to burn less of the food consumed to get needed ATP levels, allowing more to be stored in the body—resulting in weight gain, or more energy available to the cell for activity.
Prompts:
- Briefly summarize the steps of aerobic cell respiration, beginning with glycolysis going through the Krebs cycle and ending with ATP synthesis in the mitochondria. Be sure to note the roles of electron carriers such as NAD+ and the proton gradient generated in the mitochondria.
- Now, for each of the substances below, consider the impact of each substance on cellular respiration.
- Substance A’s Effect: Prevents electrons from binding to NAD+.
- Determine whether this substance would result in weight gain or weight loss. Explain your reasoning.
- Substance B’s Effect: Increases the number of protons concentrated in the mitochondria intermembrane compartment
- Determine whether this substance would result in weight gain or weight loss. Explain your reasoning.
- The substances described above all interfere with aerobic respiration, requiring oxygen. When your cells run out of oxygen, such as your muscle cells during intense exercise, they can switch to lactic acid fermentation.
- Describe what lactic acid fermentation is, and compare the amount of energy produced during formation to the ATP yield of aerobic respiration.
- Carbohydrates, fats, proteins, and nucleic acids can all contribute to cell respiration through the various metabolic pathways in a cell.
- Which of these biomolecules is the most efficient at energy production? Explain your answer.
- What will your cells synthesize if more than enough ATP is currently being produced? (That is, how will your cells store this excess energy for later?)
Just make sure to always include references with citation, per APA formatting rules.
