Aerobic Cellular Respiration Humans, and all animals, use adenosine triphosphate (ATP) as the main source of energy in cells. The authors of Biological Science 5th Edition state that “In general, a cell contains only enough ATP [adenosine triphosphate] to last 30 seconds to a few minutes.” It's like this “Because it has such high potential energy, ATP is unstable and is not stored.” They also state that “In an average second, a typical cell in your body uses an average of 10 million ATP molecules and synthesizes [produces] just as many.” There are trillions of cells in the human body. The average human body uses and produces 10,000,000,000,000,000 ATP molecules every second. In one minute the human body uses 600,000,000,000,000,000 ATP molecules. In one day the human body uses 864,000,000,000,000,000,000 ATP molecules. In a year this is equivalent to 365.25 days; the average human body uses and produces a huge amount, 315,576,000,000,000,000,000,000 ATP molecules. For this example, one mile is equivalent to one molecule of ATP. Light travels at approximately 186,000 miles/sec. It would take light about 53,763,440,860 years to travel that many miles. The huge amount of ATP produced in people's cells is astonishing! This essay will go some way to explaining the main way of producing all those ATP molecules in aerobic organisms, aerobic cellular respiration. There are four phases that occur in aerobic cellular respiration and they are: 1. Glycolysis; 2. Pyruvate processing; 3. Citric acid cycle; 4. Electron transport and oxidative phosphorylation (Allison, L.A., Black, M., Podgoroski, G., Quillin, K., Monroe, J., Taylor E. 2014).1. Glycolysis is a multi-step process. The authors of the fifth edition of Biological Science stated that ... half of the article ... in human cells (multicellular organisms) switching from aerobic respiration to anaerobic respiration. This causes less energy to be produced per glucose molecule (Baskin, SI et al. 2014), (“Environmental”. ND) (Allison, LA et al. 2014). The less energy produced causes cells to die from lack of energy, and once enough cells die, multicellular organisms (humans) die. References Baskin, S.I., Kelly, J.B., Maliner, B.I., Rockwood, G.A., Zoltani C.K. (2013). "Chapter 11 Cyanide Poisoning". Retrieved from https://www.hsdl.org/?view&did=18123“Environmental and health effects”. (ND). Retrieved from http://www.cyanidecode.org/cyanide-facts/environmental-health-effectsAllison, L.A., Black, M., Podgoroski, G., Quillin, K., Monroe, J., Taylor E. (2014) . Biological Sciences, Fifth Edition. Glenview, IL. Pearson