ENERGIZE YOURSELF!
This post is meant to be the first in a series of posts dedicated to the metabolic pathways that create ATP or its equivalents within the cells. We will focus on muscle cells, since they are a "preferred client" of sorts, especially during exercise, and evermore during maximal exercise. Each metabolic pathway is a set of bio-chemical reactions that occur in a specific order, resulting in a certain result with one or more metabolic implications.
While we distinct three (3) ATP producing metabolic pathways in the cell, these three metabolic pathways utilize five (5) different processes that result in ATP creation. Since the third metabolic pathway include three processes to create ATP, while the first two only offer one ATP producing process each, it adds-up to a total of five ATP producing processes within the cell.
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General analysis of these three metabolic pathways, leads us to the following knowledge and conclusions:
Two out of the three metabolic pathways are anaerobic (they create energy without oxygen required as part of the process); The third is aerobic (requires oxygen in order to create energy)
One of the metabolic pathways creates lactic acid in addition to the creation of ATP
The two anaerobic metabolic pathways occur in the cytoplasm of the cell; The third occurs within the mitochondria (plural) of the cell
The two anaerobic metabolic pathways create energy the fastest, yet the least energy in total (per whole cycle metabolic pathway work)
All three pathways always work parallel to each other, yet not necessarily to the same extent (not the same percentage of the overall energy cost of the activity analyzed)
The main question is which metabolic pathway is the most dominant? - meaning that it is producing the greatest percentage of energy of all three
While all three metabolic pathways work together to supply 100% of the required energy for a given activity or exercise, the order of dominancy (who will produced the greatest percentage) is determined by the circumstances, and which metabolic pathways has the greatest and/or the most advantages to offer under the specific circumstances.
None of the metabolic pathways is perfect; Thus, it is a matter of weighing in the advantages vs disadvantages of using each metabolic pathways under the current certain circumstances. The greatest advantages of anaerobic energy production is how fast the energy is produced and available for use. This advantage is the result of not needing to breath, circulate, extract, and use oxygen as part of the energy production process. The main disadvantage of both anaerobic metabolic pathways is that they create lesser energy compared to aerobic metabolism of the same substrate. Another possible, yet very influential disadvantage of one out of the two aerobic metabolic pathways is the increase in the acidity of the cell.
The winner advantage of the aerobic metabolic pathways is the amount of energy produced from the same substrate (at least 12 times more, and usually more, much more). Although not significant, aerobic energy production create a bit of water molecules (termed metabolic water) which insignificantly hydrates the cells (better that than nothing though). Another big advantage of the aerobic metabolic pathways is the fact that it is more diverse and flexible in the substrates that can use to create energy. The greatest disadvantage of aerobic energy production is the length of time it takes due to the need for oxygen. This disadvantage is "felt" even more, the bigger the substrate broken down (catabolized) such as fat and proteins.
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Please be on the lookout for other posts regarding the metabolic pathways, for more in-depth knowledge and insights!
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