Electron Transport Chain Step by Step Explanation (Simplified)
Here, you will see the electron transport chain step by step explanation in an easy to understand jargon. Metabolic pathways such as this one is essential as it allows you to create and use ATP in order to perform work in your day to day life. You can think of the electron transport chain as the “last step” in the generation of ATP. This is not to say that your metabolic pathways work in such a sequential order, because they don’t. Instead, they work together harmoniously by depending on one another to either give or receive certain molecules.
The molecules that will be given or used will vary depending on which metabolic pathway you are looking at and in which direction you are looking at it ( the beginning or ending). For example, the metabolic pathway glycolysis starts off with glucose and ends in either two pyruvate molecules or two lactate molecules. Every metabolic pathway plays an integral part in the generation of ATP. Insofar as you are getting the proper nutrients you need to survive and maintain your metabolic demand, you can then expect to be utilizing the main metabolic pathways (glycolysis, glycogenolysis, citric acid cycle, etc.).
The electron transport chain is a very important metabolic pathway as it accepts many of the molecules from the other foregoing pathways. What the electron transport chain accepts specifically are the NADH’s and FADH’s that are produced from glycolysis, beta oxidation, and the citric acid cycle. NADH and FADH molecules are generated as by-products of the foregoing pathways. These molecules accumulate throughout specific regions of these pathways. These NADH’s and FADH’s are absolutely essential in the electron transport chain as they are needed to generate ATP. Below, I’ll go over the electron transport chain step by step explanation.
Electron transport chain step by step explanation
The electron transport chain has four specific areas here that we will get into. I’ll break down the electron transport chain step by step explanation by going over the four different complexes that reside within this metabolic pathway. Understanding these four different complexes will give you a much better insight on how the electron transport chain works in unison.
The electron transport chain occurs within the mitochondria. Essentially, mitochondria are very small organelles that are inside cells that deal with releasing energy from food, which is called cellular respiration. This is the reason that the mitochondria is referred to as being the powerhouse of the cell . A lot of energy can be generated from the mitochondria and you will understand more clearly how this is done by looking at the four complexes in the electron transport chain step by step explanation below.
In the electron transport chain, electrons move along a series of proteins to generate an expulsion type force to move hydrogen ions, or protons, across the mitochondrial membrane. The electrons begin their reactions in Complex I, continuing to Complex II, then to Complex III and cytochrome c via coenzyme Q, and then finally to Complex IV . Below are very brief and simplified descriptions of the four different complexes.
Complex I (electron transport chain step by step explanation)
Two electrons are removed from NADH and eventually make their way to lipid-soluble carrier called ubiquinone. Remember, the NADH that enters this complex comes from various other metabolic pathways, such as the citric acid cycle and glycolysis for instance.
Complex II (electron transport chain step by step explanation)
In this complex, more electrons are transferred. Remember, these electrons were cleaved off from the original NADH molecule that we first started off with in the beginning of complex I.
Complex III (electron transport chain step by step explanation)
In this complex, the Q-cycle contributes to the proton gradient by an asymmetric absorption/release of protons .
Complex IV (electron transport chain step by step explanation)
In the final complex of the electron transport chain, what you end up with are two molecules of water, as well as the creation of ATP.
As previously mentioned, the electron transport chain is an extremely effective pathway to generate ATP and energy. Essentially, any type of exercise is going to engage the electron transport chain. This is interesting to note due to the fact that not all metabolic pathways behave in such a manner. Such is the case with beta oxidation. This metabolic pathway will be utilized more so when you’re engaged in long distance or endurance exercise. On the opposite end of the spectrum, we have the phosphocreatine energy system. This metabolic pathway is utilized during the first 10-15 seconds of exercise. So, you would be using this pathway either in the beginning of exercise or if you’re doing anaerobic exercise. All in all, the electron transport chain step by step explanation provided in this article should hopefully give you a better understanding of how this metabolic pathway works not only by itself, but also alongside the many other metabolic pathways as well.References
- “Mitochondria – Cell Powerhouses.” Science Learn. https://www.sciencelearn.org.nz/resources/1839-mitochondria-cell-powerhouses
- “Electron Transport Chain Definition.” Biology Dictionary. https://biologydictionary.net/electron-transport-chain/
- “Electron Transport Chain.” Wikipedia. https://en.wikipedia.org/wiki/Electron_transport_chain