Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.
Oxidation & Reduction Reactions in the Metabolism: Process & Significance
ATP
Every minute of every day your body is building bones, repairing tissues, moving your muscles and performing all types of processes vital to your existence. All these actions require energy, and you get raw energy from the foods you eat, but there's a problem; you see, your body doesn't run on cheeseburger energy or broccoli power. So in order for the body to have energy, it must change the energy from the food into the form of energy your body likes to use, namely ATP, which stands for adenosine triphosphate. To produce ATP, your body cells use oxidation-reduction reactions, so let's take a look at how this works.
Redox Reactions
When we consider metabolism, which is the chemical processes of the body, oxidation and reduction reactions are best friends, meaning one cannot exist without the other. Because of this tight relationship, we often refer to them collectively as redox reactions, which is simply a combination of the terms reduction and oxidation reactions. And, like best human friends, these best chemical friends share things, namely electrons.
We know a few things about electrons. First of all, electrons always carry a negative charge. Secondly, electrons do not exist by themselves, instead they need to be attached to an atom. In fact, when you look at any atom, you see electrons circling around the outer shells, kind of like planets revolving around little solar systems. Third, when electrons move it's a form of energy. In fact, the electricity that you plug into in your home is really just the movement of electrically-charged particles, like electrons.
Like your home, your body generates energy through the movement of electrons, and this movement takes place within reactions that are called oxidation and reduction. Specifically, we see that oxidation reactions involve the loss of electrons, and reduction reactions involve the gain of electrons. You can recall how these reactions work by using the simple acronym OIL RIG. OIL stands for Oxidation Is Loss, meaning electrons are lost in this reaction, whereas RIG stands for Reduction Is Gain, meaning electrons are gained in reduction reactions.
Cellular Respiration
These reduction and oxidation reactions can be used to explain how we get energy from the foods we eat. Basically, electrons lost from the food molecules help to make ATP. For example, here we have a red food molecule that meets up with another molecule that we colored green:
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If we were to move an electron from the red food molecule to the green molecule, the red molecule would lose an electron and be oxidized - remember the acronym OIL tells us that Oxidation Is Loss. The green one is gaining an electron, and because we know from our acronym RIG that Reduction Is Gain, this molecule is being reduced. This movement of electrons produces energy along with a couple of byproducts.
This is a very basic look at redox reactions, but it's a good way to understand how energy is produced in cellular respiration, which is the process of oxidizing food molecules to make energy. In the case of cellular respiration, an electron is picked up from the Krebs cycle, also referred to as the citric acid cycle, which is a sequence of chemical reactions within the cell.
It might help you to think of the Krebs cycle as a product supplier, like Home Depot, who provides materials, in this case electrons. This electron is then trucked over to the electron transport chain (ETC), which is a series of compounds that pass electrons from one to another. This process produces energy in the form of ATP because every time an electron is transferred, energy is released. Therefore, you might want to think of the electron transport chain as the factory, where the product is used to create energy.
Lesson Summary
Let's review. We learned that your body needs to change the food you eat into a form of energy it can use, namely ATP. To do this it uses oxidation and reduction reactions. Specifically, we see that oxidation reactions involve the loss of electrons, and reduction reactions involve the gain of electrons, and we learned a handy acronym to help us remember this fact. The acronym OIL RIG tells us that Oxidation Is Loss, whereas RIG stands for Reduction Is Gain.
These reactions, which collectively are referred to as redox reactions, occur in cellular respiration, which is the process of oxidizing food molecules to make energy. In cellular respiration, we see that electrons are picked up from the Krebs cycle and carried to the electron transport chain (ETC). As the electrons are transferred, energy is released.
Learning Outcomes
After this lesson, you'll be able to:
- Define oxidation and reduction reactions as well as cellular respiration
- Identify an acronym to remember the movement of electrons in redox reactions
- Summarize how redox reactions function in cellular respiration
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