Understanding the Process of Cellular Respiration
Published by Dr. Venn-Watson
Dr. Eric Venn-Watson’s Highlights
You know that cells are the foundation of our bodies, making up tissues that make up organs that make up the rest of us. However, you might not have considered how our cells do it all. How do tiny, microscopic organisms filled with even tinier organelles produce energy and keep us running?
The process is called cellular respiration. When we consume foods like carbohydrates, our cells use this process of chemical reactions to transform those simple carbs into high-energy molecules that power the cell, and ultimately, our entire bodies.
Together, we’ll take a closer look at how cellular respiration happens, where it happens, and what happens to our cells’ power plants as we age. We’ll also discuss how a newly discovered essential fatty acid can help support the mitochondria in our cells, and help us make aging our ally.
What Is Cellular Respiration?
Cellular respiration is the process by which living cells convert a molecule of glucose into energy. Our cells get glucose from our bloodstream. The foods we eat contain compounds that are broken down into glucose and delivered to the cell for use.
Glucose that gets delivered to the cell starts a chain reaction of chemical events that result in the outcome of powering the cell. The energy created in the cell powers cellular activity. Cellular activity powers every process in your body, i.e. cellular respiration is pretty important.
Where Does Cellular Respiration Take Place?
There are two different types of cellular respiration. Aerobic respiration requires oxygen, and anaerobic respiration does not require oxygen. Human cells (which are eukaryotic cells) only use aerobic respiration (with oxygen). Most prokaryotic organisms use both aerobic and anaerobic respiration, switching between the two depending on their environment and what resources are available.
The human cell respiration process takes place within a tiny organelle inside the cell called the mitochondrion. This organ is unique, in that it has its own cell membrane. In fact, it has two — a larger, outer membrane, and a smaller, inner mitochondrial membrane. That makes aerobic respiration a little more complex than anaerobic respiration, but aerobic respiration still generally produces more energy than anaerobic.
How Aerobic Respiration Works in the Human Cell
When you have the energy you need to sustain yourself for a three-mile run, you don’t wonder how the energy in your muscles came to be, you only know it is there. Let’s look at the nuts and bolts of how that energy came into existence.
We can break down the process into four stages of cellular respiration.
Glycolysis is the first step in cellular respiration. When you eat food it is broken down into small, usable molecule packets that are delivered to your cells for their use. Glucose molecules are sent to your cells to begin the respiration process.
Glycolysis is the first step in ATP production. During the first part of glycolysis, the glucose is broken down into adenosine triphosphate, or “ATP” in the cytoplasm of the cell. This is called ATP synthesis. This part of glycolysis also produces pyruvate and molecules of NADH.
Remember, for cellular respiration to occur in a human cell, we need it to happen in the mitochondria. Now that the glucose has been broken down into a form of ATP, pyruvate, and NADH, we can look at how these molecules move to the mitochondria, specifically to the mitochondrial matrix, the innermost part of the mitochondria.
2. Pyruvate Oxidation
Pyruvate oxidation connects glycolysis to the rest of the cellular respiration process, but no energy is actually produced during this step.
Molecules of pyruvate travel to the mitochondrial matrix, where it is then converted to acetyl CoA. This acetyl CoA is attached to coenzyme A, an organically occurring enzyme that helps form acetyl CoA.
Although we haven’t produced any usable energy in this step, we’ve produced the molecules necessary for the third part of cellular respiration, the citric acid cycle.
3. Citric Acid Cycle
Also known as the Krebs Cycle, this portion of cellular respiration also takes place in the matrix of the mitochondria. This series of reactions uses the CoA produced in the pyruvate oxidation process to NADH, FADH2, carbon dioxide, and another ATP molecule.
Ultimately, the purpose of the citric acid cycle is to produce ATP, NADH, and FADH2. These three chemical compounds will drive the creation of energy in the fourth and final step of cellular respiration. While there are numerous steps in the Krebs Cycle, for our purposes, we’ll focus on the product of the cycle, which is now ready for the electron transport chain.
4. Electron Transport Chain
During the final stage of cellular respiration, the compounds that have been created within the mitochondria of the cell will be pulled out of the cell membrane and converted into mass amounts of ATP, which the cell will then use for energy. This stage also produces water.
Enzymes in the membrane of the mitochondria extract the NADH and FADH2 from the mitochondria and pull them across an electrochemical gradient in a process known as oxidative phosphorylation. This is a proton gradient where energy is converted in large amounts.
If you guessed that this process requires the presence of oxygen, you’re absolutely right.
Oxygen and phosphate help carry the NADH, FADH2, and low-energy adenosine diphosphate (ADP) molecules into the cytoplasm of the cell and convert them to ATP, which is usable for the cell as energy.
The Products of Cellular Respiration
The products of the final stage of cellular respiration are about 30+ molecules of ATP, carbon dioxide, and hydrogen ions (water). That’s pretty impressive considering the reactants used were simple sugar and oxygen at the very beginning of the process.
This process happens quickly in our cells, without us ever thinking about it. But this is the power that drives our bodies to perform and function properly. What happens to the process, then, when our cells age?
What Happens With Cellular Respiration As We Age?
It’s no secret that we can feel tired and sluggish as we age, but is it really something we have to accept, or is there a way to proactively care for our cells?
As our cells age, they experience lowered oxidative capacity. This means their ability to use available oxygen in the cellular respiration process decreases. Decreased oxidative capacity means decreased ATP production.
Aging cells also experience lowered mitochondrial function. For eukaryotes, that means less and less energy-producing capability. When our cells can’t create enough energy, they can’t perform the functions necessary to keep us healthy and energized. Our cells’ metabolic pathways begin to change, and we experience age-related illness.
Supporting Cellular Health
Aside from eating a balanced diet and getting enough exercise, how can you actually care for your cells and protect your cellular health from decline? The answer? We found it in a surprising place: dolphins.
How Dolphins Help Us Understand Age-Related Illness
Dolphins are a lot like humans, and they also suffer from illnesses as they age. While studying two populations of dolphins, veterinary epidemiologist Dr. Stephanie Venn-Watson discovered that some geriatric dolphins had less age-related illnesses than others.
Dr. Venn-Watson found that higher circulating levels of a particular fatty acid (that we now know is essential - meaning our bodies don’t make enough of it and therefore, we must get adequate amounts from our diet to stay healthy) were responsible for many of the health benefits that were seen in the healthiest dolphins. She went further, looking into the health benefits of this molecule in human populations and three years later, published her findings in Nature's Scientific Reports in 2020.
What C15:0 Does
C15:0, or pentadecanoic acid for short, is an odd-chain, saturated fatty acid that research supports as the first essential fatty acid to have been discovered since the omegas more than 90 years ago.
C15:0 directly helps our cells in two important ways:*
- Strengthens cell membranes. As we age, our cell membranes weaken, making them susceptible to external stressors. C15:0 integrates into cell membranes, fortifying them and keeping them strong so the organelles inside can keep doing their thing without threat from outside aggressors.
- Increases mitochondrial function. Aging cells can mean sluggish mitochondria. C15:0 has been shown to improve mitochondrial function by up to 45%, enabling your cells to keep making the energy your body needs, ATP and all.
That’s amazing news for aging cells, so how do we get this fatty acid into our bodies? Well, C15:0 is mostly found in trace amounts in whole-fat dairy products and a few plants. Unfortunately, as a society, we’ve decreased our intake of many of these sources of this essential fatty acid, and have even shifted to plant-based milks that are completely void of C15:0. Even if we made a move back toward dairy, consuming whole-fat milk products would mean consuming the extra calories, sugars, and bad fats that come with it, which we don’t want or need.
Thankfully, we’ve come up with a solution: fatty15, the pure, vegan-friendly, award winning, single-calorie daily supplement that can give you back the C15:0 your body needs.
Fatty15: Healthy Aging Starts Here
Cellular respiration is how our cells produce energy to carry out their functions and power our bodies. When we age, the place where our cells make their energy, the mitochondria, begin to become sluggish.
Kickstart your mitochondria and support your cellular health with the only supplement that contains the pure, vegan-friendly version of C15:0, fatty15. Just one capsule per day can support your cellular health and give your cells a fighting chance, resulting in a healthier feeling you*
Eric Venn-Watson M.D.
Senior Scientist, Co-Founder
Eric is a physician, U.S. Navy veteran, and Co-founder and COO of Seraphina Therapeutics. Eric served over 25 years as a Navy and Marine Corps physician, working with the special forces community to improve their health and fitness. Seraphina Therapeutics is a health and wellness company dedicated to advancing global health through the discovery of essential fatty acids and micronutrient therapeutics.
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