Spotlight On: Mitochondria

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You may remember learning about mitochondria, the “powerhouse of the cell” in science class. Mitochondria earned this nickname because of their ability to maintain the supply of a chemical called ATP that is our primary source of energy. Mitochondria help with almost every reaction in our body that requires energy, from contracting our muscles, to transmitting signals in our nervous system. Because humans have a lot of mitochondria, we’re capable of impressive feats of ultra-endurance and complex cognitive function.

Fat and sugar molecules from the foods we eat break down and release energy that, through a series of complex chemical reactions, generates the ATP that our body needs. There are many steps and energy conversions along the way, but the simplified chemical reaction is similar to the combustion reactions that power our cars and planes. Mitochondria, however, are much more efficient.

Mitochondria also contain their own DNA. Unlike the DNA we inherit from both parents (called nuclear DNA) that is arranged in long strands, we get our mitochondrial DNA only from our mothers. Mitochondrial DNA is arranged in a circular pattern commonly seen in bacteria. Scientists believe that mitochondria were once separate bacterial organisms that were enclosed by other cells, creating a symbiotic relationship that has lasted over 1 billion years.

Because of their powerhouse role, damage to mitochondria can be harmful and even deadly to our cells. Mutations can occur in mitochondrial DNA, which changes the code used to create proteins in our body. These mutations can be passed along at birth or may happen as we age. Dysfunctional mitochondria can affect aging and may be a cause for developing conditions such as type 2 diabetes and cancer.

Luckily, we can control what happens to our mitochondria. Exercise and proper nutrition can help us build more, and better quality, mitochondria that keeps our “powerhouse” running at full force.

Ravi Kumar is a PhD candidate in exercise physiology at the University of Florida. He is an avid runner and sports enthusiast, and his research interests include skeletal muscle and mitochondrial biology and how these systems adapt to exercise, aging and chronic heart failure.

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