Thursday, October 16, 2008

Metabolism Part I: Fuel Sources

We're learning about metabolism this week. Personally, I find the subject interesting because understanding metabolism can put a lot of fad diets and workout myths to rest. I've looked up information regarding these workout myths before, but never found a single source of information that discussed them.

Remember, I'm learning about metabolism for the first time right now and we are learning just a BRIEF overview of metabolism right now. That is to say, the concepts I am describing in the next few posts have been simplified and gloss over the true complexity of our metabolism.

This first post will describe fuel sources. Our bodies need energy. In our bodies, energy is ATP, a molecule that is used to power many cellular reactions. ATP can come from carbohydrates, proteins, and fats.

Sugars are carbohydrates. There are several different kinds of sugar, but the main one that is discussed with regards to metabolism is glucose. The process of turning sugars into ATP is called glycolysis. Glycolysis can occur with or without oxygen. However, more ATP are generated when glycolysis occurs with oxygen because one of the products of glycolysis can go onto generate further ATP when oxygen is present.

Fats are made up of fatty acids and a molecule called glycerol. Glycerol can be converted to glucose and make ATP through glycolysis. Fatty acids can make ATP through a different process called beta oxidation. Beta oxidation requires oxygen.

We generally do not want our bodies to use protein as a fuel source because proteins have many other tasks in our body. Proteins are responsible for cell stability, building muscles, and many other tasks. However, some proteins can be transformed into glucose and generate energy through glycolysis. Other proteins can generate ATP through the oxygen dependent path discussed with carbohydrates.

Next, I'll discuss hormones.

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