In order to move and process internally, humans must generate and use energy. How we do that, relies on a number of metabolic reactions, that rely upon the use of a molecule known as ATP. ATP stands for adenosine triphosphate and is arguably the most import molecule in the human body and is referred to as the energy currency for life, as it’s the primary source of fuel for every cell within the human body.
ATP is composed of one adenosine molecule and three phosphate groups. The adenosine molecule is a combination of adenine (a nitrogen-containing base) and ribose (a five carbon sugar). Attached to this adenosine molecule are three high energy bonds or inorganic phosphate (Pi) groups, bonded together in sequence. As explained in my previous blog (What Is Energy), ATP is able to provide cellular energy, when at least one of the three phosphate bonds detach, allowing energy to flow out into a cell. (Link to blog: http://www.jfpersonalfitness.com/what-is-energy-atp/ )
In order for the ATP molecule to provide fuel for cells and recharge them once they are spent, it must have a flow of energy that provides a source of replenishment for the molecule. This comes from the breakdown of food, more specifically the macronutrient groups protein, fat and carbohydrates. The energy value of each macro group is expressed in calories, protein has four calories per gram (g), carbohydrates also have four calories per gram and fat is the more calorie dense macro with 9 calories per gram.
In order for the ATP cell to use the chemical energy the macronutrients provide, it must use enzymes to break them down and then convert them into a bioavailable form. Protein is broken down in amino acids, carbohydrates into sugars/glucose and fats are converted to fatty acids or glycerol. The understanding of the terminology used for the reactions in our bodies metabolic functions isn’t a necessary requirement to know for the general public. However, to truly develop an understanding of energy, its production and subsequent contribution to optimal training and nutrition, knowing certain metabolic processes will guide you to better choices.
The word metabolism/metabolic is thrown around a lot, the mechanisms that make up our “metabolism” are briefly explained in this paragraph. The breakdown of larger molecules to smaller ones, is referred to as catabolism/catabolic, for example breaking a protein molecule down into amino acids etc. The creation/synthesis of larger molecules from smaller ones, is known as anabolism/anabolic, for example the formation of a protein molecule from amino acids. Exergonic reactions are energy releasing processes, for example the process of using an ATP molecule for cellular fuel. Lastly, you have Endergonic reactions, which require energy to function, such as the cell that requires energy from the ATP molecule. Catabolism, anabolism, exergonic and endergonic reactions collectively total, what is referred to as our metabolism.
So hopefully, the information above was digestible and helped you understand how ATP essentially gets its fuel. ATP helps transfer energy from the energy releasing reactions, to the energy requiring sources. Without ATP we wouldn’t function and if you want to optimise your training and nutritional choices, reading on this topic in further detail will help you greatly.