Tri-2, Wk12, Day 118 - Friday ATP

I'll focus a little on ATP today. ATP stands for adenosine triphosphate. Notice the prefix "tri" before the word phosphate which indicates we have three phosphate atoms in ATP. When ATP is broken down it releases energy which I believe is along the order of -31 kJ/mol. Those units are kilojoules per mole. The negative sign indicates an exothermic reaction in which energy is released. There are many words we've encountered which make use of the 'ex' prefix. The most common word we all know is the word 'exit' which has the ex prefix. We also have the word exogenous which refers to something coming from outside of a system.

When ATP is broken down it loses a phosphate and goes from a tri-phosphate to a di-phosphate and is then known as ADP (adenosine diphosphate)

What I've been curious about is that ATP is kind of referred to as an energy source, the high octane fuel of the human body but, when it comes to muscle contraction, a primary role of ATP is to allow our muscles to relax after contraction. When we die, ATP production stops and muscles will stay in a contracted position which is referred to as rigamortis.

We also have the prefix endo which is used in endothermic and describes a process in which energy is consumed. Endogenous means coming from withing. In biochemistry we'll refer to taking resources in via our diet as exogenous while those things being made inside our body as endogenous. Endo is also used to describe many of the tissues in our bodies which are closest to the innermost portion of an organ.