Module 7

MODULE 7

Chemical Reactions and Me Activity 

Chemical reaction net equation:

4e- + O2 + 4 H+ --> 2 H2O

Introduction

The most interesting chemical reaction discussed in Module 7 in my opinion was the DIGESTIVE PROCESS.  The citric acid cycle and electron transport chain (and ATP synthase) are necessary for the synthesis of ATP, the source of energy in our bodies.  This is why I picked this reaction because I believe it is most important for humans.  This reaction releases reactive oxygen species; however, it is so important that our bodies do it anyways!  We need energy for survival and these steps allow us to take the food we eat and convert it to energy (in the form of ATP) so our body can perform work.  An interesting fact about this is that when someone gets the death penalty, the drug actually stops a vital pathway in this system and shuts down the ability for our body to form a proton gradient, which drives ATP synthesis and forms ATP from ADP and Pi.  Without ATP, our body cannot perform necessary functions and we die.  This is a vital process in our bodies.  It's interesting to me because our bodies are so efficient and the only reason they would do something that releases reactive oxygen species (ROS) is because the reaction is more favorable in another way (aka generating ATP from food for our survival). 

Now that we understand more about this pathway, let's take a look at how this pathway releases ROS…

The reason we are able to generate this proton gradient is because we are trying to reduce O2 to water.  Electron flow through the Electron Transport Chain until they are able to reduce oxygen to water.  During this process, electrons travel down the chain to reduce O2.  When O2 gets reduced, it grabs 2 protons to form H2O.  Without this need to reduce water, the electrons would not travel down this pathway and we would not be able to generate any ATP. It is literally the reason we breathe oxygen.

The problem, however, is that this pathway actually releases 2% ROS, reactive oxidative species.  These can be good to destroy invading bacteria and viruses; however, they can often cause a lot of damage, including inflammation. One interesting problem that ROS can cause is making our lipid bilayer membranes more stiff, which is a HUGE problem! We need those bilayers to be fluid!

GOOD NEWS! Antioxidants naturally found in your body (and taken in externally from food) can help to counteract this oxidative stress so our bodies can continue this vital pathway!