Coronary Artery Disease and Oxidative Stress

Abstract

O2 arose on Earth in about 3.8 x 109 years ago due to the photosynthetic process in cyanobacteria hydrolyzed water. But it was only about 2.5 x 109 years ago that its levels rose to significant amounts. The increase in atmospheric concentrations of O2 led to a great selective event, the first great mass extinction, due to stress on organisms that did not adapt to the new conditions. It also helped in the conquest of the land with the formation of O3 (ozone) in the stratosphere, which filters the most harmful of the ultraviolet radiation (UV-C). In addition, using the O2 as a substrate, the organisms generated much more energy (about 32 times more) but, in doing so, they started to generate reactive species in the process.