"Oxidative stress occurs when a biological system cannot properly detoxify or repair damage caused by reactive oxygen species (ROS). ROS form as a natural byproduct of normal metabolism and have important roles in cell signaling. However, during times of environmental stress (such as for example, UV or heat exposure) ROS levels can increase dramatically, which can result in diseases (like cancer, cardiovascular disease and neurodegenerative diseases) and significant damage to cell structures. Oxidative stress and free radical chemistry are popularly understood to be important aspects of biochemistry, but the underlying science is more complex than the public understands. For those who seriously study oxidative processes, a rigorous mechanistic approach both reveals much complexity and also shows the many gaps in our knowledge"-- Provided by publisher.