According to Cooper (1988) '... a literature review uses as its database reports of primary or original scholarship, and does not report new primary scholarship itself. The primary reports used in the literature may be verbal, but in the vast majority of cases reports are written documents.
Reactive oxygen species. Reactive oxygen species (ROS) are chemically reactive chemical species containing oxygen. Examples include peroxides, superoxide, hydroxyl radical, and singlet oxygen. In a biological context, ROS are formed as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling and homeostasis.
The role of the enzyme is to reduce the activation energy, by bringing specific molecules together, rather than relying on random collisions) Action on specific Substrates. Enzymes are substrate specific, meaning only one particular substrate molecule can work with one particular enzyme. This is due to the reciprocally shaped active site. Since the enzyme is never chemically alter by a reaction, it can be reused in subsequent reactions â enzyme controlled reactions are always reversible.