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Abstract EANA2024-119



ROS: Possible Implications for the Emergence of Life

Sohan Jheeta
noRCEL


How did life begin on the Earth? Although there are more that twenty hypotheses in literature which claim the way forward for the emergence of life, in this vein, the reactive species of oxygen may have played an equally pivotal role. Whilst it is true that the chemistry of Reactive Oxygen Species (ROS) has been known about since the 1950’s (and has often been referred to as free radicals in the commercial sector), its part in the emergence of life was, perhaps, first put forward by Prof Nick Lane (UCL) in his aptly named book entitled: “OXYGEN: The Molecule that Made the World (2003).” However, according to the molecular orbital theory it now considered that dioxygen (also referred to as a singlet, 1O2) is a highly unstable molecule compared to triplet oxygen 3[O2]—the latter is more stable as its two π* electrons have parallel spins. As a result of its instability, singlet dioxygen can form numerous reactive species, as exemplified as follows: superoxide (•, peroxide (•) anions; hydrogen peroxide (H2O2), hydroxyl radicals (•OH), hydroxyl ion (OH–), Nitric oxide (NO.), nitrogen dioxide (NO2) and peroxynitrite (ONOO–).

 

Reactive species of oxygen can react with numerous other elements to form innumerable varieties of ions, free radicals and molecules; in essence, ROS can either donate unpaired electrons, or alternatively by accept electrons from other species. The fact that these newly formed exotic species are generated by ROS, warrants further investigation into the possible role it played in the emergence of life on Earth.