Evolutionary Bioenergetics of Protocells
Bioenergetics is central to our understanding of living systems, though there has been very less research in field of finding the origins of life. Understanding the origin of cellular life on Earth requires the discovery of plausible pathways for the transition from complex prebiotic chemistry to simple biology, defined as the emergence of chemical assemblies capable of Darwinian evolution. A coherent pathway which starts from no more than rocks, water and carbon dioxide and leads to the emergence of the strange bioenergetics properties of living cells has been traced back to what is now called as Protocells. A Protocell is found to be the first form of a cell before true cells arose. They have a lipid protein and carry out energy metabolism. It is theorised that at the origin of life the first Protocells must have needed a vast amount of energy to drive their metabolism and replication, as enzymes that catalyse very specific reactions were yet to evolve. Most energy flux must have simply dissipated without use. Humans consume more than a kilogram (more than 700 litres) of oxygen every day, exhaling it as carbon dioxide. The simplest cells, growing from the reaction of hydrogen with carbon dioxide, produce about 40 times as much waste product from their respiration as organic carbon (by mass). In all these cases, the energy derived from respiration is stored in the form of ion gradients over membranes.This strange trait is as universal to life as the genetic code itself. The scientists Lane and Martin showed that bacteria are capable of growing on no more than hydrogen and carbon dioxide are remarkably similar in the details of their carbon and energy metabolism to the far-from-equilibrium chemistry occurring in a particular type of deep-sea hydrothermal vent, known as alkaline hydrothermal vents. Based on measured values, they calculate that natural proton gradients, acting across thin semi-conducting...
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