Ridley States: \"Life consists of the capacity to reverse the drift towards entr

Question

Ridley States: "Life consists of the capacity to reverse the drift towards entropy and disorder, at least locally – to use information to make local order from chaos while expending energy. Essential to these three skills are three kinds of molecule in particular – DNA for storing information, protein for making order, and ATP as the medium of energy exchange. How these came together is a chicken-and-egg problem. DNA cannot be made without proteins, nor proteins without DNA. As for energy, a bacterium uses up fifty times its own body weight in ATP molecules in each generation. Early life must have been even more profligate, yet would have had none of the modern molecular machinery for harnessing and storing energy. Wherever did it find enough ATP?" ** Answer Ridley's question with lots of details about black smoker vents, voltage gradients, and RNA.

Explanation / Answer

The chicken and egg problem has been haunting the science since the age of first human civilization. What did first came is it DNA or is it protein. If it is DNA then how does it formed without the aid of proteins, or is it protein came first then how protein came without DNA. The answer is ribozymes. Ribozymes are RNA molecules that can catalyse chemical reactions like the protein enzymes.It is shown that ribozyme can be genetic material(RNA) and can be enzyme(Protein) and lead to the RNA world hypothesis suggesting RNA may have been important in the evolution of prebiotic self-replicating systems.

Though ATP is the best energy currency, not all life forms depend on ATP for energy.Anerobic bacteria use ATP synthase to pumb out the H+ and maintain a pH. In hydrothermal vents, these bacteria depend sulfur compounds, such as hydrogen sulfide to produce organic material.They also use fermentation for getting enough ATP.In Substarte level phosphorylation, phosphorylation is coupled with a highly exergonic chemical reaction. Bacteria that depends on Fermentation depend on Substarte level phosphorylation for ATP.

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