Theoretical origin of life; bioelectrical energy (Introduction)

by David Turell , Friday, August 21, 2015, 19:33 (3168 days ago) @ David Turell

The presence of mitochondria and bioelectrical energy allowed life to become multicellular:-http://www.the-scientist.com/?articles.view/articleNo/43668/title/Opinion--Life-s-X-Factor/-"...there is an evolutionary gulf between the structural complexity of even the most multifaceted prokaryotes (still cyanobacteria, which have genomes of up to 12 megabases (compared with Loki's meagre five) and standard protists, with genomes ranging up to 100,000 megabases, coding for vastly more complex morphologies.-"In my latest book, The Vital Question, I argue that the answer lies in energy—specifically, the totally unanticipated mechanism of membrane bioenergetics. Essentially all cells rely on electrochemical ion gradients (usually proton gradients) across membranes to drive the synthesis of adenosine triphosphate (ATP). Autotrophs rely on membrane bioenergetics to drive carbon fixation, too. In fact, all carbon and energy metabolism depends on proton gradients across membranes.-***-"Any student of evolution can still see the marks of this constraint on Earth's myriad life forms. Bacteria and archaea remained morphologically simple, despite their metabolic virtuosity, for a staggering 4 billion years.-***-"So how did eukaryotes escape this energetic stranglehold? Through the rare endosymbiosis that gave rise to mitochondria. The advantage of mitochondria had nothing to do with oxygen, or even compartmentalisation: it was all about genes—loss of them. Mitochondria ultimately lost 99 percent of their genes. Yet they invariably retain a small handful of genes that are necessary to control respiration locally, giving eukaryotes multibacterial power without the overhead.-***-"In The Vital Question, I posit that the basal traits of eukaryotes were forged in the crucible of endosymbiosis between prokaryotes, which drove the evolution of sex, the nucleus, the germline-soma distinction, aging, and death. These ideas might be wrong, but they are testable, and could have considerable explanatory power. I think we'll only understand why life is the way it is when we bring energy into the equation."-Comment: Yes sufficient energy is needed, but information is needed also