Chemical evolution would have required a continuous supply of energy to create the first life. But are the energy sources that have been proposed for chemical evolution realistic? In this episode of Long Story Short, explore some of the challenges chemical evolution would have faced in order to harness the energy needed to originate the first life. This is one of several episodes about the origin of life.
For more episodes in Long Story Short, see: • Long Story Short
REFERENCES CITED:
(1) Branscomb, E.; Russell, M. J. Frankenstein or a submarine alkaline vent: who is responsible for abiogenesis? Part 2: as life is now, so it must have been in the beginning. BioEssays 2018, 40 (8), 1700182. Kitadai, N.; Maruyama, S. Origins of building blocks of life: A review. Geoscience Frontiers 2018, 9 (4), 1117-1153. Miller, S. L. A production of amino acids under possible primitive earth conditions. Science 1953, 117 (3046), 528-529.
(2) Note. Technically cells can absorb some forms of energy like heat, but without a way to harness the energy it’s not useful and can even be damaging.
(3) Note. Technically, there are five complexes involved in oxidative phosphorylation but only these three are relevant to the discussion at hand. Complex II (succinate dehydrogenase) also participates in the citric acid cycle and runs parallel to Complex I (NADH ubiquinone oxidoreductase) except Complex II receives electrons from FADH2 but doesn't pump protons and Complex I receives electrons from NADH. Complex V is the wonderful ATP synthase (or ATPase when it runs in reverse and breaks down ATP to pump protons backward to build up the gradient).
(4) Note. Also known as “free radicals”, they damage molecules like DNA by altering or breaking covalent bonds and are a major source of what causes us to age.
(5) Vu Huu, K.; Zangl, R.; Hoffmann, J.; Just, A.; Morgner, N. Bacterial F-type ATP synthases follow a well-choreographed assembly pathway. Nature communications 2022, 13 (1), 1-13.
(6) Walker, J. E.; Saraste, M.; Gay, N. J. The unc operon nucleotide sequence, regulation and structure of ATP-synthase. Biochimica et Biophysica Acta (BBA)-Reviews on Bioenergetics 1984, 768 (2), 164-200.
(7) Lane, N. The vital question: energy, evolution, and the origins of complex life. WW Norton & Company, 2015; p 82.
(8) Note. ~3k protons/sec per ATP synthase. Creating ~326 ATP molecules/sec. Biovisions at Harvard University: Electron transport chain • Electron transport chain .
(9) Note. Average human = 70kg. ATP = 507 g/mol. A human therefore weighs as much as about 140 moles of ATP. A human consumes about 140 * 6.022X10^23 = 8.43X10^25 ATP molecules per day. 1 day = 86,400 seconds. Therefore, each second, a human consumes 9.75X10^20 ATP molecules. Basically 10^21 ATP molecules per second, which is "a billion trillion ATP molecules per second".
(10) Note. Producing ADP also requires many complex enzymes, each produced with the help of energy from ATP: pyrophosphokinase, amidophosphoribosyltransferase, GAR synthetase, GAR transformylase, FGAM synthetase, AIR synthetase, AIR carboxylase, SAICAR synthetase, adenylosuccinate lyase, AICAR transformylase, IMP cyclohydrolase, and adenylosuccinate synthase. Voet, D.; Voet, J. G.; Pratt, C. W. Fundamentals of biochemistry: life at the molecular level. John Wiley & Sons, 2016; pp 802-808.
(11) Note. Some machines operate on other molecules with high energy-transfer potential, like GTP but the problems there are the same as with ATP. .
(12) Lane, N. The vital question: energy, evolution, and the origins of complex life. WW Norton & Company, 2015; p 106.
(13) Note. Via a pH gradient that provides a high pH (alkaline) solution that mixes with the neutral or lower pH seawater.
(14) Miller, B.; England, J. Hot Wired. 2020. inference-review.com/article/... (accessed 2022 April 28).
(15) Jackson, J. B. Natural pH gradients in hydrothermal alkali vents were unlikely to have played a role in the origin of life. Journal of molecular evolution 2016, 83 (1), 1-11.
(16) Jackson, J. B. Natural pH gradients in hydrothermal alkali vents were unlikely to have played a role in the origin of life. Journal of molecular evolution 2016, 83 (1), 9.
(17) Lane, N. The vital question: energy, evolution, and the origins of complex life. WW Norton & Company, 2015; p 168.
(18) Bonora, M.; Patergnani, S.; Rimessi, A.; De Marchi, E.; Suski, J. M.; Bononi, A.; Giorgi, C.; Marchi, S.; Missiroli, S.; Poletti, F.; et al. ATP synthesis and storage. Purinergic Signal 2012, 8 (3), 343-357.
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