Category: Uncategorized

ACTUAL PROTEINS. “Now let us ask if the universe can have created all these proteins since its inception 13.8 billion years ago. There are roughly 10 to the 80th particles in the known universe. If these were doing nothing, ignoring space-like separation, but making proteins on the shortest timescale in the universe, the Planck timescale of 10 raised to the −43 seconds, it would take 10 raised to the 39th power times the lifetime of our universe to make all possible proteins of length 200, just once.” https://lnkd.in/euEN3Eh View in LinkedIn

THEORETICAL PROTEIN POSSIBILITIES. “A biological protein can range from perhaps fifty amino acids long to several thousands. A typical length is three hundred amino acids long. Then let us consider all possible proteins that are two hundred amino acids in length. How many are possible? Each position in the two hundred has twenty possible choices of amino acids, so there are 20 × 20 × 20 . . . 200 times, or 20 to the 200th power, which is roughly 10 to the 260th power possible proteins of 200 amino acids in length.” https://lnkd.in/euEN3Eh View in LinkedIn

FROM PARTICLES TO PROTEINS. “Has the universe in 13.8 billion years of existence created all the possible fundamental particles and stable atoms? Yes. Now consider proteins. These are linear sequences of twenty kinds of amino acids that typically fold into some shape and catalyze a reaction or perform some structural or other function.” https://lnkd.in/euEN3Eh View in LinkedIn

PHYSICAL LIMITS. “We reach the final level of complexity, at least at a biological level. We can’t run at 40 mph (although a spurt of c. 23 mph is by no means negligible), nor fly (but a gin and tonic at 38000 feet has its merits), nor swim the Pacific (although the free diving record of 800 feet deserves a salute), but we can out-think any other organism that has ever evolved.” https://lnkd.in/euEN3Eh View in LinkedIn

END IN SIGHT. “These, in their various ways, indicate that however complex nervous systems may get, there are definite limits to what in the end is possible.” https://lnkd.in/euEN3Eh View in LinkedIn

BRAIN LIMITS. “But of all the limits to complexity perhaps the most interesting is the one that concerns the evolution of nervous systems. It is well known that in terms of metabolic energy nervous systems are cripplingly expensive: the retina of the blow-fly alone accounts for an extraordinary 8% of the total energy budget of the insect.” https://lnkd.in/euEN3Eh View in LinkedIn

GOOD ENOUGH. “RuBisCo maximises the chance that a CO2 molecule rather than a molecule of the much more abundant oxygen reacts with the substrate, by grabbing the biphosphate molecule and twisting it The trade-off is that this twisting makes it hard for RuBisCo to release the end product-hence its slowness. Arguably, RuBisCo is not inefficient, it's as good as it could get.” http://answersinscience.org/EvolGreatestMistakes-NewSci%20081107.pdf View in LinkedIn

GREAT OXYGENATION EVENT. “RuBisCo's failings have been attributed to the fact that when it evolved, levels of oxygen were far lower than they are now, so mistaking oxygen for CO2 would have mattered far less. Research published last year, however, suggests that far from being a dunce, RuBisCo has a streak of genius. O2 and CO2 have some similar physical features that make it hard for any enzyme to discriminate between them.” http://answersinscience.org/EvolGreatestMistakes-NewSci%20081107.pdf View in LinkedIn

NEGATIVE SELECTION. "Mutant swarm generation might be prevented only if negative (or purifying) selection eliminated the great majority of newly arising mutant genomes, which is not the case. Current evidence suggests that a considerable proportion of mutants might be eliminated by negative selection, but it is not clear whether all mutations considered lethal by standard measurements of viral production might not be in reality low fitness variants that can populate low frequency levels of mutant spectra, either because they can replicate minimally or because they are helped by complementation." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

FRAGMENT FROM NATURE: this meditation considers viral hybrid swarms and quasispecies, which cloud traditional thinking about species. As usual, viral entities thumb their noses at biological norms, and on the topic of species, it is a spectacular thumbing. Viruses challenge biologists to rethink many old assumptions. View in LinkedIn