43 posts tagged Life
Seven Molecules’ Claim to Fame Chemistry: These infinitesimal celebrities shape us and our world.
From drinking water to DNA, from caffeine to carbon dioxide, and from Lipitor to Viagra—that is from atorvastatin to sildenafil citrate—molecules define our personalities, regulate our abilities, and dictate our feelings. Invisible to the human eye, many of them are biological celebrities: They famously smell or stink, make us feel depressed or elated, pollute our planet or save our lives. Even the most destructive molecules are so essential to our civilization that modern industry wouldn’t exist without them. Here we describe seven of the most prominent corpuscular figures, without which our life would be completely different. In fact, without some of them, scientists say, there’d be no human life at all.
Cellular “tinkering” is critical for establishing a new engineering discipline that will lead to the next generation of technologies based on life’s building blocks.
Engineering began as an outgrowth of the craftwork of metallurgical artisans. In a constant quest to improve their handiwork, those craftsmen exhaustively and empirically explored the properties—alone and in combination—of natural materials. The knowledge accumulated from this exploration and experimentation with natural building blocks eventually led to today’s modern technologies. We can now readily build things like super-lightweight cars and electrical circuits containing billions of transistors that encode highly sophisticated functions, using reliable design and manufacturing frameworks—a vast leap from artisanal craft.
Today, there is a parallel progression unfolding in the field of synthetic biology, which encompasses the engineering of biological systems from genetically encoded molecular components.1-7 The first decade or so of synthetic biology can be viewed as an artisanal exploration of subcellular material. Much as in the early days of other engineering disciplines, the field’s focus has been on identifying the building blocks that may be useful for constructing synthetic biological circuits—and determining the practical rules for connecting them into functional systems. This artisanal tinkering with cells is necessary for arriving at a rigorous understanding of subcellular construction material and for determining the extent to which it can be manipulated. (via Engineering Life | The Scientist Magazine®)
Does life have a purpose?
Nobody expects atoms and molecules to have purposes, so why do we still think of living things in this way?
One of my favorite dinosaurs is the Stegosaurus, a monster from the late Jurassic (150 million years ago), noteworthy because of the diamond-like plates all the way down its back. Since this animal was discovered in the late 1870s in Wyoming, huge amounts of ink have been spilt trying to puzzle out the reason for the plates. The obvious explanation, that they are used for fighting or defence, simply cannot be true. The connection between the plates and the main body is way too fragile to function effectively in a battle to the death. Another explanation is that, like the stag’s antlers or the peacock’s tail, they play some sort of role in the mating game. Señor Stegosaurus with the best plates gets the harem and the other males have to do without. Unfortunately for this hypothesis, the females had the plates too, so that cannot be the explanation either. My favourite idea is that the plates were like the fins you find in electric-producing cooling towers: they were for heat transfer. In the cool of the morning, as the sun came up, they helped the animal to heat up quickly. In the middle of the day, especially when the vegetation consumed by the Stegosaurus was fermenting away in its belly, the plates would have helped to catch the wind and get rid of excess heat. A superb adaptation. (Sadly for me, no longer a favoured explanation, since latest investigations suggest that the plates may have been a way for individuals to recognise each other as members of the same species).
READ OF THE DAY… keep on reading
1) Infinite players cannot say when their game began, nor do they care. Their game is not bounded by time. Indeed, the only purpose of the game is to keep it from coming to an end, to keep everyone in play.
2) Since each play of an infinite game eliminates boundaries, it opens players to a new horizon of time. Finite players play within boundaries; infinite players play with boundaries.
3) Infinite players regard their wins and losses in whatever finite games they play as but moments within a larger field of continuing play that extends beyond the finite game.
4) The rules of an infinite game must change in the course of play. The rules are changed when the players of an infinite game agree that the play is imperiled by a finite outcome—that is, the victory of some players and the defeat of others.
5) To be playful is not to be trivial or frivolous, to act as though nothing of consequence will happen. On the contrary, when we are playful with each other we relate as free persons, and the relationship is open to surprise; everything that happens is of consequence.
6) What is your future, and mine, becomes ours. We prepare each other for surprise.
7) Infinite players do not oppose the actions of others, but initiate actions of their own in such a way that others will respond by initiating their own.
8) Our social existence has an inescapably fluid character. Society is a finite game. Culture is an infinite game. Where society has boundaries, culture has a horizon. Every move an infinite player makes is toward the horizon.
9) It is apparent to infinite players that wealth is not so much possessed as it is performed.
10) Infinite players are concerned not with power, but vision, and the freedom to change ourselves.
Wildcat: Like the writer of this essay quoting these ten points I cannot recommend enough this book.
Evolution skeptics argue that some biological structures, like the brain or the eye, are simply too complex for natural selection to explain. Biologists have proposed various ways that so-called ‘irreducibly complex’ structures could emerge incrementally over time, bit by bit. But a new study proposes an alternative route.
Instead of starting from simpler precursors and becoming more intricate, say authors Dan McShea and Wim Hordijk, some structures could have evolved from complex beginnings that gradually grew simpler — an idea they dub “complexity by subtraction.” Computer models and trends in skull evolution back them up, the researchers show in a study published this week in the journal Evolutionary Biology.
Some biological structures are too dizzyingly complex to have emerged stepwise by adding one part and then the next over time, intelligent design advocates say. Consider the human eye, or the cascade that causes blood to clot, or the flagellum, the tiny appendage that enables some bacteria to get around. Such all-or-none structures, the argument goes, need all their parts in order to function. Alter or take away any one piece, and the whole system stops working. In other words, what good is two thirds of an eye, or half of a flagellum?
Describing how living organisms emerged from Earth’s abiotic chemistry has remained a conundrum for scientists, in part because any credible explanation for such a complex process must draw from fields spanning the reaches of science. A new synthesis by two Santa Fe Institute researchers offers a coherent picture of how metabolism, and thus all life, arose. The study, published December 12, 2012, in the journal Physical Biology, offers new insights into how the complex chemistry of metabolism cobbled itself together, the likelihood of life emerging and evolving as it did on Earth, and the chances of finding life elsewhere. “We’re trying to bring knowledge across disciplines into a unified whole that fits the essentials of metabolism development,” says co-author Eric Smith, a Santa Fe Institute External Professor. Creating life from scratch requires two abilities: fixing carbon and making more of yourself. The first, essentially hitching carbon atoms together to make living matter, is a remarkably difficult feat. Carbon dioxide (CO2), of which Earth has plenty, is a stable molecule; the bonds are tough to break, and a chemical system can only turn carbon into biologically useful compounds by way of some wildly unstable in-between stages.