Polymers are small molecules that can be bonded together to create larger molecules. Complex carbohydrates are made from small simple sugars joined together, and giant protein molecules are simply a series of smaller amino acid molecules bonded together. The prefix poly identifies this type of molecular addition.
For instance, polysaccharides are large carbohydrates composed of multiple saccharide sugar units. The chemical reaction that powers polymer formation is known by several names, including dehydration synthesis and condensation reaction. So a dehydration synthesis joins two smaller units together with the loss of one water molecule. Moulton, Ed. All rights reserved including the right of reproduction in whole or in part in any form.
As far back as the17th century, people were using a conducting form of carbon in one of the most ubiquitous data storage tools on the planet — the pencil.
The graphite running through pencils has a layered structure and each layer is a honeycomb lattice, like tessellated benzene rings where each carbon atom is now bonded to three nearest neighbours.
Researchers have also exploited these weak interlayer bonds in graphite substrates that can be easily cleaned by removing the top layer with a piece of sticky tape. Thanks to the curiosity of Andre Geim and Kostya Novoselov in their legendary Friday night experiments on these discarded bits of sticky tape, the phenomenal properties of a single or very few layers of carbon — now known as graphene — have been keeping researchers and funders busy for over a decade since, and will likely continue to do so for decades to come.
Even before the discovery of graphene by Geim and Novoselov at the University of Manchester in , studies of carbon nanotubes — discovered in by Sumio Iijima — had given a glimpse of the kind of mechanical and electronic properties that emerge from a single layer of carbon. One of the attributes of graphene that has excited researchers recently is the way the properties of materials comprising more than one layer of graphene can be tuned by the presence of other 2D materials, and even by the angle or twist between graphene layers themselves.
And I would bet my hat that there is more to discover in other forms of nanocarbon in the future. So we literally live, eat and breathe carbon. It feeds our industries, inspires our labs, and is the cause and potential solution to some of the greatest challenges facing the planet.
Carbon is so ubiquitous across living organisms that radioactive measurements of the carbon composition can be used to date them — so carbon owns time too. Be it work, rest or play there is nothing you can do that carbon does not influence, govern or facilitate. Like it or not, carbon is King of the Elements.
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Sign in Register. Enter e-mail address Show Enter password Remember me. These different molecules are called isomers. The fifth reason is that all of the electrons that are not being used to bond carbon atoms together into chains and rings can be used to form bonds with atoms of several other elements. The most common other element is hydrogen, which makes the family of compounds known as hydrocarbons.
But nitrogen, oxygen, phosphorus , sulfur , halogens , and several other kinds of atoms can also be attached as part of an organic molecule. There is a huge number of ways in which they can be attached to the carbon-atom branches, and each variation makes a molecule of a different compound. Elements sharing a column of the periodic table often have similar properties, so perhaps silicon is a viable biological backup to carbon? Science fiction writers have seized on this option more than once.
Kirk and Leonard Nimoy as Mr. Spock—in which the crew of the Enterprise discovers a race of intelligent and potentially dangerous silicon-based life forms shaped like rocks.
The concept of the show was fun, especially with the satisfying peaceful resolution as rocks and humans learned to get along. But the mineralogical premise was flawed; silicon is a biological dead end. Once formed, those silicon-oxygen bonds are too strong and too inflexible to do interesting chemistry.
You simply cannot base a biosphere on a single-minded element like silicon. Keep going, but you will search in vain for another promising elemental option. True, your eye might fall on iron, element 26, the fourth most abundant element in the crust after oxygen, silicon and magnesium.
Why not iron? Bond with oxygen? Sure, form red rust with ionic bonds. Bond with sulfur? Iron bonds to arsenic and antimony, to chlorine and fluorine, to nitrogen and phosphorus, even to carbon in a variety of iron carbide minerals.
And if no other elements are handy, iron happily bonds with itself in iron metal. Such a diverse bonding portfolio might seem ideal for the core element of life. But iron has a flaw. It readily forms minerals with big crystals, but it shies away from making small molecules. Life demands a huge variety of molecules, with chains and rings and branches and cages—tricks that iron rarely attempts.
And so we are left with carbon, the most versatile, most adaptable, most useful element of all. Carbon is the element of life. What is our role in the evolutionary scheme of things, in the great carbon symphony? Humans are at once ordinary and unique. On the one hand, we are just another evolutionary step in a four-billion-year story that will likely continue long after our lineage has gone extinct or morphed into some new species.
At the same time, our human species does possess unprecedented abilities. We are unique in the history of life in our technological prowess to adapt and alter our environments at scales from local to global. We are unique in our inventive exploitation of other species—animal, vegetable and microbial. We are unique in our exuberant desire and ability to explore beyond our world, perhaps eventually to colonize other planets and moons.
Humans are unique among life-forms because of the frenetic pace of the changes we impose. We are altering the planet at rates much faster than any prior species—at rates exceeded only by the sudden cataclysms of volcanoes exploding and rocks falling from the skies. Microbes took hundreds of millions of years to oxygenate the atmosphere, and perhaps a billion years more to oxygenate the oceans.
Multicellular life required tens of millions of years to colonize the land after the earliest tentative encroachments. These changes were profound, but they occurred over geological timescales that enabled life and rocks to co-evolve gradually. If humans pose a unique threat to Earth, as some scholars fear, then it is the unprecedented rate of environmental change that carries the greatest risk for damage to the biosphere. That being said, the rocks and the varied microbes that live among them will do just fine whatever injuries we might do to our home and, inadvertently, to our own species.
Earth will go on, life will go on, and the powerful process of evolution by natural selection will ensure that new creatures continue to inhabit every niche on the planet. Nothing exists in isolation; all are essential parts of the whole. Earth grows the solid crystals of carbon—sturdy foundation stones of land and oceans alike. Air holds the molecules of carbon that embrace us all—forever cycling, protecting and sustaining life. Fire, born of carbon, energizes the world, while providing unrivaled molecular variety to the material and living worlds.
Water, which gave birth to carbon life, nurtures that life as it evolves and radiates to every corner of the globe. In a crescendo of exquisite harmony and complex counterpoint, each essence of carbon celebrates, and is celebrated by, the others. Humans have learned to impose their own urgent themes and ever-accelerating tempi on this ancient score.
We strip earth of its minerals. We flood air with our waste.
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