The fuel cell par excellence

If, like me, you happen to live in the country, make an effort to stop and take in the verdant landscape on your way to work tomorrow. Ask yourself how something so utterly beautiful can become so pitifully lifeless within a few short months. The answer lies within each cell of each of those tens of thousands of leaves. In truth, the plant cell is the model to which its animal cousin aspires. As far as fuel efficiency goes, a plant cell is about as close to 100% as is theoretically measurable. How? This is down to the humble chloroplast which gives plants their distinctive green colour. Each cell contains a chloroplast which is rich in chlorophyll. It is the latter which contains an energy unit so efficient that scientists would sell their soul to even get close to replicating it.

As the last leaves fell off the trees in North America in 2011, a lady called Lyn Margulis passed away at the age of 73. Of all the science which I have thus far read, without question, the endosymbiont theory proposed by this remarkable lady is the most profound, thought provoking development to which I have been exposed. Put simply, she put forward the theory that millions of years ago, single celled bacteria became incorporated in to the existing cells of what we now call animals and plants. Just as every plant cell contains an energy powerhouse called a choroplast, every animal cell contains something called a mitochondrion. The mitochondrion is truly the workhorse of our cells and produces the vast amounts of energy upon which we rely as a species. She proposed this theory when she noticed that the DNA in a chloroplast and a mitochondrion is different to the DNA found in the respective nuclei of animal and plant cells. So what I hear you say. Well, the amazing discovery was that both contained the circular DNA known to be common to bacterial cells. Bacteria, of course, are one of the most primitive life forms on the planet (if you don't include the 650 or so Members of Parliament). Just like the MPs, the bacteria have become highly skilled at surviving against seemingly impossible odds and are able to thrive in highly challenging conditions. Bacteria are to be found at the bottom of the deepest ocean, on Antarctica, in Volcanoes and in every extreme of temperature or chemicals known to man. With water and sunlight, plants are equally versatile. While Watson and Crick hit the big one with their elucidation of the structure of DNA in 1953, I believe that the theory put forward by Lyn Margulis was even more important because she has shown us the way, at least in thoery, to survive.

Such is the unrivalled efficiency of a plant cell, the tree can afford to shed all its leaves and subsist on its stored energy for half the year having created so much in the previous half. Broadly speaking, this is the challenge facing the energy scientists as the world population continues to grow apace like a bacterial colony. Solar panels, wind turbines and the rest are all very well but they continue to be poor imitators of the billions of plant cells which they seek to emulate.