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Green powerGod’s solar power plants amaze chemists
Green plants are a beautiful part of Earth’s environment, and they are essential for life. God created them on the 3rd day of Creation Week (Genesis 1:10–13), before animals, and even before the sun.1 At the beginning of creation, humans and all animals were herbivores (Genesis 1:29–30). Even now, plants are the basis of the food chain, because they don’t require their own food but make it from sunlight via photosynthesis. In this process, they also produce the oxygen (O2) which is essential for all air-breathing life. Photosynthesis is therefore one of the most important chemical reactions on Earth. If we could duplicate it, it would probably solve all the world’s energy problems.2 But even the most ingenious chemists have yet to match the ingenious machinery of the humble plant. Water blasting problemThe unique … arrangement … is essential … because it must be able to store the energy from four photons, and hold water molecules in just the right positions. This structure had to be complete otherwise it would not work at all …. Therefore it could not be built up gradually by small changes by natural selection … because an incomplete intermediate system is no use at all, so it would not be selected. The key to photosynthesis is breaking up a molecule of water into hydrogen and oxygen. The hydrogen can then combine with CO2 from the air to make sugars, which the plant (and herbivores) can use for food. All this occurs in the molecules called chlorophylls, which are responsible for the greenness of plants. But breaking up water requires an enormous amount of energy—basically the amount released when hydrogen is burned to form water in the first place. One problem is the very nature of light itself. Light is a form of energy, but it comes in ‘packets’ called photons. If the photon energy is not large enough to break the water molecule, then it won’t matter how many of them there are (i.e. how bright the light is). But a photon that is energetic enough3 to break water would also shatter most biological molecules in the process. Yet we don’t see exploding leaves! A few years ago, two chemists from Yale University, Gary Brudvig and Robert Crabtree, made an artificial system that managed to produce oxygen.4 However, they had not worked out how to use light energy, so instead they used the chemical energy of powerful bleaches.5 And even then, it produced only 100 O2 molecules before being destroyed. Yet it was a great achievement, by human standards, to make something that didn’t fall apart immediately.6 Ingenious solution7It turns out that in there is a special assembly called Photosystem II (named because it was discovered second). A photon strikes this, and it is channeled into a type of chlorophyll called P680. There it knocks out an electron from an atom, and this energetic electron eventually helps make sugars from CO2. But then, the P680 must replenish the lost electron. This is a big problem for artificial photosynthesis—human chemists have also so far been unable to produce a system that replenishes the electrons knocked out by the photons. Photosynthesis would have quickly ground to a halt without this, so how are the electrons replaced? They come from a special catalytic core, which removes the required electrons from water, again with the help of light. The light breaks two molecules of water into a molecule of oxygen, four electrons and two hydrogen ions. The core has a unique arrangement of atoms, with an unusual cube of three atoms of Mn, one Ca and four O, attached to a single Mn [update: see Where Water Is Oxidized to Dioxygen: Structure of the Photosynthetic Mn4Ca Cluster, Science 314(5800):821–825, 3 November 2006; Learning how nature splits water]. This core builds up enough energy, in the form of redox potential,8 in stages by absorbing four photons. The redox potential of water is +2.5 V, while each photon raises the catalytic core’s redox potential by 1 V. So after the third stage, there is enough energy for the single Mn to remove an electron from a water molecule, leaving an OH radical and H+ ion. Then the catalytic core gets to the fourth stage, and provides the Mn atom with enough power to attack the OH radical and leaves a highly reactive O atom and another H+ ion. At this moment, the Ca atom in the cube plays its essential role. It is holding another water molecule in just the right place, so it can be attacked by this O atom, producing an O2 molecule, two more H+ ions and two electrons. The unique Mn3CaO4–Mn arrangement is present in all plants, algae and cyanobacteria, which suggests that this arrangement is essential. Not surprising, because it must be able to store the energy from four photons, and hold water molecules in just the right positions. This structure had to be complete otherwise it would not work at all—in splitting water and replenishing electrons. Therefore it could not be built up gradually by small changes by natural selection. This is because an incomplete intermediate system is no use at all, so it would not be selected. And even this core would be useless without many other coordinated features. For example, as above, the energy involved is damaging for biological molecules. Yet there are key proteins required, but must be constantly repaired, so these mechanisms must be in place too. In fact, instability of these proteins made it hard to work out the core’s structure.9 If the most intelligent human designers can’t duplicate photosynthesis, then it’s perfectly scientific to believe that photosynthesis had a far more intelligent designer. This is especially so since Darwinian processes could not have generated photosynthesis, because there are too many intricate mechanisms necessary for it to work at all.10 Plants were there right at the beginningRecent research indicates that there was oxygen even in the ‘oldest’ rocks on earth, which evolutionists ‘date’ to 3.7 billion years old (Ga).11 This in turn suggests that there were green plants to produce it. However, evolutionists claim that the earth was being bombarded by meteorites till about 3.8 Ga. Yet this latest research shows that life existed almost as soon the earth was able to support it. There is just no room for ‘billions and billions of years’ for life to evolve. And this life was not just the simplest type, but was advanced enough to photosynthesize.12 Also, this research is devastating for chemical evolutionary theories of the origin of life.13 The famous gas discharge experiments by Stanley Miller and Harold Urey must exclude free oxygen, because oxygen destroys organic molecules, and makes them impossible to form in the first place. But if oxygen is as old as the oldest rocks, there is no geological evidence to support the hypothetical oxygen-free atmosphere required. References
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