Saturday, December 20, 2008

How the celebration we call life got started.

HOW NONCYCLIC PHOTOSYNTHESIS JUMPSTARTED LIFE, HILLARY CLINTON AND EVERYTHING THAT FILLS A NICH.
True plants use carbon dioxide and water (along with nitrogen and phosphorus from the soil) to make organic compounds and produce oxygen as a waste product. When the plant needs to use any of the energy it stored, it uses oxygen to “burn” its fuel, generating water and carbon dioxide as byproducts of that process.
To take advantage of the energy stored in the plants, animals eat the plants directly or eat other animals that do. Like the plants, they use oxygen during metabolism and produce waste water and carbon dioxide. Both plants and animals need additional water for a variety of functions: For example, the transport of nutrients up from the roots is powered by the evaporation of water from the leaves and animals use water to regulate temperature through evaporative cooling and to dispose waste products. A small fraction of the earth’s living things are anaerobic or harvest inorganic chemical energy, and so do not fit into this cycle.

ENERGY CYCLE IN PLANTS
The photon energy: “sunlight” activates electrons, which are removed from the chlorophyll before they can reemit that energy. These “excited” electrons are used to charge a membrane battery, which is used to make the energy transfer compound, adenosine triphosphate (ATP). In the process the energized electrons, having been activated days or even years earlier, lose their energy and are discarded in energy poor carbon dioxide. The ATP is used as a carrier for the electron energy. Every organism faced nutrient poor conditions and so for every 99.9 percent of new life forms that evolved only one-tenth of one percent survived while all the rest are now extinct. --James L. Gould, Carol Grant Gould
It was the unique property of water with two hydrogen atoms each with a positive charge and one oxygen atom with a negative charge referred to as nonpolar molecules that allow weak electro static associations (hydrogen bonds). Their unique geometry allowed the self-repairing, bilayer membrane of the living cell. Modern cells protect themselves from the environment with bilayer membranes to which specific chemical doors and pumps have been added to help control molecular in-and-out traffic.
Hydrogen Cyanide, for example, is readily formed from ammonia and methane and then converted into the nucleotide adenine, which is also the backbone of ATP. –Chemical Evolution and the Origin of Life, By Richard E. Di ckerson; Scientific American, September, 1978
Many meteorites and comets contain abundant inorganically formed organic compounds. Natural selection must have been at work from the very onset, favoring liposomes with the most useful chemistry favoring those with the most useful building blocks and excluding those that might be toxic. At this point in time most organisms were autotrophs—that is, creatures that took energy or energy-rich materials from the nonliving world around them—as apposed to heterotrophs, which eat other organisms (you).
The next step in the evolution of living organisms was the development of cyclic photosynthesis—cyclic because the electron energized by an incoming photon from the sun is quickly returned to the chlorophyll molecule from which it came. Chlorophyll is embedded in a membrane along with the enzymes that steal the activated electron and harvest its energy; that energy is used to charge the membrane, and the electrostatic potential created is later employed to make ATP.
It takes about two photons to charge the membrane; enough to make one ATP, and since photons are free, life must suddenly have been released from dependence on inorganic nutrients synthesis: with photosynthesis! Suddenly there was enough ATP to generate nutrients from simple chemicals like carbon dioxide and ammonia!!! There are still bacteria that employ only cyclic photosynthesis.

There still wasn’t enough ATP available to store large supplies of sugars and starches to give evolution a much needed boost so nature invented the noncyclic process which created eight times more ATP than the cyclic process. In that process the electron energy is boosted in two steps, and so much extra charging and other work is wrung from its energy that eight ATP’s can be made from two activated electrons because the electron is not returned to the chlorophyll but is handed to an energy-storage molecule instead; the missing electron is obtained by splitting water, which generates oxygen as a waste product.
To put it another way, the electron end up in a multipurpose energy compound that can be used directly to power carbon fixation to charge the membrane for subsequent ATP production. The missing electron in the first chlorophyll is replaced with one obtained by splitting water, a process that liberates oxygen.
Most photoautotrophs (all true plants) use the more efficient noncyclic process with the eight-fold increase in energy production.
Because eight times more ATP was being produced by all the plants they were able to create more energy storage in the form of carbon-based, starches and sugars. The noncyclic process not only created more free oxygen it also allowed millions of other life forms to evolve to feed on the extra, eight-fold energy created by this process. This is why we have coal, oil and limestone on Earth plus myriads of other oxygen-breathing animals like Hillary Clinton.

--The Assembly of Cell Membranes by Mark S. Bretscher; Scientific American, October 1985
--The Photosynthetic Membrane by By Kenneth R. Miller Scientific American, October 1979
--Molecular Mechanisms of Photosynthesis by Douglas C Youvan and Barry L. Marrs; Scientific American, June 1984
--Cytochrome C and the Evolution of Energy Metabolism, by Richard E. Dickerson, Scientific American, March 1980 Offprint 146
Me: Captain Hank Kroll

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