July 21, 2014 | David F. Coppedge

Secrets of Photosynthesis Coming to Light

“It’s perhaps the most important biochemical process on Earth and scientists don’t yet fully understand how it works.”

It’s in the vibes:  Scientists at University of Michigan have used extremely brief pulses of light to study molecular vibrations that enhance the light-gathering ability in the chloroplasts of plants—specifically, in the antenna complex called Photosystem II that does the “heavy lifting” of photosynthesis.  Enzymes in this complex kick electrons out of molecules as the first step in energy transfer.  Science Daily says that irradiating spinach leaves in a blender with ultrashort pulses revealed these vibrations that take place faster than one hundredth of a billionth of the blink of an eye.

Through photosynthesis, plants and some bacteria turn sunlight, water and carbon dioxide into food for themselves and oxygen for animals to breathe. It’s perhaps the most important biochemical process on Earth and scientists don’t yet fully understand how it works.

The researchers likened the vibrations to the activity of a bucket brigade.  When all the workers are in sync, the maximum amount of water can be transferred.  With this knowledge, researchers hope to reverse engineer photosynthesis, “to design materials that have appropriate vibrational and electronic structure to mimic this highly efficient charge separation process.

It’s in the traps:  Researchers at Arizona State also irradiated Photosystem II with light pulses and found that the enzymes open up and grab water molecules during the energy transfer, according to Science Daily.  To see this in action, they had to use light pulses lasting only one quadrillionth of a second (a femtosecond, 10-15 second).  Watching the response, they saw the enzyme elongate allowing water to enter.  “This is a major step toward the goal of making a movie of the molecular machine responsible for photosynthesis, the process by which plants make the oxygen we breathe, from sunlight and water,” one researcher said.  Like the team in Michigan, the Arizonans are looking to apply what they learn to improve photocells.

It’s in the maintenance:  Another article about Photosystem II on PhysOrg tells about the quality control system in the machinery.  Deep in the thylakoid membranes that make up the grana of chloroplasts, there are specialized enzymes that can remove receptors that have become damaged by strong light, and replace them by newly-synthesized parts.  Researchers at Okoyama University in Japan found that the grana become “unstacked” in order for the FtsH proteases to enter the damage site and make repairs.  “This maintenance system keeps photosynthetic activity under light stress.”

When the older among us were going to school, photosynthesis was a “black box” that was only crudely understood.  Light photons entered the black box, and sugar came out.  In the last few decades of research, just the barest outlines of the process have been coming to light.  Who would have known that there is quality control, synchronized vibration, and moving parts?  This is intelligent design on a quantum scale.  Yet the second article makes this stupid statement: “The early Earth contained no oxygen and was converted to the oxygen-rich atmosphere we have today 2.5 billion years ago by the ‘invention’ of the water splitting process in Photosystem II (PSII).”  No scientist ever experienced a thousand years, let alone 2.5 billion years.  And who, pray tell, “invented” this elegant molecular machine?  Natural selection?  Fat chance.  Chance is too fat to do such things.  It’s so fat it can’t budge.  Slim down into the sleek, functional intelligent design athletic wear so that you can think rationally.

 

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