Biological complexity: photosynthesis controls overload (Introduction)

by David Turell , Thursday, June 25, 2020, 19:37 (1394 days ago) @ David Turell

Too much energy can damage cells:

https://phys.org/news/2020-06-green-team-photosynthesis.html

"When sunlight shining on a leaf changes rapidly, plants must protect themselves from the ensuing sudden surges of solar energy. To cope with these changes, photosynthetic organisms—from plants to bacteria—have developed numerous tactics.

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"'Our model shows that by absorbing only very specific colors of light, photosynthetic organisms may automatically protect themselves against sudden changes—or 'noise'—in solar energy, resulting in remarkably efficient power conversion," said Gabor, an associate professor of physics and astronomy, who led the study appearing today in the journal Science. "Green plants appear green and purple bacteria appear purple because only specific regions of the spectrum from which they absorb are suited for protection against rapidly changing solar energy."

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"'Excitingly, we were then able to show that the model worked in other photosynthetic organisms besides green plants, and that the model identified a general and fundamental property of photosynthetic light harvesting," he said. "Our study shows how, by choosing where you absorb solar energy in relation to the incident solar spectrum, you can minimize the noise on the output—information that can be used to enhance the performance of solar cells."

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"Gabor explained that plants and other photosynthetic organisms have a wide variety of tactics to prevent damage due to overexposure to the sun, ranging from molecular mechanisms of energy release to physical movement of the leaf to track the sun. Plants have even developed effective protection against UV light, just as in sunscreen.

"'In the complex process of photosynthesis, it is clear that protecting the organism from overexposure is the driving factor in successful energy production, and this is the inspiration we used to develop our model," he said. "Our model incorporates relatively simple physics, yet it is consistent with a vast set of observations in biology. This is remarkably rare. If our model holds up to continued experiments, we may find even more agreement between theory and observations, giving rich insight into the inner workings of nature.'"

Comment: Very clever design. Not by chance