New Oxygen research;early electron release in photosynthesis (Introduction)

by David Turell , Monday, April 03, 2023, 15:17 (600 days ago) @ David Turell

Electrons are released much earlier than thought:

https://www.livescience.com/scientists-accidentally-discover-photosynthesis-doesnt-work...

"In the new study, published March 22 in the journal Nature(opens in new tab), researchers used a new technique, known as ultrafast transient absorption spectroscopy, to study how photosynthesis works at a timescale of one quadrillionth of a second (0.000000000000001 second) for the first time. The team was initially trying to figure out how quinones — ring-shaped molecules that can steal electrons during chemical processes — impact photosynthesis. But instead, the researchers found that electrons could be released from photosystems much earlier during photosynthesis than scientists previously believed was possible.

***

"Two photosystems are used during photosynthesis: photosystem I (PSI) and photosystem II (PSII). PSII primarily provide electrons to PSI by taking them from water molecules: PSI then further excites the electrons before releasing them to eventually be given to carbon dioxide to create sugars, via a series of complex steps.

"Past research had suggested that the protein scaffolding in PSI and PSII was very thick, which helped to contain electrons within them before being passed on to where they were needed. But the new ultrafast spectroscopy technique revealed that the protein scaffolding was more "leaky" than expected and that some electrons could escape from the photosystems almost immediately after light was absorbed by the chlorophyll within the photosystems. These electrons could therefore reach their destinations faster than expected.

***

"'Many scientists have tried to extract electrons from an earlier point in photosynthesis, but said it wasn't possible because the energy is so buried in the protein scaffold," Zhang said. "The fact that we can [potentially] steal them at an earlier process is mind-blowing.'"

Comment: Such a complex system cannot happen by chance. Design required.