Biological complexity: photosynthesis controls (Introduction)

by David Turell , Wednesday, December 21, 2022, 21:45 (492 days ago) @ David Turell

More parts unearthed:

https://phys.org/news/2022-12-decoding-secret-language-photosynthesis.html

"For half a century botanists have known that the command center of a plant cell, the nucleus, sends instructions to other parts of the cell, compelling them to move forward with photosynthesis. These instructions come in the form of proteins, and without them, plants won't turn green or grow.

"'Our challenge was that the nucleus encodes hundreds of proteins containing building blocks for the smaller organelles. Determining which ones are the signal to them to trigger photosynthesis was like finding needles in a haystack," said UCR botany professor Meng Chen.

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"'The conductors of the symphony are proteins in the nucleus called photoreceptors that respond to light. We showed in this paper that both red and blue light-sensitive photoreceptors initiate the symphony. They activate genes that encode the building blocks of photosynthesis."

"The unique situation, in this case, is that the symphony is performed in two "rooms" in the cell, by both local (nucleus) and remote musicians. As such, the conductors (photoreceptors), who are present only in the nucleus, must send the remotely located musicians some messages over distance. This last step is controlled by the four newly discovered proteins that travel from the nucleus to the chloroplasts.

***

"Currently, a lot of research describes communication from organelles back to the nucleus. If something is wrong with the organelles, they'll send signals to the nucleus "headquarters." Much less is known about the activity-regulating signals sent from the nucleus to the organelles.

"'The nucleus may control the expression of mitochondrial and chloroplast genes in a similar fashion," said Chen. "So, the principles we learn from the nucleus-to-chloroplast communication pathway might further our understanding of how the nucleus regulates mitochondrial genes, and their dysfunction in cancer," Chen said."

Comment: this is another example of a system that must appear all at once to function. It is irreducible complex and must be designed in toto.