Introducing the eye (Introduction)

by David Turell @, Monday, January 03, 2022, 22:50 (17 days ago) @ David Turell

Seeing faint light:

https://www.sciencedaily.com/releases/2022/01/220103121742.htm

"PSI scientists have shed light on an important component of the eye: a protein in the rod cells of the retina which helps us see in dim light. Acting as an ion channel in the cell membrane, the protein is responsible for relaying the optical signal from the eye to the brain.

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"'It's thanks to the rod cells in our eye that we can observe the stars in the night sky," explains Jacopo Marino, a biologist with PSI's Laboratory of Biomolecular Research. "These photo cells are so sensitive to light that they can detect even a single photon reaching us from a very remote part of the universe -- a truly incredible feat." The ability of our brain to eventually translate these light beams into a visual impression is partly down to the cyclic nucleotide-gated (CNG) ion channels whose three-dimensional structure has now been illuminated by a PSI research group led by Jacopo Marino.

"The ion channel acts as a gatekeeper controlling whether specific particles are allowed through to the interior of the receptor cell. It is embedded in the protein-rich shell -- the cell membrane -- of the rod cells. In darkness, the ion channel, and thus the gate to the cell, is completely open. But when light hits the eye, it triggers a cascade of processes in the rod cells. This ultimately causes the gate to close, with the result that positively charged particles, such as calcium ions, can no longer enter into the cell.

"This electrochemical signal continues via the nerve cells into the brain's visual cortex, where a visual impression -- such as a flash of light -- is created.

***

"The protein comprises four parts: three lots of subunit A, and one lot of subunit B. A correctly functioning ion channel is only possible in this combination. In their study, PSI scientists show why the B subunit seems to play such an important role: a side arm of the protein -- a single amino acid -- protrudes from the rest of the protein, like a barrier across a gateway. This narrows the passage in the channel to the point where no ions can pass through.

"'No one expected that -- it came as a total surprise," says Diane Barret. Other narrow places already exist in the A subunit -- like main gateways -- which were previously thought to be the only ones. It is interesting to note that the additional barrier is found not only in the protein from the cow's eye, but seems to apply to all types of animal, as the scientists showed. Whether crocodiles, eagles or humans -- all living creatures with an ion channel in their eye have the same protruding amino acid at this position in the protein. As it has been preserved so consistently during evolution, it must be essential for the functioning of the channel."

Comment: The fact that it is conserved shows the detail of design in stepwise fashion by God. It seems the disparaged backward human retina by Darwinists has received perfect results in design from past stages.


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