Re: basic question about light


"Randy Poe" <poespam-trap@xxxxxxxxx> wrote in message news:1171053126.683153.265140@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Feb 9, 2:57 pm, "Androcles" <Engin...@xxxxxxxxxxxxxxxxxxxxxx>
wrote:
"Randy Poe" <poespam-t...@xxxxxxxxx> wrote in messagenews:1171023849.729057.285510@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Feb 8, 5:24 pm, "Androcles" <Engin...@xxxxxxxxxxxxxxxxxxxxxx>
wrote:
"Randy Poe" <poespam-t...@xxxxxxxxx> wrote in messagenews:1170952542.670726.97310@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
[A photon] is absorbed by a pigment molecule in your retina.

Are TV signals absorbed by aluminium molecules in the antenna?

Biological and man-made systems use different strategies. Visual
pigments are not conductors. Their electrons are bound to them,
not free as in an antenna.
Here's a partial description of the transduction process:
(fromhttp://webvision.med.utah.edu/photo1.html)

"Upon absorption of a photon of light, the retinal isomerizes from
the 11-cis form to an all-trans form which starts conformational
changes in the molecule resulting in bleaching. Several intermediaries
are formed in bleaching among them metarhodopsin II which activates
the G-protein transducin and a further cascade of events summarized
below (see review by Hargrave and McDowell (1992) and by Archer,
1995).
"Light transduces the visual pigment via the following enzyme
cascade:
photons - rhodopsin - activated rhodopsin (metarhodopsin II) - a GTP
binding protein (transducin) - an enzyme hydrolyzing cGMP
(cGMP-phosphodiesterase) - closes a membrane bound cGMP-gated
cation channel."

utah.edu, huh? The mormon home of cold fusion, wasn't it?

No, this is the med school.

Oh, ok. Well done. This is a physics newsgroup.
Are TV signals absorbed by aluminium molecules in the antenna?



Thanks for the word soup, I'm sure it would have been all very
interesting if I'd bothered to read it.

I know you have attention-span problems.

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?

I was hoping you saw enough to point out that what I said was correct: a photon
is absorbed by a visual pigment, initiating a set of chemical
reactions.

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?



Let me highlight the relevant part without straining your attention
span:

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?


"Upon absorption of a photon of light, the retinal..."

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?




Got that?


No, but are TV signals absorbed by aluminium molecules in the antenna?



The molecule absorbed a photon.

"... isomerizes from the 11-cis form to an all-trans form"

Got that? The effect was to change the shape of the
molecule. I won't strain you by going farther.

You don't like utah.edu.

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?



Fine, let's look elsewhere:
http://www.biologymad.com/NervousSystem/eyenotes.htm
"In the dark retinal is in the cis form, but when it absorbs a photon
of light it quickly switches to the trans form. This changes its
shape..."

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?



Got that? "absorbs a photon"? "changes its shape"?

No, but are TV signals absorbed by aluminium molecules in the antenna?

Want to see another?

No, but are TV signals absorbed by aluminium molecules in the antenna?


http://www.math.utk.edu/~vasili/va/descr/phototrans/
Doesn't have a writeup. Instead refers to the Utah writeup as a
"spectacular link".

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?


Another?

No, but are TV signals absorbed by aluminium molecules in the antenna?


http://www.ch.ic.ac.uk/vchemlib/mim/bristol/retinal/retinal_text.htm
"When a photon of light falls onto rhodopsin, the molecule absorbs the
energy..."

Got that? The molecule absorbs the photon.

No, but are TV signals absorbed by aluminium molecules in the antenna?



"...and the cis-double-bond between C-11 and C-12 in the retinal is
temporarily converted into a single bond. This means the molecule can
now
rotate around this bond, which it does by swivelling through 180°."

Sorry, too many big words for you. I lost you. That's OK, we'll just
skip
ahead a sentence or two to where it uses short words again

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?



"... it changed the shape of the retinal from curved to straight.
Essentially,
the energy in a photon has been converted into atomic motion."

Got that? Changed the shape.

No, but are TV signals absorbed by aluminium molecules in the antenna?



These chemical transducers are pretty cool, actually. It's too bad
you don't believe in them.

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?



I hope you'll agree that "isomerizing resulting in bleaching" or "an
enzyme cascade" is not a description of anything that happens in
an aluminum antenna upon absorption of a photon. It is, however,
what happens in your eye.

I hope you'll agree that antennae come in different sizes, with
giraffementhttp://www.mccullagh.org/db9/10d-17/giraffe-1.jpg

Yes they do, but visual pigments (sorry, you don't understand that)
I mean visual MOLECULES are not antennas.

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?



to shrewment
http://www.taiga.net/wmac/consandmanagementplan_volume3/graphics/phot...

molecules with pigment
http://www.snoopy.com/comics/peanuts/meet_the_gang/images/meet_pig_pe...

Do you not know what "pigment" means?
Yeah, but are TV signals absorbed by aluminium molecules in the antenna?



molecules
somewhere in the middle to do the photon absorbing, but you
didn't answer my question, Blind Poe. Please note the word
"basic" in the thread title.

Which part of :
"Are
TV
signals
absorbed
by
aluminium
molecules
in
the
antenna?"
did you not understand?

I always have to slow things down for you, don't I?

Yeah, but are TV signals absorbed by aluminium molecules in the antenna?



The answer is: No. TV signals are not absorbed by Al
molecules in an antenna.

Ok, we got there at last. So... what does absorb TV signals in an antenna?


The followup is: That has nothing to do with the question
of how visual pigments work, since visual pigments are
not aluminum antennas.

Does that help?
No, but you are very good at saying what things are not, I congratulate
you.
I'm very pleased to discover that pigments are not aluminum antennae,
although I have to tell you I knew that.
Did you know that copper wire is not an aluminium antenna?

Please answer the question, I'll repeat it slowly for you.
What
DOES
absorb
TV
signals
in
an
antenna?

.

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