On the Origins of Life

Commentary ^ | February 2006 | David Berlinski

[grey_whiskers]

Please see my prior post to Vade Retro (courtesy ping and all that, as you so graciously instructed me to do). I tried to type your name in, and inadventently put in your initials instead :-(

[hosepipe]

Amino Acids that can replicate themselves is/are a;
Perpetual Motion Machine.. Is that possible?..

[csense]

Except that evolution does not depend on any particular process for the origin of life, evolution would occur just the same regardless.

It does if the origin of life corresponds to one of the major world religions, and most, if not all, of the minor ones.

To say that Christianity, Judaism, and Islam are compatible with evolution is simply to be ignorant of what these texts teach....however wishful and compromising your thinking may be.

Those of us who consider logic and reason to be a beneficial attritbute of the human condition, do not agree with your inference that evolution is compatible with all possible scenarios. Such thinking just reinforces the observation that evolution is an unfalsifiable concept...and it does nothing to garner intellectual respect from those who should be your audience.

That you believe evolution to have occured is implicit from your writings. That evolution must necessarily occur, is simply not dictated by logic.

[spunkets]

"more chemically reactive. A different way in which light might affect populations of enantiomers."

Considering that only single bonds can be excited, and excitation of those bonds doesn't depend on the optical rotation of incident light, there can be no effect.

[spunkets]

" I did mention racemization."

I don't know where that post was, but racemization requires bond breaking.

[grey_whiskers]

and excitation of those bonds doesn't depend on the optical rotation of incident light, there can be no effect.

Ahh, *that* part I missed. Thanks!

[grey_whiskers]

The problem is that Berlinski has assumed the mantle of someone qualified to review where we are, but he would appear not to know anything about the evidence inconvenient to the agenda of the un-Discovery Institute of which he is a fellow.

I never heard of the Discovery Institute outside of these threads. Are they perhaps in general rather late at catching up to things? Oh--I get it--they are so late, so often, that you think it is *deliberate*. Like some of the more (in)famous crevo posters here.

Cheers!

[furball4paws]

Optical rotation is quite complex and is affected by pH and concentration. In addition, the pK of groups like sulfhydryl groups affect the rotation. A big pH change can even shift one from a + rotation to a - rotation.

Here are the rotations, usually at 20 C, but the concentrations and pHs vary because of solubilities:

L-ala +2.8
L-arg +26.9
L-asp +25
L-asn -5.4
L-cys +13
L-cystine -223.4
L-met -8.2
L-glu +31
L-gln +6.1
L-pro -52.6
L-leu -10.8
L-lys +25.9
L-his -39.7
L-thr -28.3
L-ile +11.3
L-val +13.9
L-ser -6.8
L-trp -31.5
L-tyr -10.6
L-phe -35
L-hydroxyproline -76.5
L-ornithine +11.5
L-citrulline +3.7

achiral: glycine, beta-alanine

I'm sure I missed some - list from Merck Index.

[furball4paws]

should have pinged you guys too.

[muir_redwoods]

The spell checker performed a 'random mutation' on what I had typed in. Darwin would be proud of it.

Darwin would have researched it further

[furball4paws]

Enzymatically converted - yes, but not post translation. The peptidoglycan is not a translated protein.

[spunkets]

You're welcome.

I don't think these biological molecules came from space anyway. I think the L amino acids are the only ones that have a significant interaction with RNA triplets, as per RWP's post above. I haven't looked at it, so it's quicker to ask RWP if that's so. RWP?

[VadeRetro]

My only question is whether Berlinski is in fact merely *ignorant* of recent developments--see my remark about his assuming the threshold of his ignorance, and how he thinks it is the same as everyone else's.

I invite the lurker to look at the article Berlinski wrote, a supposed survey of the current status of abiogenesis research, and ask himself whether Behe should have known of this link (or at least the various article footnoted therein) or, if not this link (admittedly local in origin, at least the papers cited therein, specifically:

But if you want geochemical differences in precambrian rocks that indicate the presence of a reducing atmosphere, see for example Geological and trace element evidence for a marine sedimentary environment of deposition and biogenicity of 3.45 Ga stromatolitic carbonates in the Pilbara Craton, and support for a reducing Archaean ocean (2003) by Van Kranendonk, Webb, and Kamber. Excerpt from the abstract:

The geochemical results, together with sedimentological data, strongly support: (1) deposition of Dresser Formation and Strelley Pool Chert carbonates from Archaean seawater, in part as particulate carbonate sediment; (2) biogenicity of the stromatolitic carbonates; (3) a reducing Archaean atmosphere; (4) ongoing extensive terrestrial erosion prior to 3.45 Ga.

A "reducing atmosphere", for those in Rio Linda, is "An atmosphere of a planet or moon which has a high hydrogen content, either in the form of free hydrogen or hydrogen-containing compounds, such as methane or ammonia", according to the Encyclopedia of Astrobiology, Astronomy, and Spaceflight.

Berlinski should know this. He in effect claims not to. But what he conveniently does not know seriously undercuts his premise and he has no business writing the lead article of this thread without knowing the actual state of the evidence for a reducing atmosphere. How does that rate a big *sigh* over my pointing this out? Why is the bar set so low for the Holy Warriors of the un-Discovery Institute?

[furball4paws]

The racemization of L-ala takes place in the periplasm in E. coli which makes sense. I presume it is also outside the membrane in Gram positives.

[edsheppa]

D and L (or S and R) have nothing to do with the rotation of polarized light (+ or -), they are simply based on standardized structures.

That wasn't really the point I was making. I may be wrong (and I'm sure S will correct me if I've got it wrong) but, as I understand it, S is arguing against the notion that polarized light can destroy different isomers at different rates. S says that only the interaction of the light with the individual bonds is important and, because the molecules are randomly oriented to the light, the light won't be able to tell the difference.

I think that argument is suspect because solutions of molecules homogenous in chirality do interact differently depending on polarization.

[Ken H]

I hold in my hand a bottle of L-Arginine which I purchased upon the written recommendation of the late Dr. Atkins (in one of his Atkins Diet books, as an aid to more restful sleep.

You mean I done been flim-flammed on this purchase? :-)

As long as you sleep on your right side, it should work fine:)

[VadeRetro]

... whether Behe should have known...

Those Killer Bs, they got me this time! Berlinski is at issue here.

[furball4paws]

The photodestruction of a compound is going to depend mostly on the light intensity and the wavelength. RWP may have something to add here.

[spunkets]

"I think that argument is suspect because solutions of molecules homogenous in chirality do interact differently depending on polarization."

It's the configuration that causes that, not the dielectric response causing rotation.

[edsheppa]

The photodestruction of a compound is going to depend mostly on the light intensity and the wavelength.

I think you mean wavelength only - the intensity would affect the rate but it's the frequency that selects the interaction.

Again, it seems to me that photodestruction is simply one kind of interaction if light and matter and that if another interaction depends on chirality then perhaps photodestruction can too in the right circumstances.

Of course I'm seriously out of my depth here :-)