Surely, evidence of everything alive (especially humans) supports Darwin's theory?

[Mr Skeptic]

You can make your own. It's very simple. Here's the recipe:

Call Sigma Chemical Co. at 800-325-3010 and order 1 bottle of catalog number M 7145 and one bottle of R 7131 amino acids solutions (you need both to get all the amino acids http://www.sigmaaldrich.com/sigma/formulation/M5550for.pdf ). They will cost you about $40 plus shipping for both. Empty the bottles into a fying pan, turn the heat on low and heat until all the water is evaporated. Then heat for 20 more minutes. Add water.

 

You can then add more amino acids, some ATP, and some sugars if you want. However, it turns out that some of the protocells are photosynthetic.

 

You are going to have a minor problem: bacterial contamination. Bacteria are everywhere and, if you leave the protocell solution sitting out for even a couple of minutes, bacteria from the air, your spoon, etc, is going to get into the solution and these bacteria will, in about a day, eat the protocells. So, do you have a laminar flow hood and some culture dishes?

 

But I want to grow a colony from one of yours, not make my own. I have no idea what properties mine would have. Couldn't you send me some of your photosynthetic ones so I could grow a whole colony of photosynthetic protocells? That would be so cool. And yes, I am familiar with aseptic technique. I don't have a flow hood but I have usually been able to avoid contamination by leaving things uncovered for a minimum time.

[lucaspa]

You need to take a better look at what you’re saying. I don’t even know what you mean by “non-living chemicals.” Is RNA a non-living chemical? Is NaCl a non-living chemical? I’d say both are non-living chemicals, including DNA.

 

Then we don't have a problem. IF you would have read the websites (did you? It appears not.) then you know we aren't even starting with RNA or DNA or proteins. The starting chemicals are amino acids, the precursors to proteins.

 

If you know of a living system that gets along in life without genetic information I’d love to hear about it.

 

I'm telling you about one! Read the websites! Protocells do not have a genetic system but they do have, in a fashion, a system of inheritance.

 

 

OK, I’ll assume from what you say that the “needed” proteins can be made directly with AAs and heat. But that doesn’t get you abiogenesis from scratch.

 

If you then add water to the proteins, that does get you abiogenesis from scratch. Read the websites! Directed protein synthesis comes later. The protocells make RNA and DNA from nucleotides.

 

Reproduce what? You’ve haven’t even addressed the need for the emergence of a digital genetic code.

 

Themselves. New protocells. There is no need of a genetic code to have life. That comes later. By division, the protocells do pass on their materials to their progeny.

 

You cannot have abiogenesis until you have a cell with the ability to pass on its genetic material to its progeny.

 

That's your strawman. Being alive only calls for reproduction. It doesn't call for "genetic material". That's your fixation: that you think you have to have DNA/RNA and directed protein synthesis from the beginning. You don't. They can come later after you have living cells. See the quotes at the end of the post.

 

I’m astonished that one in your position would say this. If what you say is true then please show the evidence that those little gene-less critters actually did pop out as the “bottom line.”

 

Read the websites! Part of the evidence is there. After you have read the websites, I'll direct you to some peer-reviewed articles in the scientific literature.

 

I’m still wondering how you can get “reproduction” in life without being concerned about genetic inheritance. Do your “protocells” just sort get their genetic information by osmosis?

 

LOL! The protocells divide. Like bacteria. Each daughter cell gets half the material of the original. Then they too grow in size until the point that they, too, fission. Read the website. It's all there if you would have taken the time to look at the data.

 

This statement is unbecoming of a “Biology Expert Moderator.” How can you refute my claim of being an untheist? Who would know better than I?

 

People can mislabel themselves. You can start by addressing the issues I raised. Why is it that you are objecting so much to any suggestion of life arising by simple chemistry? Resisting to the point that you won't even look at the sources given you.

 

Suggesting that I am a creationist is shameful, worthy of suspension.

 

If it walks like a duck and quacks like a duck .... Saying abiogenesis is impossible is one of the major arguments and claims of creationism. I think you'd better look in the mirror before you throw around the charge of "insecure". Why haven't you read the websites I posted? If you had, you wouldn't have posted this silly post, because all the answers were there.

 

"Self-forming, cell-like structures ... have been described, in great detail, by Fox. These remarkable bodies arise spontaneously wehn hot concentrated solutions of thermally formed proteinoids are allowed to cool .... Microspheres show several types of cell-like behavior. They can be induced to undergo cleavage or division by suitable changes in pH or when exposed to MgCl2. ... They can also be shown to accelerate chemical reactions when formed from proteinoids having catalytic activity ...

In more recent work, Fox and his colleagues have shown that basic proteinoids, rich in lysine residues, selectively associate with the homopolynucleotides poly C and poly U but not with poly A or poly G. On the other hand, arginine-rich proteinoids associate selectively with poly A and poly G. In this manner, the information in proteinoids can be used to select polynucleotides. Morever, it is striking that aminoacyl adenylates yield oligopeptides when incubated with proteinoid-polynucleotide complexes, which thus have some of the characteristics of ribosomes. Fox has suggested that proteinoids bearing this sort of primitive chemical information could have transferred it to a primitive nucleic acid; the specificity of interaction between certain proteinoids and polynucleotides suggests the beginning of the genetic code." A. Lehninger, Biochemistry, 1975, pp 1047-1048

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But I want to grow a colony from one of yours, not make my own. I have no idea what properties mine would have.

 

The literature on protocells (sometimes called "microspheres") is quite extensive. They all have the same properties; the properties are not dependent on colonies. So if you make your own they will be like all those in the literature.

 

I don't have a colony of them right now. I made a batch just to see that I could, if I followed the protocol in the literature. Do you think the protocol I have laid out is too complicated for you to follow?

 

And yes, I am familiar with aseptic technique. I don't have a flow hood but I have usually been able to avoid contamination by leaving things uncovered for a minimum time.

 

Really? I'm a bit skeptical since I have seen people, even using dead air hoods, have a pretty high rate of contamination. But hey! That's a problem of contamination and technique, not the cells. So go for it. I would use standard culture media, probably CMRL 1066 or BGJ. Or you could use bacterial agar. Have fun. BTW, if you use culture media, then changing media is going to be a bit difficult, since the protocells are the size of bacteria and don't adhere to the culture dish. It's like dealing with suspension cultures. But you sound like you think you know what you are doing.

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Furthermore, I don't think panspermia helps as much as you'd think.

 

I don't think it helps at all. It simply pushes the problem to someplace else (sometimes called "begging the question"). That life off earth had to come from somewhere. Where? Where did life arise if not on earth? How did life arise in this other place? Chemistry? Manufacture by aliens? If the latter, how did the aliens arise? If Scrappy doesn't think the genetic code could have arisen by chemistry and biology on earth, why would he think it could arise someplace else?

 

Somewhere you still face the issue of abiogenesis: life arising by chemistry.

 

Given that early Earth wasn't a homogenous mass, you could probably find some or many of the 'extraterrestrial' conditions here, such as under ice or near deep-sea vents.

 

Good point. The earth has some extreme environments, about as extreme as they can be and still have liquid water.

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Thank you for pointing out my hang ups. And you are quite right: I am terribly hung up about the need for a digital genetic code to arise (however mysteriously) in the course of any abiogenesis event.

 

That's your misconception. You don't have to have a genetic code at an abiogenesis event. Directed protein synthesis can come later and evolve.

 

Your little “prebionts” in their lipid bubbles, how do they accomplish reproduction without a genetic language? Just simply duplicating themselves in chemical composition is not enough; calcite crystals can do that.

 

No, division is sufficient. You don't have to have "coded instructions". All you have to have are the elements that allow the progeny to by alive. Elements for metabolism, response to stimuli, growth, and let the progeny themselves reproduce. "Coded instructions" can come later.

[scrappy]

That's your misconception. You don't have to have a genetic code at an abiogenesis event. Directed protein synthesis can come later and evolve..."Coded instructions" can come later.

lucaspa, you are misinformed on what it takes to be biologically alive. To be biologically alive, your prebioants (which is exactly what they are) must be subject to natural selection. You are talking about prebioants that no doubt appeared as pre-biotic superstructures and housekeeping parts: protocells, protoproteins and other protochemicals that were needed to be assembled somehow for that splendid event of abiogenesis to occur. Sure, your protocells can make copies of themselves, but that's only a function of physical analogues, much the same way crystals "reproduce" themselves. Whatever they were, those protocells, they were non-living chemicals—biologically non-living, that is—and probably extremely rare. But they had to occur somewhere, sometime, somehow, so we let the imagined components of that “primordial soup,” prebioants and all, stand in for what we don’t know yet about that splendid moment (or moments?) when biological life kicked in and Darwinian evolution took over.

 

I am talking about what was necessary for that splendid moment to occur—the one when a genetic language kicked in and those prebiotic protocells took on the job of genetic inheritance. That's when biological life began; that's when abiogenesis occurred.

 

Please consider this from A. G. Cairns-Smith’s Seven Clues to the Origin of Life (1985, pp. 114-116):

 

“First clue: Genetic information is the only thing that can evolve through natural selection because it is the only thing that passes between generations over time...”

 

Now, he also mentions a fifth clue:

 

“Fifth clue: Primitive machinery is usually different in its design approach (and hence materials of construction) from the later advanced counterparts…”

 

I agree, of course, and that primitive machinery is exactly what he says it is: “primitive machinery.”

 

As such, all biologically living things owe a debt of gratitude to your prebioants, but however splendid they are they don't represent what happened when abiogenesis became a reality.

[Mr Skeptic]

They can be induced to undergo cleavage or division by suitable changes in pH or when exposed to MgCl2.

 

Wait, isn't that cheating just a bit? We need to induce cleavage?

 

The literature on protocells (sometimes called "microspheres") is quite extensive. They all have the same properties; the properties are not dependent on colonies. So if you make your own they will be like all those in the literature.

 

I thought you said that some of them are photosynthetic. Are all of them photosynthetic?

 

I don't have a colony of them right now. I made a batch just to see that I could, if I followed the protocol in the literature. Do you think the protocol I have laid out is too complicated for you to follow?

 

No, the protocol is quite simple, but as I said I don't want to make my own. I want to grow a colony of them from a sample of protocells, especially ones with interesting properties. You know, like culturing strains of bacteria?

 

Really? I'm a bit skeptical since I have seen people, even using dead air hoods, have a pretty high rate of contamination. But hey! That's a problem of contamination and technique, not the cells. So go for it. I would use standard culture media, probably CMRL 1066 or BGJ. Or you could use bacterial agar. Have fun. BTW, if you use culture media, then changing media is going to be a bit difficult, since the protocells are the size of bacteria and don't adhere to the culture dish. It's like dealing with suspension cultures. But you sound like you think you know what you are doing.

 

Well yes, this is done in undergraduate level biology classes. Probably some high schools too. Eg for teaching aseptic technique, they have you inoculate a plate with distilled water. If something grows, you did it wrong (or were unlucky). Most were successful. Of course, if you are running an expensive experiment, you don't want to rely on luck for a bacteria not to fall onto your plate, so you really do want a hood. Also, if your procedure takes a lot of time, that is just that much likelier for something to fall in.

[cameron marical]

what do cells live off of exactly?

 

i know this is a little of topic, but this q has been bugging me for a while.

 

also, is there anything other than cells that viruses and reproduce and feed off of?\

 

thank you.

[CharonY]

make RNA and DNA from nucleotides

.

Are you referring to flavoprotenoid microspheres or about lipid protocells?

I only recall the Szostak paper on this point and AFAIK their point was mostly that their lipid protocells allow diffusion of nucleotids and that the lipid environment of the cell is compatible with simple chemical primer extension reactions.

In flavoprotenoid microsphores ATP generation was found but essentially it was due to irradiation of ADP in presence of Pi (which is quite intersting by itself, though), but I have not yet heard about real photosynthesis.

Could you provide a source for that ? I only recall that at some point someone assmebled a protocell and added some porphyrins. But I would by surprised if that led to photosynthesis.

 

And why precisely would one need a culture medium for them? I may be missing something but they do not have metabolism and hence should be pretty stable in a defined buffer. Am I missing something here?

 

And just btw. in theory for pure sterile work a clean, turbulence free horizontal flow box would be ideal. Dead flow do not provide active protection (though they reduce turbulence). It tends to be more necessary for smaller contaminants (as e.g. DNA), which are not removed by HEPA filters.

But that being said, if you are practiced enough for a limited number of samples it can be enough just to work near a flame. Many microbiologists do that.

[lucaspa]

lucaspa, you are misinformed on what it takes to be biologically alive. To be biologically alive, your prebioants (which is exactly what they are) must be subject to natural selection.

 

That's not part of the definition of "life". But, as it happens, the protocells I'm talking about (did you read the websites?) are subject to natural selection:

 

"The ease with which such protocell units arise under possible primitive Earth conditions has been abundantly documented, especially in the elegant experiments of Sidney Fox and his collaborators on the proteinoid microspheres. .. For our purposes it is sufficient to note that preformed primitive polypeptides (proteinoids) have properties enabling them to aggregate spontaneously to form remarkably uniform spherical units of bacterial dimensions which contain complex internal morphology including a double wall, exchange materials with the ambient medium, grow, cleave in two, fuse, exhibit weak catalytic activiity, and move when ATP is added to the medium. Protocells containing both proteinoid and polynucleotide have been shown to carry on a primitive kind of protocoding activity (27,29) The proteinoid microsphere is a compelling model for the high-probability prebiotic origin of discrete individual units of evolving organic mattter which could conceivably compete with one another and thus provide the basis for a primitive selection process." Dean H. Kenyon, Prefigured ordering and protoselection in the origin of life. In The Origins of Life and Evolutionary Biochemistry, ed. Dose, Fox, Deborin, and Pavlovskaya, 1974, pg 211.

 

Whatever they were, those protocells, they were non-living chemicals—biologically non-living, that is—and probably extremely rare.

 

Wrong on both counts. The protocells would be living. To be alive, an entity must have all 4 of the following characteristics:

1. metabolize (have anabolism and catabolism)

2. Grow

3. Respond to stimuli

4. Reproduce.

 

Crystals grow, but they don't do the other 3. Protocells do all 4. They are that "magical moment" when life began and Darwinian evolution started.

 

I am talking about what was necessary for that splendid moment to occur—the one when a genetic language kicked in and those prebiotic protocells took on the job of genetic inheritance. That's when biological life began; that's when abiogenesis occurred.

 

Strawman. Genetic inheritance is not needed to be alive. Abiogenesis happens before the beginnings of genetic inheritance.

 

Please consider this from A. G. Cairns-Smith’s Seven Clues to the Origin of Life (1985, pp. 114-116):

 

“First clue: Genetic information is the only thing that can evolve through natural selection because it is the only thing that passes between generations over time...”

 

With all respect to Cairns-Smith, that isn't true. The protocells will vary between individuals, because they will have different proteins within them. Some of those individuals will have proteins with higher catalytic activity than others -- including activity to make more proteins. Daughter cells will also differ, because as the cell fissions, each daughter will end up with a slightly different composition. So now we have natural selection working favoring those protocells that 1) metabolize better and 2) reproduce faster.

 

As such, all biologically living things owe a debt of gratitude to your prebioants, but however splendid they are they don't represent what happened when abiogenesis became a reality.

 

You keep repeating this, but you don't give us any data on how the protocells are not alive. Except for your strawman insistence on having directed protein synthesis. Again, several papers have shown how that can arise later.

 

Since you like to quote but not read data, here' Fox's sequence of early life:

1. Formation of amino acids from primordial precursors (water, ammonia, carbon dioxide, methane, oxygen, hydrogen, etc.) [M-U experiments and Miller and Orgel].

2. Formation of proteinoids by polymerization of sets of amino acids. [Fox and others].

3. Formation of protocells by contact of proteinoids with water [Fox and others]. (this is abiogenesis)

4. Synthesis of RNA within the microspheres [Fox]

5. Replication of RNA. [Orgel]

6. Development of the genetic code.

 

Consider this paper:

1. AM Poole, DC Jeffares, D Penney, The path from the RNA world. J. Molecular Evolution 46: 1-17, 1998.

 

It describes a Darwinian step-by-step evolution from RNA molecules to directed protein synthesis. All intermediate steps are useful. Once you have protocells that are making RNA (as it has been shown protocells do), then directed protein synthesis (what you call the "genetic code") is going to follow -- as a product of evolution. Not the start of evolution, but the product of Darwinian evolution.

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Wait, isn't that cheating just a bit? We need to induce cleavage?

 

That was a quote from a 1975 biology book. It turns out that, when the protocells grow to a critical size, they divide on their own.

 

I thought you said that some of them are photosynthetic. Are all of them photosynthetic?

 

Bahn PR, Fox SW. Models for protocellular photophosphorylation. Biosystems. 1981;14(1):3-14.

Masinovsky Z, Lozovaya GI, Sivash AA, Drasner M. Porphyrin-proteinoid complexes as models of prebiotic photosensitizers. Biosystems 1989;22(4):305-10.

Masinovsky Z, Lozovaya GI, Sivash AA. Some aspects of the early evolution of photosynthesis. Adv Space Res 1992;12(4):199-205.

 

It turns out that porphyrins (and chlorophyll is a porphyrin) are also made when amino acids are dry heated. Initial studies didn't look at porphyrins. Remember, when you make protocells, you are going to make at least a million of them. Some of those will have porphyrins such that they are photosynthetic.

 

 

No, the protocol is quite simple, but as I said I don't want to make my own. I want to grow a colony of them from a sample of protocells, especially ones with interesting properties. You know, like culturing strains of bacteria?

 

Well, you are going to have to make your own. The protocol is so simple that this is what people have been doing: making up batches of protocells as needed for testing. So make up your own batch and then make strains if you wish.

 

Well yes, this is done in undergraduate level biology classes. Probably some high schools too. Eg for teaching aseptic technique, they have you inoculate a plate with distilled water. If something grows, you did it wrong (or were unlucky).

 

You need something more than distilled water. You need an energy source -- such as glucose. All the protocols I've seen use bacterial agar or sterilized salt solutions with sugar.

 

I test the students' sterile technique by changing culture medium every day for a week using a biological safety cabinet. But I am old enough to have been around in the days of dead air hoods. Those routinely had a fairly high rate of contamination and people did not keep continuous cultures for more than a few weeks. If you want to generate strains of protocells, you are going to need more than a month. Good luck.

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.

Are you referring to flavoprotenoid microspheres or about lipid protocells?

 

I'm referring to protocells made from 1) thermal polymerization of amino acids to proteins and 2) the addition of salt solution. For the umpteenth time, here are 2 websites for you to start on. Just read them.

http://www.theharbinger.org/articles/rel_sci/fox.html

http://www.siu.edu/~protocell/

 

We can go into more detailed papers after you read the websites.

 

In flavoprotenoid microsphores ATP generation was found but essentially it was due to irradiation of ADP in presence of Pi (which is quite intersting by itself, though), but I have not yet heard about real photosynthesis.

Could you provide a source for that ?

 

See the 3 papers I quoted earlier in this combined post.

 

And why precisely would one need a culture medium for them? I may be missing something but they do not have metabolism and hence should be pretty stable in a defined buffer. Am I missing something here?

 

The protocells I'm talking about do have metabolism, so you need a source of sugars, amino acids, and nucleotides. IOW, what you would find in the pre-biotic environment.

[CharonY]

Lucaspa, I skimmed the websites, though I did not follow every (dead) link. My question was precisely directed where DNA or RNA synthesis has been described (as I only found a somewhat newer article with lipid-protocells). I only found the table in the articles which was rather devoid of detail. But never mind that. I tracked down the references and am waiting that the librarian sends copies to me (problem with old papers). I am gonna read them in time and maybe get back for more questions (if time allows).

 

The three references you have given above are basically what I found too. Which means that a) you had to include protoporphyrins, (and by extension, as imple AA mix won't get you that) and b that is not proper photosynthesis (though a model for early photochemical reactions).

IMO it is a bit of a far shot to argue that there are photosynthetic protocells based on these claims.

Edited April 20, 2009 by CharonY

[lucaspa]

My question was precisely directed where DNA or RNA synthesis has been described

 

JR Jungck and SW Fox, Synthesis of oligonucleotides by proteinoid microspheres acting on ATP. Naturwissenschaften, 60: 425-427, 1973.

Fox, SW, Jungck, JR, Nakashima, T. From proteinoid microsphere to contemporary cell: formation of internucleotide and peptide bonds by proteinoid particles. Origins of Life 5: 227-237, 1974.

 

You might also want to read this lengthy post based on Dose and Fox's book:

http://www.asa3.org/archive/asa/199905/0230.html

 

Which means that a) you had to include protoporphyrins, (and by extension, as imple AA mix won't get you that) and b that is not proper photosynthesis (though a model for early photochemical reactions).

 

My recollection is that pigments -- flavines and pteridines --- are synthesized from the amino acids during the heating and can be detected in low quantities using mass spectrometry. Ah yes, here is part of it:

http://www.springerlink.com/content/r673818865317433/ It is these flavines and pteridines that can also act in electron transport under the stimulation of light for a primitive form of photosynthesis.

 

So we are not talking about porphyrins made by heating amino acids, but flavines and pteridines. This is why preparations of protocells are often pigmented.

 

Porphyrins are made in the same chemical reactions that produce amino acids from methane and ammonia: http://books.google.com/books?id=LKy0weDEFp8C&pg=PA8&lpg=PA8&dq=porphyrins+synthesized+heating+amino+acids+proteinoids&source=bl&ots=4Ys8Ay8J7R&sig=X9JNzwx_71S4cIpe2uwhnFSreqk&hl=en&ei=LgLtSYryBduLtgfz4aTNDw&sa=X&oi=book_result&ct=result&resnum=3

 

 

 

The protoporphyrins can be incorporated into protocells when they are made. Protocells can form when there is a complex mixture of amino acids, sugars, nucleotide, fatty acids, etc.

 

During the experiments, in order to get a level of activity that can be detected by the assays used, exogenous protoporphyrins were added.

 

IMO it is a bit of a far shot to argue that there are photosynthetic protocells based on these claims.

 

It's not photosynthesis the way modern cells do it, but it is conversion of sunlight, water, and carbon dioxide to storage molecules.

 

"The early evolution of a photocatalytic system of the porphyrin type, able to efficiently collect and utilize solar energy for primary electron transfer is discussed. Experimental results concerning some spectral and photochemical properties of the porphyrins, biosynthetic precursors of chlorophyll and their complexes with polymeric templates are reviewed. Protoporphyrin IX associated with pigmented proteinoid is demonstrated to be a favourable candidate for a role of a photosensitizer of the first photosynthetic reaction centers. The origin and early evolution of the photosynthetic electron transfer chain and of the phosphorylating mechanism are discussed with emphasis on the energetic mechanisms of archaebacteria."

Edited April 20, 2009 by lucaspa

[scrappy]

...(did you read the websites?)...

lucaspa, I’ve read your recommended articles about protocells and pigmented proteinoids. Yes, they do speak to certain possible aspects of the “hypothetical participation of proteinoid melanoidin pigments in prebiotic evolution.” I have no quibble with this line of research. It seems important enough to me. But I struggle to understand why only chemical analogues are important to “prebiotic evolution.” Life—biological life, anyway—is more than just little cells full of vigorous chemicals…much more!

 

But then I’m of a “Genetic First/RNA World” persuasion. I can’t so lightly pass over the obvious requirement of genes to make living things biologically alive. Still, I’ll respect your POV, made all the more credible by a recent article coauthored by Harold Morowitz.

 

If you haven’t already read the article “The Origin of Life” in the May-June 2009 issue of American Scientist, written by James Trefil, Harold J. Morowitz and Eric Smith (not yet available on the Internet), you may want to, because it largely supports your POV. Whenever I see Harold Morowitz attach his name to something I pay attention; he of course is a major player in p-chem and biochem. I used his 1968 texbook “Energy Flow in Biology” in grad courses I took in the early ‘70s. It’s still on my bookshelf and I still use fairly often.

 

The main point of Trefil et al.’s 2009 article is to add theoretical support to Albert Szent-Gyorgi’s claim: “Life is nothing but an electron looking for a place to rest.” And I find this article to be compelling…up to a point.

 

Here are a few of my observations of this article:

 

1. The formation of protocells in the early stages of abiogenesis may not have been necessary, because the pore spaces in rocks could have provided the needed enclosure to facilitate certain aspects of prebiotic chemistry.

 

2. Morowitz and his crew prefer the “Metabolism First” hypothesis to the “Genetic First/RNA World” hypothesis, mainly because they see life as system of chemical analogues, with its perfunctory genetics coming along naturally and as needed in the course of abiogenesis (but just how that happened, they do not elaborate).

 

3. The authors see the citric acid cycle—the heart of all metabolic pathways—as a strong indicator of early metabolism (almost like a chemical “fossil”).

 

4. The authors are working in the area of nonequilibrium statistical mechanics (akin to Ilya Prigogine’s far-from-equilibrium thermodynamics, I presume), looking for nonenzymatic chemical reactions that led to modern life.

 

5. The authors are predisposed to see abiogenesis as a chemical necessity rather than a matter of pure chance.

 

Now, here’s my main objection to this hypothesis: Life, to me, is more than a system of chemical analogues. At some critical point in the process of abiogenesis—the point where biological life qualified as being truly alive—there had to be “invented” a genetic language capable of recording a cell’s building instructions in digital code. And not only that, but also a system had to be “invented” for transcribing and translating that digital code into a cell’s infrastructure.

 

Do you know of any principle of nature—the kind of principle that scientists should be looking for—that accounts for the reduction of chemical analogues into a digital code? Not even Morowitz can persuade me to accept that such an incredible feat should be regarded as perfunctory in the process of abiogenesis.

[cameron marical]

Life—biological life, anyway—is more than just little cells full of vigorous chemicals…much more!

 

doesnt the cell theory state that one of the requisits for life is at least one cell? one prokaryotic organism is alive according to the cell theory, and it isnt much more the cells and vigourus chemicals. if anything, its less, becuase its only one cell.{please correct me if im wrong}

 

Now, here’s my main objection to this hypothesis: Life, to me, is more than a system of chemical analogues. At some critical point in the process of abiogenesis—the point where biological life qualified as being truly alive—there had to be “invented” a genetic language capable of recording a cell’s building instructions in digital code. And not only that, but also a system had to be “invented” for transcribing and translating that digital code into a cell’s infrastructure.

 

im not quite understanding what your saying, are you suggesting an intelligent designer is needed for protocells and cell formation? why do protocells need a digital code to exist?

 

i think that abiogenesis can explain how life can form quite well. but i may be wrong.

 

btw:this thread is a library of info. ive learned quite a bit from the people participating in this. thanks.

[scrappy]

im not quite understanding what your saying, are you suggesting an intelligent designer is needed for protocells and cell formation? why do protocells need a digital code to exist?

No, I’m not saying an intelligent designer is needed to make life. That would be just another unexplained black box in the abiogenesis hypothesis. What I am saying is that scientists know of no principle that allows for the reduction of a chemical processes to any kind of digital code in any system. (When I say “digital” I’m following Dawkins’ assertion that genes are “pure information,” and that they are assembled out of just four kinds of information bits—nucleotides, i.e. digits). There is no doubt that digitally genetic information emerged at least once, somewhere somehow, but we haven’t enough knowledge about it to understand how it happened during abiogenesis, here on Earth or elsewhere.

 

I also take the position that there is only one kind of biological life—digitally genetic life—and that, in itself, may tell us that abiogenesis was a one-time phenomenon. Others will tell you that as soon as the first life form emerged it eat up all of its competitors, leaving not a trace of them. I also think this is a risky assumption.

 

btw:this thread is a library of info. ive learned quite a bit from the people participating in this. thanks.

At least you're getting two POVs: genes first v. metabolism first. It will take a lot more knowledge to see who's right.

[GDG]

what do cells live off of exactly?

 

i know this is a little of topic, but this q has been bugging me for a while.

 

also, is there anything other than cells that viruses and reproduce and feed off of?\

 

thank you.

 

Oxygen, water, glucose, amino acids, lipids, minerals, vitamins. All of this is carried in your blood (O2 by your red blood cells; everything else pretty much in the plasma or stuck to other plasma proteins). This is why all your cells are within a few cell diameters from the nearest capillary.

 

Viruses, by definition, cannot replicate without using some of the molecular machinery of a host cell. The virus's proteins subvert the host cell's protein synthesis apparatus to churn out more viral proteins (and copies of the viral genome). Viruses don't really metabolize at all, and rely on whatever the host organism provides.

[cameron marical]

how are viruses replicated in the lab?

 

do they put cells in a petry dish and let the viruses copy themselves through them?

 

if so, what cells are ideal?

 

thanks.

[scrappy]

how are viruses replicated in the lab?

 

do they put cells in a petry dish and let the viruses copy themselves through them?

Would you believe mail-order genetic kits?

 

Quoted from the article: "A small group of US researchers reported on Thursday they had built an infectious poliovirus from scratch, using only a genetic blueprint from the Internet as a guide and mail-order, and tailor-made sequences from a laboratory supply service to assemble the deadly virus. The man-made virus led to paralysis or death in mice engineered to carry the human receptor for poliovirus…It is the closest anyone has yet come to creating life in a test tube — although the scientists deny a virus, which is not a living cell but which can replicate itself, is alive in the same sense as a bacterium, plant, or a human being."

 

Also worth noting here is the assertion that a virus is not a living cell. There are many good scientists who would disagree with that assertion. Nevertheless, in a very specific way not unlike computer viruses, they are digital parasites.

[cameron marical]

as strange and actually kind of scary as that is, that doesnt really answer my question if how viruses are replicated in the lab. thanks for the info though.

 

also, i dont beleive that viruses are alive. they replicate, thats all. copy machines replicate stuff, are they alive?

[scrappy]

as strange and actually kind of scary as that is, that doesnt really answer my question if how viruses are replicated in the lab. thanks for the info though.

 

also, i dont beleive that viruses are alive. they replicate, thats all. copy machines replicate stuff, are they alive?

cameron: The “how?” question you are asking is merely a lab-tech question. Here is how scientists replicate hepatitis C virus in laboratory. From the article:

 

“The NIDDK group used a strain of HCV that would have applications to the greatest number of people - genotype 1, the major type of HCV of human infections worldwide and the type most resistant to current therapies. They constructed an HCV replica using a DNA copy of the original HCV single-strand RNA genome. They placed the DNA copy between two ribozymes, RNA molecules that have enzymatic function and can cleave RNA sequence at specific locations. These two ribozymes were designed to generate the correct ends of the HCV genome and to act as start and stop buttons to gene activity. The construct was "naked," meaning that it contained only nucleic acids, the genetic material of the virus, and did not have the HCV viral envelope, a protective shell of lipids and proteins that surrounds the viral RNA in fully-formed HCV. The naked HCV construct was then placed into human liver cells in a cell culture medium.”

 

The short answer then is that they used live human liver cells to culture their virus (“in vitro”).

 

Whether or not viruses are alive is a great question. Clearly, they are not living organisms (they cannot reproduce autonomously). But virologists and microbiologists usually differentiate live viral cultures from a dead ones, making the issue confusing. You may recall the big flap in the 1950s over Salk’s polio vaccine verses that of Sabin. Salk vaccinated with live viruses while Sabin used dead ones.

[GDG]

as strange and actually kind of scary as that is, that doesnt really answer my question if how viruses are replicated in the lab. thanks for the info though.

 

also, i dont beleive that viruses are alive. they replicate, thats all. copy machines replicate stuff, are they alive?

 

Yes, to replicate viruses in the lab, you would use a dish (or tank, or reactor) full of host cells. For example, to produce bacteriophage, you start with a lawn of bacteria and innoculate it with your phage.

[MustKnow]

as strange and actually kind of scary as that is, that doesnt really answer my question if how viruses are replicated in the lab. thanks for the info though.

 

also, i dont beleive that viruses are alive. they replicate, thats all. copy machines replicate stuff, are they alive?

 

lol. Makes you wonder what is alive then. For instances if you find a microbe on another planet they say there is life, but a microbe isnt really alive is it? A microbe seems more like a machine or a computer program too me, that uses the laws of physics and chemistry as its software, which i find fascinating.

[GDG]

lol. Makes you wonder what is alive then. For instances if you find a microbe on another planet they say there is life, but a microbe isnt really alive is it? A microbe seems more like a machine or a computer program too me, that uses the laws of physics and chemistry as its software, which i find fascinating.

 

A "microbe" is just a microorganism, which includes bacteria and microscopic (e.g., unicellular) fungi. Most microbes are definitely alive (except for the dead ones ). Although us multicellular organisms are more complicated (most of us, anyway...), we all follow the laws of physics and chemistry

[MustKnow]

A "microbe" is just a microorganism, which includes bacteria and microscopic (e.g., unicellular) fungi. Most microbes are definitely alive (except for the dead ones ). Although us multicellular organisms are more complicated (most of us, anyway...), we all follow the laws of physics and chemistry

 

I dont see how you could say they are alive, they are machines they follow a set of rules and preform the tasks within their dna, it seems more like their DNA acts as their brain.

[Sisyphus]

I dont see how you could say they are alive, they are machines they follow a set of rules and preform the tasks within their dna, it seems more like their DNA acts as their brain.

 

We, too, are "machines" that follow the laws of physics and chemistry. We're just a lot more complicated.

[Mr Skeptic]

We, too, are "machines" that follow the laws of physics and chemistry. We're just a lot more complicated.

 

We're not really all that complicated compared to other living things. We're smarter though.

[MustKnow]

We, too, are "machines" that follow the laws of physics and chemistry. We're just a lot more complicated.

 

not entirly machines. I can decide to destory myself, or where i want to go or eat. A microbe machine works strictly on chemistry. A microbe seems to me that it works much more like a computer program and if statements. Using magnetic pulls and chemistry to cause its actions to take place. Its hard to explain. The best way i can explain what i am seeing to another person is by using computer programs as examples.

[Mokele]

But your decisions are strictly chemistry too. Imaging studies of the brain have shown that most of our "decisions" are instinctive or conditioned reactions, and our 'reasons' are usually post-hoc rationalizations, at most.