continue with the trial last week on the origin of life.
For 30 years the existence of DNA and protein was more than supported, as well as its importance for the functioning of life. However, ribonucleic acid (RNA) were still somewhat excluded from the molecular theory of life. In 1939, Torbjörn Caspersson, the same guy who in 1936 had discovered that the DNA should be a polymer, together with collaborators, showed that the RNA content of cells is greater than that of DNA and therefore suggests an implication in protein synthesis. His hypothesis is the true precursor of dogma (I prefer to call it theory) of molecular biology as we know it today.
Nobody gives a lot of ball to Caspersson until Severo Ochoa discovers the main role of RNA in the early 50 (which makes him win the Nobel Prize some years later.) I was finally clear that the DNA served as template for the synthesis of a copy of RNA, which would be the guide for the synthesis of proteins within cellular particles called ribosomes (as protein and ribonucleic acids were inside). Finally, early 60's you will discover the different types of RNA, messenger RNA, the RNA transferring and ribosomal RNA (an RNA that was in the mature ribosomes, constitutively, helping in the process of protein synthesis).
However ... As we said in the previous episode, the RNA was fragile and unstable. No one thought of him rather than as a transmitter of information. The DNA library was like hardcover books and RNA, only the crappy photocopy on recycled paper. No matter were discovered viral genomes RNA composed entirely (as in the first virus discovered, the Snuff Mosaic for example). No matter ... Overall, viruses were not bodies, right?
But finally in 1965 ... an interesting article had appeared in a consolidated and "journal" Nature Englishman. They said they had discovered the process of reverse transcription. An RNA molecule was able to copy to give DNA. In 1970, Baltimore finally isolated the enzyme responsible called reverse transcriptase inhibitors (although the name is populizaría then as reverse transcriptase, structure in the image). The process ultimately define a complete family of viruses that used this strategy in its cycle of reproduction (the Retroviridae). He had confirmed another hypothesis of Crick ... RNA into DNA could retrocopiarse.
Finally, in 1967, Crick (along with some other partners), after analyzing the proposed three-dimensional structure of RNAs (a structure sequence dependent variable, such as proteins) considered the possibility that RNA could, like protein polypeptides, catalyze reactions as an enzyme. Like almost everything in his legendary proposed sketch of the Central Dogma of Biology Molecular
to 1958, it was also demonstrated. However, they had to wait until 1981 and 1985, when be discovered the first catalytic activities of the ribonucleic acids (vital participation in protein synthesis in the ribosome and self-hydrolysis, respectively), the Nobel finally went to Cech and Altman. These enzymes would ribonucleic acid and finally called ribozymes (using the same root as enzymes). The picture shows the ribozyme "hammerhead", the smallest of all. Catalyzes autohidrolítica activity in which provided that the hydroxyl group, OH, (in red) attack phosphate, PO 4 (orange-pink).
It was not even a year until finally in 1986 the hypothesis of the primitive world of RNA curd full hand of Walter Gilbert. The hypothesis was simple and in fact had been stated previously by Woese in 1968 (Crick's collaborator in his study of three-dimensional structure of RNA) and Rich (even 5 years before Woese). It was all quite intuitive ... If the RNA could retrotranscribirse to give rise to DNA and could also lead to protein ... and was also able to function as a catalyst .... and also synthesis machinery itself proteins in modern cells, the ribosome, RNA catalysis used to make proteins .... ie if, in short, the RNA could have all the functions of the macromolecules of living organisms had to be the ancestor!
RNA and DNA had dethroned the precursor molecule of life. In the primitive world of RNA Gilbert, the first living molecules would be small RNA, interacting with each other, catalyze reactions that would facilitate their ability to replicate.
(I make an aside here to know many people who may need it. The catalytic ability of RNA was key since the catalytic theory of life was practically established in the thermodynamic study of life, part of enzymology. The idea is that the reactions are highly ordered life, going against the trend chaotic nature. That is why there must be catalytic systems to provide energy inputs needed to achieve reactions that generate order in certain cell sites. The reactions that are almost impossible outside of a living environment coupled reactions proved to be a second reaction, called secondary or coupled, which provide energy and chemical-mechanical electro-conformational-etc. to alleviate very negative effect on the primary reaction. The "cost of ATP is the most common of these, but neither of the only hint. The ability of RNA to catalyze reactions was thus a key step in demonstrating the ability of this molecule as a precursor to all the others.)
course we can go much further back than the RNA and ask things like what RNA where did it start? Was there a prior molecule also alive? Is the precursor a precursor? "The RNA is the first? And how organic molecules arose then?
All these questions are equally or more important than the first. And the funny thing is that were made long before of knowing that even the structure of DNA. I am speaking of Miller and Urey experiment. Yes .. and I left the so-called "classic experiment on the origin of life" to the end ... Especially because I think the ugliest and least credible of all the rest (which incidentally are still only hypotheses and theories) ... In 1953 these two individuals conducted an experiment that could be summarized as follows:
RECIPE FOR LIFE
1) Add to a closed glass tubes and flasks the following components:
- Methane gas
-
Water - Hydrogen gas
- Ammonia
2) Close the valve
3) Heat the flask where it places
water 4) Issue a frequent and random electrical spark in one of the areas through which pass the gas and 4000 million years expect
5) Collect the living liquid inside the flask.
Although it may seem ironic is basically what these guys did. Clearly assumed that there were far fewer items on the Early Earth than they actually are living beings. Also, do not wait so long either (and clearly not met a baby lizard in the flask liquid). However, after a few days gave a very interesting series of compounds within the "primordial soup" del matraz acuoso (sí, la frase "caldo primigenio" proviene de su propio artículo, en el que proponen que la Tierra en el momento del Origen de la vida era como un "caldo" donde abundaban las moléculas orgánicas más básicas). Es más, el 10-15% del carbono se había asimilado en forma orgánica. Aparecían cosas como la Urea y Aminoácidos (y algunos precursores de nucleótidos). De hecho fue este experimento (y luego muchos otros que le siguieron, inspirándose en él) el que centró la teoría de la evolución durante muchos años sobre las proteínas como molécula primigenia. Crick fue el primero que se levantó
contra la hipótesis de las protein as the source with Central Dogma, shown at successive times. His idea was quite interesting. As there was loss of information in the passage of nucleic acids to proteins (as the genetic code was degenerate), the protein sequence could not refer to precise sequences of nucleic acids, but many possible sequences. The protein combining a few kiloDalton was so infinite that no protein could not even give 2 molecules of DNA or RNA identical even if they tried all the time in the history of planet Earth. It is now clear that at least nucleic acids (or something very like them) should have been the former.
The next time we discuss a little about the possible origin of the cell, ending with the criticisms made by the Systems Biology to all this we have talked. With a little luck it will start to say something about how molecular biology was transformed from Dogma to be disciplined, ... Technology finally ...
For 30 years the existence of DNA and protein was more than supported, as well as its importance for the functioning of life. However, ribonucleic acid (RNA) were still somewhat excluded from the molecular theory of life. In 1939, Torbjörn Caspersson, the same guy who in 1936 had discovered that the DNA should be a polymer, together with collaborators, showed that the RNA content of cells is greater than that of DNA and therefore suggests an implication in protein synthesis. His hypothesis is the true precursor of dogma (I prefer to call it theory) of molecular biology as we know it today.
Nobody gives a lot of ball to Caspersson until Severo Ochoa discovers the main role of RNA in the early 50 (which makes him win the Nobel Prize some years later.) I was finally clear that the DNA served as template for the synthesis of a copy of RNA, which would be the guide for the synthesis of proteins within cellular particles called ribosomes (as protein and ribonucleic acids were inside). Finally, early 60's you will discover the different types of RNA, messenger RNA, the RNA transferring and ribosomal RNA (an RNA that was in the mature ribosomes, constitutively, helping in the process of protein synthesis). With all this, the proposals to Francis Crick (yes, the Watson-Crick) held between 56 and 58, were consolidated on a strong theory that was quickly becoming as dogma the fact that checking the width and length of the tree of life (the hypotheses are summarized in the following image).
However ... As we said in the previous episode, the RNA was fragile and unstable. No one thought of him rather than as a transmitter of information. The DNA library was like hardcover books and RNA, only the crappy photocopy on recycled paper. No matter were discovered viral genomes RNA composed entirely (as in the first virus discovered, the Snuff Mosaic for example). No matter ... Overall, viruses were not bodies, right?
But finally in 1965 ... an interesting article had appeared in a consolidated and "journal" Nature Englishman. They said they had discovered the process of reverse transcription. An RNA molecule was able to copy to give DNA. In 1970, Baltimore finally isolated the enzyme responsible called reverse transcriptase inhibitors (although the name is populizaría then as reverse transcriptase, structure in the image). The process ultimately define a complete family of viruses that used this strategy in its cycle of reproduction (the Retroviridae). He had confirmed another hypothesis of Crick ... RNA into DNA could retrocopiarse.
Finally, in 1967, Crick (along with some other partners), after analyzing the proposed three-dimensional structure of RNAs (a structure sequence dependent variable, such as proteins) considered the possibility that RNA could, like protein polypeptides, catalyze reactions as an enzyme. Like almost everything in his legendary proposed sketch of the Central Dogma of Biology Molecular
to 1958, it was also demonstrated. However, they had to wait until 1981 and 1985, when be discovered the first catalytic activities of the ribonucleic acids (vital participation in protein synthesis in the ribosome and self-hydrolysis, respectively), the Nobel finally went to Cech and Altman. These enzymes would ribonucleic acid and finally called ribozymes (using the same root as enzymes). The picture shows the ribozyme "hammerhead", the smallest of all. Catalyzes autohidrolítica activity in which provided that the hydroxyl group, OH, (in red) attack phosphate, PO 4 (orange-pink). It was not even a year until finally in 1986 the hypothesis of the primitive world of RNA curd full hand of Walter Gilbert. The hypothesis was simple and in fact had been stated previously by Woese in 1968 (Crick's collaborator in his study of three-dimensional structure of RNA) and Rich (even 5 years before Woese). It was all quite intuitive ... If the RNA could retrotranscribirse to give rise to DNA and could also lead to protein ... and was also able to function as a catalyst .... and also synthesis machinery itself proteins in modern cells, the ribosome, RNA catalysis used to make proteins .... ie if, in short, the RNA could have all the functions of the macromolecules of living organisms had to be the ancestor!
RNA and DNA had dethroned the precursor molecule of life. In the primitive world of RNA Gilbert, the first living molecules would be small RNA, interacting with each other, catalyze reactions that would facilitate their ability to replicate.
(I make an aside here to know many people who may need it. The catalytic ability of RNA was key since the catalytic theory of life was practically established in the thermodynamic study of life, part of enzymology. The idea is that the reactions are highly ordered life, going against the trend chaotic nature. That is why there must be catalytic systems to provide energy inputs needed to achieve reactions that generate order in certain cell sites. The reactions that are almost impossible outside of a living environment coupled reactions proved to be a second reaction, called secondary or coupled, which provide energy and chemical-mechanical electro-conformational-etc. to alleviate very negative effect on the primary reaction. The "cost of ATP is the most common of these, but neither of the only hint. The ability of RNA to catalyze reactions was thus a key step in demonstrating the ability of this molecule as a precursor to all the others.)
course we can go much further back than the RNA and ask things like what RNA where did it start? Was there a prior molecule also alive? Is the precursor a precursor? "The RNA is the first? And how organic molecules arose then?
All these questions are equally or more important than the first. And the funny thing is that were made long before of knowing that even the structure of DNA. I am speaking of Miller and Urey experiment. Yes .. and I left the so-called "classic experiment on the origin of life" to the end ... Especially because I think the ugliest and least credible of all the rest (which incidentally are still only hypotheses and theories) ... In 1953 these two individuals conducted an experiment that could be summarized as follows:
RECIPE FOR LIFE
1) Add to a closed glass tubes and flasks the following components:
- Methane gas
-
Water - Hydrogen gas
- Ammonia
2) Close the valve
3) Heat the flask where it places
water 4) Issue a frequent and random electrical spark in one of the areas through which pass the gas and 4000 million years expect
5) Collect the living liquid inside the flask.
Although it may seem ironic is basically what these guys did. Clearly assumed that there were far fewer items on the Early Earth than they actually are living beings. Also, do not wait so long either (and clearly not met a baby lizard in the flask liquid). However, after a few days gave a very interesting series of compounds within the "primordial soup" del matraz acuoso (sí, la frase "caldo primigenio" proviene de su propio artículo, en el que proponen que la Tierra en el momento del Origen de la vida era como un "caldo" donde abundaban las moléculas orgánicas más básicas). Es más, el 10-15% del carbono se había asimilado en forma orgánica. Aparecían cosas como la Urea y Aminoácidos (y algunos precursores de nucleótidos). De hecho fue este experimento (y luego muchos otros que le siguieron, inspirándose en él) el que centró la teoría de la evolución durante muchos años sobre las proteínas como molécula primigenia. Crick fue el primero que se levantó
contra la hipótesis de las protein as the source with Central Dogma, shown at successive times. His idea was quite interesting. As there was loss of information in the passage of nucleic acids to proteins (as the genetic code was degenerate), the protein sequence could not refer to precise sequences of nucleic acids, but many possible sequences. The protein combining a few kiloDalton was so infinite that no protein could not even give 2 molecules of DNA or RNA identical even if they tried all the time in the history of planet Earth. It is now clear that at least nucleic acids (or something very like them) should have been the former. The next time we discuss a little about the possible origin of the cell, ending with the criticisms made by the Systems Biology to all this we have talked. With a little luck it will start to say something about how molecular biology was transformed from Dogma to be disciplined, ... Technology finally ...
