How life began
Silent, comfortable and unnoticeable death awaits each of us. It is enough to relax a little, stop doing just one thing, and the comfort of the usual things will suck you into the quagmire of stupefaction, from which it will be very difficult to get out. Recently, I noted with horror that, having run into current affairs, I embarked on this disastrous path — in the past few months I have not read a single new book. The situation had to be urgently corrected, and in order to shake the stiffening brains, I turned to popular science literature, and more specifically, to the book “The Origin of Life. From Nebula to Mikhail Nikitin's Cell. It turned out that my ideas about how life began, turned out to be very outdated, the topic was very interesting, but quite serious flaws were discovered in the book. I offer you her review.
It was here on Earth that life could have originated, a picture of Zdenek Burian
My school textbook of biology, speaking about questions of the origin of life, mentioned the Oparin coacervate hypothesis and experiments with the transmission of electricity through the Miller-Urey gas mixture. But, for a minute, Oparin’s hypothesis is 1924, and Miller’s experiments are 1953. More than half a century has passed since then, biotechnologies have become much more advanced. Now laboratories are deciphering DNA and even creating organisms with artificial genes: the latest news, created yeast, in which a third of the artificial genome. Certainly, experiments on the production of organic molecules from inorganic became more difficult. In addition, questions of the origin of life are constantly under attack by various creationists who criticize old experiments, talk about the complexity of the modern cell and try in every way to prove that life could not come about without supernatural power. Therefore, the origin of life, as well as the theory of evolution, is a rather acute topic in biology.
The book begins very far away. The entire first part is devoted, suddenly, to astronomy. From the basic concepts of orbital mechanics, the author proceeds to the structure of the solar system. The story about the origin and development of the solar system is complemented by a current comparison with the detected exoplanets. In recent years, we have become accustomed to the fact that new exoplanets are constantly being found, and the Solar System is not absolutely unique. But at the same time, we do not have some types of exoplanets, like super-earths, hot Jupiter or mini-Neptunes. After a story about the entire solar system, the conversation turns to the geology, atmosphere and climate of Venus, Earth and Mars. The three earth-like planets look very different today, and it is interesting to compare them.
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It is known from biology that life has come out of the water onto land. And some time ago there were very popular versions that life appeared on the sandbanks. However, according to the latest scientific data, according to the book, the most suitable for the emergence of life were hot land sources - “mud pots”. Promising in the 1970s, "black smokers", underwater hot springs, it seems, are not suitable - the sunlight does not reach the water. And the molecules of the nitrogenous bases of our DNA and RNA have one common feature - resistance to ultraviolet, which was much greater on the young Earth due to the absence of the ozone layer. Mud pots also provided a constant temperature and porous minerals, which worked as catalysts and created small cells for life, which had not yet learned to shut off the cell wall from the environment. Nearby were drying puddles, creating the necessary concentrations of substances, the surface illuminated by the Sun, and very close to the pores protected from the destructive ultraviolet. And in unevenly heated pores and cracks, conditions were created for the concentration of the desired molecules and RNA.
In spite of the fact that it has not yet succeeded in completely recreating the process of the emergence of RNA from dead matter, it is now that work is being done that yields extremely interesting results — it was possible in various experiments to assemble short chains of RNA and to achieve copying longer ones. There are also many explanations of chiral purity (twisting in one direction) of our protein molecules - both chemical reactions and the interaction of the first RNA translate the supposedly 50/50 ratio of left and right rotation molecules into a state with almost complete predominance of one variant.
Well, then life masters the metabolism, and, familiar to us oxygen - only from a lack of resources for more simple options. Comparatively simple and short RNAs are transformed into long DNAs, life is protected from the external environment by the cell wall, masters photosynthesis, and wrap everything up ... It is curious that the book contains arguments about alternative biochemistry, that is, about life using other chemical elements. Science fiction writers, for example, loved silicon or fluorine life, but, alas, these options are extremely unlikely. At the same time, oxygen-carbon chauvinism is not completely right - theoretically life instead of water can use carbon dioxide in a liquid form, this will require only a pressure of the order of hundreds of atmospheres.
The book can highlight the main advantages and disadvantages:
Advantages:
Disadvantages:
Very high complexity - instead of a popular science book, a textbook for universities turned out. I am an IT technician, but thanks to my microbiologist, I read colorful books in my childhood and remember from there chic pictures of a ribosome moving along a DNA chain, the mechanism of enzymes and so on. And, despite this preparation, I was constantly stuck in heels, ribozymes, nucleotides and other terms. Despite a really interesting topic and a good presentation, I twice threw down reading and finished off the book with an exceptionally strong-willed effort, while squandering obscure sections. You can read a book either by constantly getting into Google and writing down terms on a separate piece of paper (I forgot what a ribozyme and hairpin is again (), or skipping complex pieces. Also, somewhere on the two hundredth page, I wondered if The first part about the solar system? It is good and interesting, but it seems to me that it would be better to describe in detail the conditions on the ancient Earth - because of the constant comparison with Mars and Venus, the focus on what conditions were on Earth, when life appeared.
Fortunately, the author is actively engaged in popularization, and lectures on the book can be found on YouTube, they are much simpler.
PS The author, it turns out, is on Geektimes, but he is modest and does not publish his lectures and other materials, if you suddenly have questions - torment HellMaus .
It was here on Earth that life could have originated, a picture of Zdenek Burian
About the importance of the topic
My school textbook of biology, speaking about questions of the origin of life, mentioned the Oparin coacervate hypothesis and experiments with the transmission of electricity through the Miller-Urey gas mixture. But, for a minute, Oparin’s hypothesis is 1924, and Miller’s experiments are 1953. More than half a century has passed since then, biotechnologies have become much more advanced. Now laboratories are deciphering DNA and even creating organisms with artificial genes: the latest news, created yeast, in which a third of the artificial genome. Certainly, experiments on the production of organic molecules from inorganic became more difficult. In addition, questions of the origin of life are constantly under attack by various creationists who criticize old experiments, talk about the complexity of the modern cell and try in every way to prove that life could not come about without supernatural power. Therefore, the origin of life, as well as the theory of evolution, is a rather acute topic in biology.
Wider Earth
The book begins very far away. The entire first part is devoted, suddenly, to astronomy. From the basic concepts of orbital mechanics, the author proceeds to the structure of the solar system. The story about the origin and development of the solar system is complemented by a current comparison with the detected exoplanets. In recent years, we have become accustomed to the fact that new exoplanets are constantly being found, and the Solar System is not absolutely unique. But at the same time, we do not have some types of exoplanets, like super-earths, hot Jupiter or mini-Neptunes. After a story about the entire solar system, the conversation turns to the geology, atmosphere and climate of Venus, Earth and Mars. The three earth-like planets look very different today, and it is interesting to compare them.
')
The first steps
It is known from biology that life has come out of the water onto land. And some time ago there were very popular versions that life appeared on the sandbanks. However, according to the latest scientific data, according to the book, the most suitable for the emergence of life were hot land sources - “mud pots”. Promising in the 1970s, "black smokers", underwater hot springs, it seems, are not suitable - the sunlight does not reach the water. And the molecules of the nitrogenous bases of our DNA and RNA have one common feature - resistance to ultraviolet, which was much greater on the young Earth due to the absence of the ozone layer. Mud pots also provided a constant temperature and porous minerals, which worked as catalysts and created small cells for life, which had not yet learned to shut off the cell wall from the environment. Nearby were drying puddles, creating the necessary concentrations of substances, the surface illuminated by the Sun, and very close to the pores protected from the destructive ultraviolet. And in unevenly heated pores and cracks, conditions were created for the concentration of the desired molecules and RNA.
In spite of the fact that it has not yet succeeded in completely recreating the process of the emergence of RNA from dead matter, it is now that work is being done that yields extremely interesting results — it was possible in various experiments to assemble short chains of RNA and to achieve copying longer ones. There are also many explanations of chiral purity (twisting in one direction) of our protein molecules - both chemical reactions and the interaction of the first RNA translate the supposedly 50/50 ratio of left and right rotation molecules into a state with almost complete predominance of one variant.
Well, then life masters the metabolism, and, familiar to us oxygen - only from a lack of resources for more simple options. Comparatively simple and short RNAs are transformed into long DNAs, life is protected from the external environment by the cell wall, masters photosynthesis, and wrap everything up ... It is curious that the book contains arguments about alternative biochemistry, that is, about life using other chemical elements. Science fiction writers, for example, loved silicon or fluorine life, but, alas, these options are extremely unlikely. At the same time, oxygen-carbon chauvinism is not completely right - theoretically life instead of water can use carbon dioxide in a liquid form, this will require only a pressure of the order of hundreds of atmospheres.
Impression
The book can highlight the main advantages and disadvantages:
Advantages:
- Actual topic.
- Modern sources.
- An interesting presentation.
Disadvantages:
Very high complexity - instead of a popular science book, a textbook for universities turned out. I am an IT technician, but thanks to my microbiologist, I read colorful books in my childhood and remember from there chic pictures of a ribosome moving along a DNA chain, the mechanism of enzymes and so on. And, despite this preparation, I was constantly stuck in heels, ribozymes, nucleotides and other terms. Despite a really interesting topic and a good presentation, I twice threw down reading and finished off the book with an exceptionally strong-willed effort, while squandering obscure sections. You can read a book either by constantly getting into Google and writing down terms on a separate piece of paper (I forgot what a ribozyme and hairpin is again (), or skipping complex pieces. Also, somewhere on the two hundredth page, I wondered if The first part about the solar system? It is good and interesting, but it seems to me that it would be better to describe in detail the conditions on the ancient Earth - because of the constant comparison with Mars and Venus, the focus on what conditions were on Earth, when life appeared.
Fortunately, the author is actively engaged in popularization, and lectures on the book can be found on YouTube, they are much simpler.
PS The author, it turns out, is on Geektimes, but he is modest and does not publish his lectures and other materials, if you suddenly have questions - torment HellMaus .
Source: https://habr.com/ru/post/402511/
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