Five molecules out of the abundance of molecules that survived the ultraviolet radiation became the nucleic acids adenine, cytosine, guanine, thymine and uracil. Adenine has an unusually variable range of ionization energies along its reaction pathway
The atmosphere at the beginning of the Earth provided only little protection against ultraviolet radiation originating in space, and thus many pre-living molecules were exposed to it, and to radiation of other wavelengths, and had difficulty surviving at all. However, some of the molecules became stable when exposed to light and became the building blocks for the formation of life.
Five molecules out of the abundance of molecules that survived the ultraviolet radiation became the nucleic acids adenine, cytosine, guanine, thymine and uracil. Now, in a recently published study, researchers from the University of Georgia and their colleagues in Germany show that one of these building blocks of DNA and RNA, adenine, has an unusually variable range of ionization energies along its reaction pathway. This means that understanding the experimental information regarding how adenine survived exposure to radiation on a virtue will be much more complex than the researchers previously thought. The findings are also of great importance for spectroscopic measurements of heterocyclic compounds, meaning those that include at least two types of elements in their ring structure.
"Protection against light is based on the conversion of potentially harmful ultraviolet radiation into heat, and must occur at extremely fast times in order to compete with other pathways leading to the discharge of the biological molecule," explains Susanne Ullrich, professor of physics in the Department of Physics and Astronomy at the University of Georgia. "Understanding the details of these routes and their timelines is a challenge and requires close cooperation between experimental and theoretical researchers." The research findings were published in the scientific journal Physical Chemistry Chemical Physics.
The quantum chemical calculations establish for the first time ever a new baseline regarding time-dependent spectroscopic methods based on photoionization and the ability to use them to study such a family of molecules.
"Light-stable organic molecules participated in the complex molecular development that ultimately led to the formation of life on Earth," the researcher notes. "In view of the importance of nucleic acids as the components of the material that encodes the genes, the field of photophysics of nucleic acids has gained extensive theoretical and experimental interest. This new research could help clarify that inconsistency that scientists encounter while studying the data of the photoionization and photoelectron spectra of adenine."
The researchers used the most advanced research methods, such as accurate and efficient lasers and spectrometers, in order to reveal the mechanisms by which adenine is able to defend itself against damage from ultraviolet radiation. Adenine is evaporated and then it is transferred to a spectrometer by a jet stream. A pulse from the device excites the sample of molecules and a detector measures the molecule at the end of the decay time of the excited electrons returning to their original place.
This measurement is based on the photoionization process in which electrons are removed from the molecule. The kinetic energy of the removed electron is measured using the spectrometer and provides the spectroscopic information required to determine the light protection mechanism of adenine. Deciphering the measurements relies closely on knowing the ionization potential (the energy required to remove an electron from its position in the molecule) along the electron decay paths.
There is an age-old difference between the theoretical results and the experimental results regarding the examination of the ionization potential of adenine and the determination of the exact path along which the adenine decays after being excited by ultraviolet radiation. Understanding this pathway in more detail will provide insights into the survival and stability of this important building block for life, in a world where millions of genetic dangers exist.
"To our surprise, we discovered that there are significant differences in the ionization energy between two separate areas of this track," explains one of the researchers. "Given the general nature of the three routes we tested, we believe that the energy potentials measured along them can be used as a general guideline that will help in the development of systems and tests for the benefit of additional experiments, not only for adenine but also for compounds similar to it."
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Hello! Does anyone have an explanation for this?
When I'm not exposed to the sun I get dizzy and every movement I make I hear painful clicks. There are also creaks in the movement of the neck. The body is frozen.
I feel weak and exhausted. And when there is sun it passes and is released and the power returns. relief..
After being exposed to the sun for about 20 minutes, my body relaxes and relaxes as if nothing happened. During the exposure, the muscles throb throughout the body, they become soft until there is relief.
Every time the contractions come back when there is no exposure and again the feeling is not good.
It is always released and strengthened by exposure to the sun and a good and positive feeling comes.
What is ?
It is not related to vitamin D because it takes many hours for the vitamin to be absorbed from the outer layers of the skin into the bloodstream. And then, another day or two pass until it turns into the vitamin's storage hormone in the liver.
Thank you.
The resistance of the genetic material adenine is very interesting not only in the context of the formation of life but also human survival in the future outside the earth and in aspects of the development of technologies to mitigate the onset of radiation on living cells.
"Because one of these building blocks of DNA and RNA, adenine, has an unusually variable range of ionization energies along its reaction pathway. This means that understanding the experimental information regarding how adenine survived exposure to radiation on a virtue will be much more complex than the researchers previously thought. The findings are also of great importance for spectroscopic measurements of heterocyclic compounds, meaning those that include at least two types of elements in their ring structure."
Nachmani, do you write the articles only for those with degrees in chemistry and physics??
Can't you write complex things simply, or is this just your way of towering over readers who don't have your degrees?
So why is the DNA still sensitive to radiation, which causes skin cancer.
Anat, on the other hand, according to many tests, it seems that the creatures that were exposed to high energy radiation, and created life, some of them found this extremist niche. And in addition molecular stability of the molecules that make up the DNA, provides reinforcement for why the existing tools (the organic molecules that make up life) in themselves have already been optimized.
It is possible in another universe, under other planetary conditions, where life will form on the basis of different molecules.
According to the accepted estimates in the world of science, life began around geothermic chimneys at the bottom of the sea and were not exposed for a billion years to ionizing radiation, therefore they did not have to survive the ultraviolet radiation
It is possible that the existing perception is incorrect, although the likelihood of this is zero, it is more likely that the researchers' estimates are wrong