Author: Yana Nencheva, Biochemist, PhD candidate in Biophysics

There are numerous hypotheses about the birth of the world and the emergence of life. There are certainly people who have their own understanding of how all this happened, but who are we to judge. Otherwise, on the most basic level, the known, most common hypotheses are subject to two groups of ideas:

Life was born when matter and intellect merged - it is about the hypothesis that the creation of life is the work of a higher mind,whether it be aliens,a particular religion or individual deities.

Intellect is a product of the development of life, and life is a product of the development of matter - here we are talking about a set of scientific hypotheses - in which everything is the result of some processes, compounds are obtained, other substances are obtained fromthem, and so the intellect was eventually born "accidentally".

These two"formulas"are of Academician A.I. Oparin [ref.1], who, inspired by Darwin's evolutionarytheory, seeks to unravel and explain theorigin of life using the laws of chemistry and physics.

The primary broth of Academicoprine

In 1924, Oparin began to impose his theory.

The Birth of the Earth

Nearly 4.6 billion years ago, a huge cloud of gas and dust (shapeless mass) swirled in the Milky Way galaxy. At the same time,theheavier elements have begun to squirm relatively closer to the Sun. , which we know, including and the Earth. Thus formed, they gradually began to pull (as far as they could) the light elements that had not yet reached the periphery of the disk and thus formed the outer layers of their emerging planets.

Or in short: The earth was born of the dust and dirt that swirled around the Sun [ref. 3].

The emergence of life in three stages

Although we are increasingly hearing about ULO (aliens and the like), most often for the moment scientists explain that for the emergence of life we need to go through three stages.

Stage one: Formation of an atmosphere of gases

Let's imagine the Earth as a ball with a hot surface (not as hot as the Sun, of course). Young volcanoes alongside lava have "spit" and water in the form of steam, steam has condensed and fallen in the form of rain. So gradually the surface got cold. On average, its temperature was about 25 C. When the rain fell on the cooler areas, shallow reservoirs beganto form. Organic molecules are compounds in the structure of which a key element is carbon.

Pay attention to the compounds in the table:

These are 7 compoundsmade up of only 4 elements:

Second stage: Synthesis of small organic molecules (monomers)

We must not forget that at this point the Earth is subjected to the aggressive ultraviolet radiation of the Sun. Electrical voltage on the Earth's surface and clouds of gas differ greatly; adding high radioactivity, active volcanoes, crashing meteorites, the situation is starting to look scary. But these were actually great prerequisites for the formation of different new molecules.

In the shallow reservoirs (or deep cloudy puddles) of the compounds we mentioned in the first stage, new small molecules (monomers) were formed:

3 more types of compounds (so far a total of 10) of the same 4 elements - H, O, C, N.

And from them then the amino acids , fattyacids, carbohydrates and nucleotides were obtained, naturally from exactly the sameelements.

Third stage: Synthesis of organic molecules of high molecular weight (polymers)

At this stage, the small compounds (monomers)we have observed so farbind to each other and form larger and longer molecules (the so-called " polymers):

  • These chains are folded (entangled) and proteins are formed. Today, chains of 60 to 1500 amino acids are known.
  • Fatty acids, whether saturated or unsaturated, today are a component of fat (something we see on the labels of any food). Fats (oil, fat, etc.) are made up of one molecule of glycerin (the main ingredient in hand creams) and the associated three fatty acid molecules.
  • Carbohydrates are known to us as sugars and we can immediately associate them with glucose and fructose. Many glucose molecules, e.g. lead to the formation ofthelulosis. Cellulose is a building block of the cell walls of plants.
  • Nucleotide, on the other hand, lies in the structure of the genetic material - RNA and DNA.

Chaotic clustering of organic molecules

Four billion years ago, we can't talk about proteins yet, We can only imagine some degree of chaotic accumulation of organic molecules in certain areas of the Earth. protobionts. Scientists naturally also have a hypothesis about exactly how protobionts originated. Disputes are mainly related to how and how many organic compounds were needed for this unit to appear, did it spontaneously happen or again gradually [ref. 4].

 

References:

  1. Alexander Oparine Wikipedia
  2. Primary broth Wikipedia
  3. Less Than Five - How was Planet Earth Formed?
  4. Digest Biology part. 1, authors Sn. Tomova, N, Valcheva and Al. Daoud

 

The author:

👩 🔬 Yana Nencheva is a molecular biologist, Master of Biochemistry and Master of Optometry, PhD candidate in Biophysics. She has been an active organizer of a number of events since 2015, including "PhD tea" and "Eye Health Seminar", which aim to promote science in the public space. She has been the manager and co-founder of the Center for Career Guidance in Natural Sciences ScienceUp since 2019.