FUNDAMENTALS OF BIOCHEMISTRY. READER - G. A. Sevryukova - 2018

CHAPTER 1. FROM THE HISTORY OF BIOCHEMISTRY AS A SCIENCE. THEORIES OF THE ORIGIN OF LIFE

Class="right">A professional differs from an amateur in knowing their predecessors.

1.1. Biochemistry: The Science of the Molecular Foundations of "Living Systems"

Biochemistry is the fundamental science of the chemical COMPOSITION AND PROPERTIES of "living systems," as well as the metabolic and exchange processes within them that sustain life.

One of the scientific figures who significantly influenced the formation and development of biological chemistry was Nikolai Ivanovich Vavilov (Fig. 1). A Soviet biologist, geneticist, and geographer, one of the pioneering organizers and leaders of biological science in the Soviet Union, and an academician of the USSR Academy of Sciences, he openly opposed Academician Trofim Denisovich Lysenko in the early 20th century because he rejected his ignorant Conclusions.

Fig. 1. Nikolai Ivanovich Vavilov (1887-1943)

Trofim Denisovich Lysenko ("Lysenkoism") believed that absolutely any plant could be bred artificially, including through environmental influence. He denied the universally accepted theory of chromosomal inheritance.

"Lysenkoism" was a campaign of persecuting geneticists, denying genetics, and banning genetic research in the USSR, lasting approximately from the mid-1930s to the first half of the 1960s. In a broader sense, it refers to any administrative persecution of scientists for their "politically incorrect" scientific views.

Beginning in 1939, with the tacit support of the country's top leadership, T. D. Lysenko and his supporters orchestrated a devastating blow to genetic science in the USSR. In 1940, N. I. Vavilov was arrested while on a scientific expedition. He was stripped of all his positions and exiled to labor camps in Kolyma. The investigation against him dragged on for a long time, yet even in confinement, Nikolai Ivanovich Vavilov did not cease his scientific work. He died in prison on January 26, 1943. He was posthumously rehabilitated, the institute he once led was named after him, and a gold medal bearing his name was established for outstanding achievements in agriculture.

Another founding figure of Russian experimental biology is Nikolai Konstantinovich Koltsov (Fig. 2). A biologist, corresponding member of the St. Petersburg Academy of Sciences (1916), academician of the V. I. Lenin All-Union Academy of Agricultural Sciences (1935), and the organizer and first director (1917-1939) of the Institute of Experimental Biology, N. K. Koltsov was the first, in 1928, to formulate the hypothesis of the Molecular Structure and template reproduction of Chromosomes ("hereditary molecules"), anticipating the fundamental principles of modern molecular biology and genetics.

Fig. 2. Nikolai Konstantinovich Koltsov (1872-1940)

In December 1936, a special session of VASKhNIL was convened to combat "bourgeois genetics." N. I. Vavilov, N. K. Koltsov, and other prominent scientists spoke out in defense of genetics.

N. K. Koltsov addressed a letter to the president of VASKhNIL emphasizing the responsibility of all scientists for the state of science in the country. In response, at a general meeting of the VASKhNIL active on March 26, 1937, N. K. Koltsov faced a wave of fury for his "politically harmful" theories regarding genetics and eugenics.

Genetics is the science of heredity and variation in organisms.

Eugenics is The Theory of human hereditary health and Ways to improve it. It is divided into positive and negative eugenics.

Works criticizing "Lysenkoism" served as the primary pretext for the persecution of N. K. Koltsov. He was dismissed from his position as director of the Institute of Experimental Biology, though he was allowed to keep his laboratory. Koltsov died of a Heart attack in Leningrad.

During this period of dramatic events for biology—when scientists faced immense pressure and proponents of modern biological knowledge were expelled from biology departments—certain scholars, including I. G. Petrovsky, the rector of Moscow State University, and S. P. Kapitza, made concerted efforts to save biology as a science.

During this turbulent era of confrontation within biological science, theories concerning the Physical Foundations of living matter were extremely popular. Research aimed at uncovering physical or chemical phenomena in living organisms became the starting point for new branches of biological science (physics and chemistry as sciences of nature; biophysics and biochemistry as sciences of living nature).

The Subject Matter of the course "Fundamentals of Biochemistry" is the Molecular Basis of life processes.

The main objective of the course "Fundamentals of Biochemistry" is to uncover the molecular foundations of life, provide insight into the concrete ways living nature resolves various practical challenges, and help students—future highly qualified specialists—fully appreciate the paramount issue facing humanity: the preservation of living nature and human health.

All "living systems" are fundamentally based on metabolic and energy-exchange processes. These processes consist of a combination of chemical and physical alterations, involving transformations of matter and energy that constantly and continuously occur within a living Organism and all its structures.

METABOLISM is an essential prerequisite for life. It distinguishes living matter from inanimate nature, and the world of living organisms from the inorganic realm. "...Metabolism can also occur in inorganic bodies because Chemical Reactions constantly take place everywhere, even if very slowly. However, the difference lies in the fact that in inorganic bodies, metabolism destroys them, whereas in organic bodies, it is a necessary condition for their existence." Life is possible only as long as metabolism continues, maintaining the existence of living protoplasm and driving its self-renewal. The cessation of metabolic processes results in death, the destruction of protoplasm, and the irreversible breakdown of its characteristic chemical compounds, primarily Proteins.

All physiological Functions—such as growth, development, reproduction, Nutrition and Digestion, Respiration and excretion, movement, and responses to environmental changes—are closely linked to Metabolism and Energy Exchange. The foundation of any physiological function lies in a specific set of matter and energy transformations. This applies equally to the functions of an individual Cell, tissue, organ, or the organism as a whole.

1.2. Theories of the Origin of Life

The question of how life originated on Earth remains highly relevant today. Several theories regarding THE ORIGIN OF life have been proposed.

The Adsorption Theory. The idea that life originated on abiogenic crystal templates was put forward by the renowned philosopher and crystallographer J. D. Bernal. The inception of life, or The Emergence of primitive primary organisms, is associated with the adsorption of chemically active substances onto microscopic clay particles formed from ancient rocks and deposited in river mouths washed by sea tides. In 1933, it was suggested that a living cell is, in essence, a liquid crystal.

William Martin of Heinrich Heine University Düsseldorf (Germany) and Michael Russell from the Scottish Environmental Research Centre at the University of Glasgow (UK) argue that the first living organisms on Earth may have emerged inside rocks lining the ocean floor. Their hypothesis is unique compared to other theories on the origin of life because it proposes that The formation of proteins and self-replicating molecules preceded the Formation of the cell itself.

Carried by thermal Water currents, ammonium ions (NH₄⁺) and carbon monoxide (CO) enter these micro-compartments, where iron sulfide acts as one of the catalysts for the synthesis of Organic compounds from inorganic precursors. These simple compounds became concentrated within iron sulfide "chambers," which could have driven the formation of complex molecules such as proteins and Nucleic Acids.

The Low-Temperature or Cooling Theory. The work of prominent Romanian scientists C. Simionescu and F. Deneş focuses on the Chemical aspects of the origin of life. According to their model, the primary energy source that initiated the initial chemical processes was cold plasma, which induced the formation of active particles (radicals) in a gaseous medium under low atmospheric pressure. The recombination of these active particles on crystal templates led to the emergence of macromolecular compounds and, subsequently, protobiopolymers.

L. Mukhin’s Volcanic Model of Prebiotic Synthesis. Taking a critical view of The Role of UV radiation in forming monomer precursors for complex organic molecules, Mukhin favored volcanic processes on the primitive Earth. He viewed volcanoes not only as a source of energy but also as suppliers of the components necessary for organic synthesis (methane, ammonia, hydrogen). In zones of submarine volcanism and hydrothermal vents, significant temperature and pressure gradients create conditions favorable for the preservation of synthesized organic molecules. Numerous natural catalysts and sorbents may have further facilitated the accumulation and subsequent evolution of organic compounds.

However, this model, like all preceding ones, fails to explain how life, The Genetic Code, and the reproduction mechanisms of living systems came to be. This gap led F. Crick and L. Orgel to propose the directed panspermia model, which attributes the origin of life on Earth to the deliberate seeding by extraterrestrial civilizations older than the Sun. Meanwhile, J. Berger suggested that the genetic code is a relic inherited from living systems of a previous cycle of the Universe.

Given the accumulated knowledge of Cell Structure and reproduction mechanisms, many researchers studying the origin of life believe that the emergence of "living matter" must be approached through the genesis of The Cell as a whole, rather than its isolated components. A cell is a "millionfold community" of molecules forming a unified liquid-crystalline complex. Isolated fragments of this complex, including Viruses and Phages, are not viable. Therefore, once we understand how and why a cell operates as an aperiodic, homeostatic, self-reproducing liquid crystal, we will be able to understand how life began. To this day, these questions remain unanswered.