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اكاديمية دايموند

اكاديمية دايموند

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Biochemistry

Definition
A branch of chemistry. It is to study the chemical composition of living matter, Structure and basic life science of various chemical changes in the process of life activities.
The term Biochemistry appeared around the end of the 19th century and the beginning of the 20th century, but its origin can be traced farther back. Its early history is part of the early history of physiology and chemistry. For example, in the 1980s, A.L. Lavoisier proved that respiration and oxidation are the same as combustion. At the same time, scientists also found that photosynthesis is essentially a reverse process of plant respiration. Another example is that in 1828, F. Waller synthesized an organic substance ─ urea in the laboratory for the first time, breaking the view that organic substances can only be produced by organisms, and hitting the “vitality theory” a major blow. In 1860, L. Pasteur proved that fermentation was caused by microorganisms, but he believed that live yeast was necessary to cause fermentation. In 1897, the Bichner brothers discovered that the cell-free extract of yeast can be fermented, proving that such a complex life activity can be carried out without living cells, and finally overturned the "vitality theory".

History
Before urea was synthesized, it was generally believed that the scientific principles of non-living substances were not applicable to living bodies, and that only living bodies could produce the molecules that make up living bodies (ie organic molecules). Until 1828, the chemist Friedrich Weiler successfully synthesized the organic molecule urea, proving that organic molecules can also be synthesized. [1] 
Biochemical research began in 1883, and Anselme Payen discovered the first enzyme, amylase. In 1896, Edward Bishner explained a complex biochemical process: the ethanol fermentation process in yeast cell extract. The term "biochemistry" was already used in 1882; but it was not until 1903 when the German chemist Carl Neuberg used it that the term "biochemistry" was widely accepted. Subsequent development of biochemistry, especially since the mid-20th century, with the emergence of various new technologies, such as chromatography, X-ray crystallography, nuclear magnetic resonance, radioisotope labeling, electron microscopy and molecular dynamics simulation, biochemistry With great development. These technologies make it possible to study many biomolecular structures and cellular metabolic pathways, such as glycolysis and tricarboxylic acid cycle. [1] 
Another important historical event in the history of biochemistry is the discovery of a gene and its role in transmitting genetic information in cells; in biochemistry, the part related to it is often called molecular biology. In the 1950s, James Watson, Francis Creek, Rosalyn Franklin, and Morris Wilkins participated in the analysis of the DNA double helix structure and proposed the relationship between DNA and genetic information transmission. [1] 
By 1958, George Wells Biddle and Edward Laurie Tatum won the Nobel Prize in Physiology and Medicine of the year for discovering that "one gene produces one enzyme". In 1988, Colin Pitchfork became the first murderer to be sentenced based on the results of DNA fingerprint analysis. DNA technology has further developed forensic medicine. In 2006, Andrew Faue and Craig Mello won the Nobel Prize for discovering the silencing effect of RNA interference on gene expression. [1] 
The three main branches of biochemistry: general biochemistry research includes the ubiquitous biochemical phenomena in animals and plants; plant biochemistry mainly studies the specific biochemical processes of autotrophic organisms and other plants; and human or pharmaceutical biochemistry focuses on humans and human diseases Related biochemical properties. [1]

Material composition
Organisms are organized by certain material components according to strict rules and methods. The human body contains about 55-67% water, 15-18% protein, 10-15% lipid, 3-4% inorganic salt and 1-2% sugar. From this analysis, apart from water and inorganic salts, the human body is mainly composed of three types of organic substances: protein, lipids and sugars. In fact, in addition to these three categories, there are nucleic acids and a variety of biologically active small molecule compounds, such as vitamins, hormones, amino acids and their derivatives, peptides, and nucleotides. In terms of molecular types, it is more complicated. Taking protein as an example, it is estimated that there are no less than 100,000 protein molecules in the human body. These protein molecules are rarely the same as those in other organisms. Each type of organism has its own unique set of proteins. These are large and complex molecules. Other large and complex molecules include nucleic acids, sugars, and lipids; although their molecular types are not as many as proteins, they are also quite impressive. These large and complex molecules are called "biomolecules". The organism is not only composed of various biological molecules, but also composed of various small molecules with biological activity, which shows the diversity and complexity of the composition of the organism.
Large and complex biomolecules can also be degraded to a very simple level in the body. When biomolecules are hydrolyzed, the basic units that make up them can be found, such as amino acids in proteins, nucleotides in nucleic acids, fatty acids in lipids, and monosaccharides in sugars. These small and simple molecules can be regarded as the building blocks of biological molecules, or called "building block molecules". There are not many of them, and they are basically the same in every kind of organism. In fact, the biomolecules in the living body are only made up of several kinds of building block molecules connected by covalent bonds. Due to the large number of building block molecules that make up a biomolecule, its molecules are large; because there are more than one building block molecules, and the arrangement order can be various, the structure of the resulting biomolecules is of course complicated . Not only that, some biomolecules will have different three-dimensional structures under different circumstances. There are many types of biomolecules. Among the more than 1.3 million kinds of organisms in nature, it is estimated that there are about a kind of protein and a kind of nucleic acid; they are all composed of some building blocks. In the metabolism of organisms, the building block molecules are connected to each other according to certain organization rules, and gradually form biomolecules, subcellular structures, cellular tissues or organs, and finally form a living whole under the communication and connection of nerves and body fluids.

Material metabolism
There are many chemical reactions in the organism, which continue to proceed in accordance with certain rules. If one of the reactions is too much or too little, it will be abnormal, even disease. Except for viruses, viruses have no life reaction under natural environment. Molecules and ions participating in various chemical reactions in organisms are not only biomolecules, but more and more important are small molecules and ions. Some people think that without the participation of small molecules and ions, biomolecules that cannot move or have inconvenience cannot produce various life-critical biochemical reactions. Without small molecules such as adenosine diphosphate (ADP) and adenosine triphosphate (ATP) as a medium for energy reception, storage, transport and supply, the energy released by catabolism in the body will be dissipated as heat and wasted, resulting in all physiological Activities and anabolism cannot be performed. Furthermore, without the presence of ions, ions, and plasmas, many chemical reactions in the body will not occur. With various chemical reactions, organisms can transform, absorb, and use substances (nutrients) and energy in the environment. After entering the body, nutrients are always mixed with the original ones in the body to participate in chemical reactions. In the synthesis reaction, it is used as a raw material to enable various structures in the body to grow, develop, repair, replace and reproduce. In the decomposition reaction, it is mainly used as an energy substance. It releases energy through biological oxidation for the needs of life activities. At the same time, it generates waste, is discharged from the body through various excretion pathways, and is returned to the environment. This is the material exchange process between the organism and its external environment. , Commonly known as material metabolism or metabolism. It is estimated that during a person's life (calculated at the age of 60), the substances exchanged with the in-vitro environment through substance metabolism are approximately equivalent to 60,000 kg of water, 10,000 kg of sugars, 1600 kg of protein and 1000 kg of lipids.
The regulation and control of material metabolism is an important aspect of organisms to maintain life. Most chemical reactions in substance metabolism are caused by enzymes in the cells, and have a high degree of automatic regulation and control. This is one of the important characteristics of biology. In a small living cell, nearly two thousand kinds of enzymes, at the same time, catalyze the unique chemical reactions in various metabolisms. These chemical reactions do not interfere with each other, do not interfere with each other, each proceeding in an orderly manner at an alarming speed, and also cooperate with each other. As a result, both anabolism and catabolism are always carried out just right. Taking protein as an example, artificial synthesis, even if there are many advanced chemists, in a well-equipped laboratory, it can take months or even years to synthesize a protein. However, in a living cell, at 37 ℃ and near neutral environment, a protein molecule can be synthesized in just a few seconds, and there are hundreds of thousands of different protein molecules, almost like the same As in the reaction flask, the synthesis is being performed at the same time, and the speed and amount of synthesis are just in line with the needs of the organism. This shows that there must be perfect arrangements and a regulation control system for the metabolism of substances in the organism. According to existing knowledge, the existence of strict specificity of enzymes, multi-enzyme systems, and regionalization of enzyme distribution may be an explanation for the different metabolic energy in an orderly manner in a cell. In terms of regulation and control, in the animal body, in addition to the important role of neurohumoral fluids, the supply and delivery of agents, product needs and feedback inhibition, gene regulation of enzyme synthesis, enzyme activity is affected by changes in enzyme structure and cofactors Factors such as the richness and lack of influence cannot be ignored.

Structure and function
Each part that constitutes an organism has its special physiological function. From the perspective of biochemistry, it is necessary to deeply explore the functions of cells, subcellular structures and biomolecules. Function comes from structure. To understand the function of a cell, you must first understand its subcellular structure; in the same way, to know the function of a subcellular structure, you must first understand the biological molecules that constitute it. Knowledge about the close relationship between the structure and function of biomolecules is already known. For example, there are many proteins in the cell that have the function of biocatalysts-enzymes; their catalytic activity is closely related to the structure of the active center of their molecules, and at the same time, their specificity is closely related to the structure of their targets; and an allosteric enzyme Activity, in some cases, is also related to the structure of the end products of the metabolic pathways it catalyzes. As another example, the structure of DNA in the nucleus is closely related to its role in genetics; in short, the different nucleotide sequence in DNA shows different information in genetics, which is actually different genes. molecular biology.
In biochemistry, the research on the relationship between structure and function is just beginning; there are many problems that need to be vigorously studied. Among them, the major ones are the combination of biomolecules in subcellular structures, the mutual recognition of similar cells, and the inhibition of cell contact. , Cell adhesion, antigenicity, the role of antigens and antibodies, hormones, nerve mediators and drug receptors.