Kneeling for help.

First, the concept of biochemistry and its research content

The life phenomenon (process) of living organisms as a unique and special form of material movement, and its basic form of expression is (metabolism and self-reproduction). So what is the material basis of this special form of movement? Engels said a long time ago that "proteins are the embodiment of life activities". It is now known that protein alone is not enough, but also nucleic acids, sugars, lipids, vitamins, hormones, terpenes, buchinoline and so on. It is these substances of life between the role of mutual coordination to form a colorful phenomenon of life, then, these substances of life in the end have those? How do they arise and die, and how do they transform and interact with each other? This is the content of biochemistry to study.

So let's try to define biochemistry.

Biochemistry is the science that studies the material composition of living organisms and the chemical changes that occur during life. Or biochemistry is the study of the material basis and chemical changes in the phenomena of life. More simply biochemistry is the study of the chemical nature of the phenomena of life. Some people also claim that biochemistry is the chemistry of life.

Biochemistry is the study of the chemical composition of living matter, and the process of life in a variety of chemical changes in the sub-discipline of biology.

If different organisms as the object, biochemistry can be divided into animal biochemistry, plant biochemistry, microbial biochemistry, insect biochemistry, etc.; if different tissues of organisms or processes as the object of study, can be divided into muscle biochemistry, neurobiochemistry, immune biochemistry, bioenergetics, etc.; due to the study of the material is different, but also can be divided into protein chemistry, nucleic acid chemistry, enzymology, and other branches; the study of natural substances of chemistry is called bio-organic chemistry; the study of natural substances is called bioorganic chemistry. The chemistry of natural substances is called bio-organic chemistry; the study of biological functions of various inorganic substances is called bioinorganic chemistry or inorganic biochemistry.

Since the sixties of the twentieth century, biochemistry and other disciplines have been fused to produce some fringe disciplines, such as biochemical pharmacology, paleochemistry, chemical ecology, etc.; or according to the different fields of application, medical biochemistry, agricultural biochemistry, industrial biochemistry, nutritional biochemistry, and so on.

Two, biochemistry research methods

The above spoke of the object of biochemistry, then modern biochemists all day to do what? Four words; separation and analysis.

Starting from the observation of a specific phenomenon of life, through the extraction, filtration, centrifugation, chromatography (chromatography) and other biochemical techniques to separate an unknown biochemical substances (biochemical components) such as a new unknown protein components, new gene fragments, or new secondary metabolites, and then analyzed,

1. Structure and properties: the use of a series of measurements, X - ray diffraction, spectroscopy, and other methods of biochemistry. -ray diffraction, wave spectroscopy, mass spectrometry, circular dichroism and other techniques to analyze its structure and function, the structure is the basis of the function, there is its structure must have its function.

2. Functions: physiology, pathology, signaling, anti-disease, drought resistance, water and fertilizer resistance, obesity, etc.

3. Metabolism and its cellular regulation: the spatial and temporal specificity of the expression, when the substance is produced and eliminated, and in what tissues it is expressed? Where does it come from and where does it end up, and what is its metabolism regulated by? (latency, activation, silencing).

4 transformation and utilization Understanding the world is to transform the world, through the isolation, analysis after figuring out these phenomena of life, and finally the right medicine: gene therapy: hemophilia, cancer, obesity and so on. Biochemical drugs (genetically engineered drugs): erythropoietin, sulfa drugs. Genetic improvement: anti-insect, anti-disease, anti-virus and so on.

III. A brief history of biochemistry

The term biochemistry appeared around the end of the 19th century and the beginning of the 20th century, but its origins go back much further, and its early history was part of the early history of physiology and chemistry. In the 1880s, for example, Lavoisier demonstrated that respiration was as much an oxidizing process as combustion, and almost simultaneously scientists discovered that photosynthesis was essentially the reverse process of respiration in animals. In 1828, Waller synthesized urea, an organic substance, for the first time in the laboratory, breaking the idea that organic matter can only be produced by living things, and dealing a major blow to the "theory of organisms".

In 1860, Pasteur proved that fermentation is caused by microorganisms, but he believed that there must be a living yeast to cause fermentation. 1897 Bichner brothers found that the yeast cell-free extract can be fermented, proving that there are no living cells can be carried out, such as fermentation of such a complex life activity, and finally overthrew the "theory of organisms.

The development of biochemistry can be roughly divided into three stages.

The first stage, from the end of the 19th century to the 1930s, was mainly a static descriptive stage, in which the various constituents of living organisms were isolated, purified, structurally determined, synthesized, and physicochemical properties were studied. Among them, Fischer determined the structure of many sugars and amino acids, determined the conformation of sugar, and pointed out that proteins are belly-bonded. 1926 Sumner produced urease crystals, and proved that it is protein.

Four or five years thereafter Northrop and others crystallized several enzymes that hydrolyze proteins, pointing out that they are all, without exception, proteins, establishing the concept that enzymes are proteins. A series of vitamins were discovered through food analysis and nutritional studies, and their structures elucidated.

At the same time, another group of substances, hormones, was recognized as being small in quantity but significant in function. Unlike vitamins, they do not depend on an external supply, but are produced by the animal itself and function in itself. Adrenaline, insulin and steroid hormones contained in the adrenal cortex were all discovered at this stage. In addition, the Chinese biochemist Wu Xian introduced the concept of protein denaturation in 1931.

The second phase was around the 1930s to 1950s, mainly characterized by the study of changes in substances in living organisms, i.e., metabolic pathways, so called dynamic biochemical stage. The outstanding achievement during this period was the identification of important catabolic pathways such as glycolysis, the tricarboxylic acid cycle, and lipolysis. A deeper understanding of respiration, photosynthesis, and the key position of adenosine triphosphate (ATP) in energy conversion was gained.

This division of stages is, of course, relative. The understanding of biosynthetic pathways was much later, with the biosynthetic pathways of amino acids, purines, pyridines, and fatty acids only being elucidated in the 1950s and 1960s.

The third phase began in the 1950s and was mainly characterized by the study of the structure and function of biomolecules. The development of biochemistry in this phase, as well as the penetration of other disciplines such as physics, technical sciences, microbiology, genetics, and cytology, gave rise to molecular biology, which became the mainstay of biochemistry.

Basic Contents of Biochemistry

Besides water and inorganic salts, the organic matter of living cells consists mainly of carbon atoms combined with hydrogen, oxygen, nitrogen, phosphorus, and sulfur, and is classified into two main groups: macromolecules and small molecules. The former includes proteins, nucleic acids, polysaccharides and lipids existing in bound state; the latter has vitamins, hormones, various metabolic intermediates, and amino acids, nucleotides, sugars, fatty acids and glycerol required for the synthesis of biomolecules. In different organisms, there are also various secondary metabolites such as terpenes, alkaloids, toxins, and antibiotics.

While the identification of the composition of organisms characterized the early stages of the development of biochemistry, new substances continue to be discovered until today. Such as the successive discovery of interferon, cyclic nucleoside phosphate, calmodulin, adhesion proteins, exogenous lectins, etc., has become an important research topic.

Long-known compounds will also find new functions, carnitine discovered in the early twentieth century, the 50's only know is a growth factor, and to the 60's and understand is a carrier of biological oxidation; for many years was considered to be a decomposition product of the putrescine and cadaverine, and spermine, spermidine and other polyamines have been found to have a variety of physiological functions, such as participation in the regulation of nucleic acid and protein synthesis, on the DNA superhelix, and regulation of cell differentiation.

Metabolism consists of anabolism and catabolism. The former is the process by which organisms obtain substances from the environment and convert them into new substances in the body, also called assimilation; the latter is the process by which the original substances in the organisms are converted into the substances in the environment, also known as anabolism. Both the processes of assimilation and alienation consist of a series of intermediate steps. Intermediate metabolism is the study of the chemical pathways involved.

The process of material metabolism is also accompanied by changes in energy. The interconversion and change of mechanical, chemical, thermal, light, electrical and other energies in an organism is called energy metabolism, and ATP plays a central role in this process. Metabolism is organized under the regulatory control of the organism. The vast majority of regulatory processes in organisms are realized through allosteric effects.

The diverse functions of biomolecules are closely related to their specific structures. The main functions of proteins are catalysis, transportation and storage, mechanical support, locomotion, immune protection, reception and transmission of information, regulation of metabolism and gene expression. As advances in structural analysis techniques have enabled in-depth study of their various functions at the molecular level, the motility within protein molecules is an important basis for their execution of various functions.

Protein engineering, which appeared in the early 1980s, obtains protein molecules that have been modified at specified sites by changing the structural genes of proteins. This technique not only provides a new way to study the relationship between structure and function of proteins; but also opens up a broad prospect of synthesizing new proteins with specific functions according to certain requirements.

The study of the structure and function of nucleic acids has contributed to elucidating the nature of genes and understanding the flow of genetic information in organisms. Base pairing is the primary form of interaction of nucleic acid molecules, which is the structural basis of nucleic acids as information molecules.

The regulatory control of gene expression is a central issue in the study of molecular genetics, as well as an important element in the study of the structure and function of nucleic acids. For the prokaryotic gene regulation has been a lot of understanding; eukaryotic gene regulation is being explored from various aspects. For example, heterochromatinization and chromatin activation; conformational changes and chemical modification of DNA; the role of regulatory sequences such as enhancers and modulators on DNA; and the regulation of RNA processing and translation processes.

The saccharides of living organisms include polysaccharides, oligosaccharides, and monosaccharides. Among polysaccharides, cellulose and chitin are structural substances in plants and animals, and starch and glycogen, among others, are stored nutrients. Monosaccharides are the main source of energy for organisms. The structural and functional importance of oligosaccharides only began to be recognized in the 1970s. Oligosaccharides and proteins or lipids can form glycoproteins, proteoglycans and glycolipids.

The complexity of the structure of sugar chains gives them a large information capacity, which is important for cells to recognize certain substances specifically and interact with each other to affect the cell's metabolism. From the trend of development, sugar will be alongside proteins, nucleic acids, enzymes and become the four major research objects of biochemistry.

Biomolecules can be synthesized in the laboratory once their chemical structures have been determined. The synthetic synthesis of biomolecules and their analogs helps to understand the relationship between their structure and function. Some analogs may have applications due to their higher biological activity. Artificial genes obtained by chemical synthesis of DNA can be applied to genetic engineering to obtain functionally important proteins and their analogs.

Almost all chemical reactions in living organisms are catalyzed by enzymes. The action of enzymes is characterized by high catalytic efficiency and specificity. These characteristics depend on the structure of the enzyme. The relationship between the structure and function of enzymes, reaction kinetics and mechanism of action, and the regulation and control of enzyme activity are the basic contents of enzymology research. Enzymes have a very close relationship with human life and production activities, so the application of enzymes in industrial and agricultural production, national defense and medicine has been widely valued.

Biological membranes are mainly composed of lipids and proteins, and generally also contain sugars, and their basic structure can be expressed by the flow mosaic model, i.e., lipid molecules form a bilayer membrane, and the membrane proteins interact with the lipids to different degrees and can move sideways. Biological membranes are closely related to energy conversion, material and information transmission, cell differentiation and division, nerve conduction, immune response, etc., and are an active research field in biochemistry.

Hormones are important regulators of metabolism. The hormone system and the nervous system constitute the two main communication systems of the organism, and there is a close connection between the two. since the 70's, the scope of hormone research has been expanding, and the chemical structure of many hormones has been determined, and they are mainly peptides and steroidal compounds. The principles of action of some hormones are also understood; some alter permeability, others activate cellular enzyme systems, and still others affect gene expression. Vitamins also have an important effect on metabolism and can be divided into two main groups: water-soluble and fat-soluble. Most of them are cofactors or coenzymes for enzymes and are closely related to the health of the organism.

The theory of biological evolution holds that millions of species on Earth have the same origin and have evolved over a period of about 4 billion years. Advances in biochemistry have provided strong evidence for this doctrine at the molecular level.

In the development of biochemistry, many major advances are due to methodological breakthroughs. since the 1990s, computer technology has been widely and rapidly penetrated into various fields of biochemistry, which has not only greatly increased the degree of automation and efficiency of many analytical instruments, but also provided brand new means for the structural analysis of biological macromolecules, structural prediction, and research on the relationship between structure and function. The future development of biochemistry will undoubtedly benefit from technological and methodological innovations.

The profound influence of biochemistry on other biological disciplines is firstly reflected in the fields of cytology, microbiology, genetics, physiology, etc., which are closely related to it. Through the in-depth study of the structure and function of biological macromolecules, it has revealed many mysteries such as the soundness of living organisms, energy conversion, genetic information transfer, photosynthesis, nerve conduction, muscle contraction, hormone action, immunity and intercellular communication, etc., which has led to a brand-new stage in the understanding of the nature of life.

Some disciplines in biology that seem to have little to do with biochemistry, such as taxonomy and ecology, need to be considered and studied from a biochemical point of view, even when exploring social issues such as population control, world food supply, and environmental protection.

In addition, biochemistry serves as a bridge between biology and physics, presenting the major and complex issues raised in the world of life to physics, giving rise to fringe disciplines such as biophysics and quantum biochemistry, thus enriching the research content of physics and promoting the development of physics and biology.

Biochemistry has grown up under the impetus of production practices in medicine, agriculture, certain industries and the defense sector, and, in turn, it has contributed to the development of production practices in these sectors.

Biochemistry has shown its power in the fermentation, food, textile, pharmaceutical, and leather industries. For example, the tanning of leather, dehairing, silk degumming, cotton sizing are used enzymatically instead of the old process. Modern fermentation industry, biological products and pharmaceutical industry, including antibiotics, organic solvents, organic acids, amino acids, enzymes, hormones, blood products and vaccines, etc. have created a considerable economic value, especially the immobilized enzyme and immobilized cellular technology has been more to promote the development of enzyme industry and fermentation industry.

V. Biochemistry and the twenty-first century life sciences outlook

1, biochemistry and molecular biology is the twenty-first century life sciences leading disciplines. Hot spots of the discipline: genome, proteome, biological cloning

2. Biochemistry and agriculture primitive agriculture: gathering and hunting, nomadic; traditional agriculture: primitive cultivation, animal husbandry; modern agriculture: chemical fertilizers, pesticides; green revolution (hybrid advantage), biological control, molecular breeding. ; molecular agriculture (factory farming): leaving the land, biochemical processing industry at the cellular level or even the molecular level, principle of bionics. ; Plants: photosynthesis → immobilized cell culture, chloroplasts → photosynthesizers. ; Animals: cell culture.

3. Biochemistry and environmental protection. Biopurification:; Biosensing: enzymes, cells, indicator plants;

4. Biochemistry and light industry; Fermentation industry: antibiotics, amino acids. Food industry and feed industry: enzymes, additives, flavorings, tanning and paper industry: bioelectronics: DNA storage.

5. Biochemistry and medicine. Biochemical drugs: vaccines, genetically engineered drugs: gene therapy:

6. Opportunities and Challenges in Biochemistry. (1), Opportunities: the emergence of research tools and research methods; (2), Challenges: many major theoretical problems have not been solved

Photosynthesis, bioenergetics, gene expression and regulation.