What is biological chemistry. What is biochemistry? How to prepare for biochemical analysis

In this article we will answer the question of what biochemistry is. Here we will look at the definition of this science, its history and research methods, pay attention to some processes and define its sections.

Introduction

To answer the question of what biochemistry is, suffice it to say that it is a science devoted to the chemical composition and processes occurring inside a living cell of the body. However, it has many components, having learned which, you can get a more specific idea of ​​it.

In some temporary episodes of the 19th century, the terminological unit “biochemistry” began to be used for the first time. However, it was introduced into scientific circles only in 1903 by a chemist from Germany, Carl Neuberg. This science occupies an intermediate position between biology and chemistry.

Historical facts

Humanity was able to clearly answer the question of what biochemistry is only about a hundred years ago. Despite the fact that society used biochemical processes and reactions in ancient times, it was not aware of the presence of their true essence.

Some of the most distant examples are bread making, winemaking, cheese making, etc. A number of questions about the healing properties of plants, health problems, etc. forced a person to delve into their basis and the nature of the activity.

The development of a general set of directions that ultimately led to the creation of biochemistry can be observed already in ancient times. A scientist-doctor from Persia in the tenth century wrote a book about the canons of medical science, where he was able to describe in detail various medicinal substances. In the 17th century, van Helmont proposed the term "enzyme" as a unit of reactant chemical nature involved in digestive processes.

In the 18th century, thanks to the works of A.L. Lavoisier and M.V. Lomonosov, the law of conservation of mass of matter was derived. At the end of the same century, the importance of oxygen in the process of respiration was determined.

In 1827, science made it possible to create the division of biological molecules into compounds of fats, proteins and carbohydrates. These terms are still used today. A year later, in the work of F. Wöhler, it was proven that substances in living systems can be synthesized by artificial means. One more important event was the production and compilation of a theory of the structure of organic compounds.

The fundamentals of biochemistry took many hundreds of years to form, but were clearly defined in 1903. This science became the first biological discipline that had its own system of mathematical analysis.

25 years later, in 1928, F. Griffith conducted an experiment whose purpose was to study the transformation mechanism. The scientist infected mice with pneumococci. He killed bacteria from one strain and added them to bacteria from another. The study found that the process of purifying disease-causing agents resulted in the formation of nucleic acid rather than protein. The list of discoveries is still growing.

Availability of related disciplines

Biochemistry is a separate science, but its creation was preceded by an active process of development of the organic branch of chemistry. The main difference lies in the objects of study. Biochemistry considers only those substances or processes that can occur in the conditions of living organisms, and not outside them.

Biochemistry eventually incorporated the concept of molecular biology. They differ from each other mainly in their methods of action and the subjects they study. Currently, the terminological units “biochemistry” and “ molecular biology" began to be used as synonyms.

Availability of sections

Today, biochemistry includes a number of research areas, including:

The branch of static biochemistry is the science of the chemical composition of living beings, structures and molecular diversity, functions, etc.

There are a number of sections studying biological polymers of protein, lipid, carbohydrate, amino acid molecules, as well as nucleic acids and the nucleotide itself.

Biochemistry, which studies vitamins, their role and form of influence on the body, possible disturbances in vital processes due to deficiency or excessive amounts.

Hormonal biochemistry is a science that studies hormones, their biological effect, the causes of deficiency or excess.

The science of metabolism and its mechanisms is a dynamic branch of biochemistry (includes bioenergetics).

Molecular Biology Research.

The functional component of biochemistry studies the phenomenon of chemical transformations responsible for the functionality of all components of the body, starting with tissues and ending with the whole body.

Medical biochemistry is a section on the patterns of metabolism between the structures of the body under the influence of diseases.

There are also branches of the biochemistry of microorganisms, humans, animals, plants, blood, tissues, etc.

Research and Problem Solving Tools

Biochemistry methods are based on fractionation, analysis, detailed study and examination of the structure of both an individual component and the whole organism or its substance. Most of them were formed during the 20th century, and chromatography, the process of centrifugation and electrophoresis, became the most widely known.



At the end of the 20th century, biochemical methods began to increasingly find their application in molecular and cellular branches of biology. The structure of the entire genome has been determined human DNA. This discovery made it possible to learn about the existence of a huge number of substances, in particular various proteins, that were not detected during the purification of biomass, due to their extremely low content in the substance.

Genomics has challenged a huge amount of biochemical knowledge and led to the development of changes in its methodology. The concept of computer virtual modeling appeared.

Chemical component

Physiology and biochemistry are closely related. This is explained by the dependence of the rate of occurrence of all physiological processes with the content of a different series chemical elements.



90 components can be found in nature periodic table chemical elements, but about a quarter is needed for life. Our body does not need many rare components at all.

The different positions of a taxon in the hierarchical table of living beings determine different needs for the presence of certain elements.

99% of human mass consists of six elements (C, H, N, O, F, Ca). In addition to the main amount of these types of atoms that form substances, we need 19 more elements, but in small or microscopic volumes. Among them are: Zn, Ni, Ma, K, Cl, Na and others.

Protein biomolecule

The main molecules studied by biochemistry are carbohydrates, proteins, lipids, nucleic acids, and the attention of this science is focused on their hybrids.

Proteins are large compounds. They are formed by linking chains of monomers - amino acids. Most living beings obtain proteins through the synthesis of twenty types of these compounds.

These monomers differ from each other in the structure of the radical group, which plays a huge role during protein folding. The purpose of this process is to form a three-dimensional structure. Amino acids are connected to each other by forming peptide bonds.

When answering the question of what biochemistry is, one cannot fail to mention such complex and multifunctional biological macromolecules as proteins. They have more tasks than polysaccharides or nucleic acids to perform.

Some proteins are represented by enzymes and are involved in catalyzing various reactions of a biochemical nature, which is very important for metabolism. Other protein molecules can act as signaling mechanisms, form cytoskeletons, participate in immune defense, etc.

Some types of proteins are capable of forming non-protein biomolecular complexes. Substances created by fusing proteins with oligosaccharides allow the existence of molecules such as glycoproteins, and interaction with lipids leads to the appearance of lipoproteins.

Nucleic acid molecule

Nucleic acids are represented by complexes of macromolecules consisting of a polynucleotide set of chains. Their main functional purpose is to encode hereditary information. Nucleic acid synthesis occurs due to the presence of mononucleoside triphosphate macroenergetic molecules (ATP, TTP, UTP, GTP, CTP).

The most widespread representatives of such acids are DNA and RNA. These structural elements are found in every living cell, from archaea to eukaryotes, and even viruses.

Lipid molecule

Lipids are molecular substances composed of glycerol, to which fatty acids (1 to 3) are attached through ester bonds. Such substances are divided into groups according to the length of the hydrocarbon chain, and attention is also paid to saturation. The biochemistry of water does not allow it to dissolve lipid (fat) compounds. As a rule, such substances dissolve in polar solutions.



The main tasks of lipids are to provide energy to the body. Some are part of hormones, can perform a signaling function or transport lipophilic molecules.

carbohydrate molecule

Carbohydrates are biopolymers formed by combining monomers that in this case are represented by monosaccharides, such as, for example, glucose or fructose. The study of plant biochemistry has allowed man to determine that the bulk of carbohydrates are contained in them.

These biopolymers find their use in structural function and providing energy resources to an organism or cell. In plant organisms the main storage substance is starch, and in animals it is glycogen.

The course of the Krebs cycle

There is a Krebs cycle in biochemistry - a phenomenon during which the predominant number of eukaryotic organisms receive most of the energy spent on the oxidation processes of ingested food.

It can be observed inside cellular mitochondria. It is formed through several reactions, during which reserves of “hidden” energy are released.

In biochemistry, the Krebs cycle is an important fragment of the general respiratory process and material metabolism within cells. The cycle was discovered and studied by H. Krebs. For this, the scientist received the Nobel Prize.

This process is also called an electron transfer system. This is due to the concomitant conversion of ATP to ADP. The first compound, in turn, is responsible for ensuring metabolic reactions through the release of energy.

Biochemistry and medicine

Biochemistry of medicine is presented to us as a science that covers many areas of biological and chemical processes. Currently, there is an entire industry in education that trains specialists for these studies.

Every living thing is studied here: from bacteria or viruses to the human body. Having a specialty as a biochemist gives the subject the opportunity to follow the diagnosis and analyze the treatment applicable to the individual unit, draw conclusions, etc.



To prepare a highly qualified expert in this field, you need to train him in the natural sciences, medical basics and biotechnological disciplines, conduct many tests in biochemistry. The student is also given the opportunity to practically apply their knowledge.

Universities of biochemistry are currently becoming increasingly popular, which is due to the rapid development of this science, its importance for humans, demand, etc.

Among the most famous educational institutions where specialists in this branch of science are trained, the most popular and significant are: Moscow State University. Lomonosov, Perm State Pedagogical University named after. Belinsky, Moscow State University. Ogarev, Kazan and Krasnoyarsk state universities and others.

The list of documents required for admission to such universities does not differ from the list for admission to other higher education institutions. educational establishments. Biology and chemistry are the main subjects that must be taken upon admission.

BIOCHEMISTRY. Lecture No. 1. Biochemistry as a science. Structure and functions of the main substances in the body. Subject and methods of research in biochemistry. Review of the main classes of organic substances, their role in homeostasis.

Biochemistry (from the Greek βίος - “life” and Egyptian kēme - “Earth”, also biological or physiological chemistry) is the science of the chemical composition of organisms and their components and the chemical processes occurring in organisms. Science deals with the structure and function of substances that are components of cells and make up the body, such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules. Biochemistry seeks to answer biological and biochemical questions using chemical methods.

Biochemistry is a relatively young science that arose at the intersection of biology and chemistry at the end of the 19th century. She studies the processes of development and functioning of organisms in the language of molecules, the structure and chemical processes that ensure the life of single- and multicellular creatures inhabiting the Earth. Outstanding discoveries in the field of enzymes, biochemical genetics, molecular biology and bioenergetics have turned biochemistry into a fundamental discipline that allows solving many important problems of biology and medicine.

Although there is a wide range of different biomolecules, many of them are polymers, i.e. complex large molecules consisting of many similar subunits, monomers. Each class of polymer biomolecules has its own set of types of these subunits. For example, proteins are polymers made of amino acids. Biochemistry studies Chemical properties important biological molecules such as proteins, particularly the chemistry of reactions catalyzed by enzymes.

In addition, most of the research in biochemistry deals with cell metabolism and its endocrine and paracrine regulation. Other areas of biochemistry include the study of the genetic code of DNA and RNA, protein biosynthesis, transport across biological membranes, and signal transduction.

The foundations of biochemistry were laid in the mid-19th century, when scientists such as Friedrich Violer and Anselm Paen were able to describe for the first time the chemical processes in living organisms and show that they are no different from ordinary chemical processes. Many works at the beginning of the 20th century led to an understanding of the structure of proteins, making it possible to carry out bio chemical reactions(alcoholic fermentation) outside the cell, etc. At the same time, the term “biochemistry” itself began to be used. The foundations of biochemistry in Ukraine were laid by Vladimir Ivanovich Vernadsky in the 20s of the last century.

Story

By the beginning of the 19th century there was a general belief that life was not subject to physical and chemical laws inherent in inanimate nature. It was believed that only living organisms are capable of producing molecules characteristic of them. It was only in 1828 that Friedrich Wöhler published work on the synthesis of urea, carried out in laboratory conditions, proving that organic compounds can be created artificially. This discovery dealt a serious defeat to vitalist scientists who had denied this possibility.

By that time, factual material already existed for primary biochemical generalizations, which accumulated in connection with the practical activities of people aimed at making food and wine, obtaining yarn from plants, cleaning the skin from wool with the help of microbes, studying the composition and properties of urine and other secretions healthy and sick person. After Wehler's work, scientific concepts such as respiration, fermentation, fermentation, and photosynthesis gradually began to be established. The study of the chemical composition and properties of compounds isolated from animals and plants becomes the subject of organic chemistry (chemistry of organic compounds).

The birth of biochemistry was also marked by the discovery of the first enzyme, diastase (now known as amylase) in 1833 by Anselm Paen. The difficulties associated with obtaining enzymes from tissues and cells were used by proponents of vitalism to argue that it was impossible to study cellular enzymes outside living beings. This statement was refuted by the Russian physician M. Manasseina (1871 - 1872), who proposed the possibility of observing alcoholic fermentation in extracts of ground (i.e., lacking structural integrity) yeast. In 1896, this possibility was confirmed by the German scientist Eduard Buchner, who was able to experimentally recreate this process.

The term “biochemistry” itself was first proposed in 1882, but it is believed that it gained widespread use after the work of the German chemist Carl Neuberg in 1903. By that time, this field of research was known as physiological chemistry. After this time, biochemistry developed rapidly, especially from the mid-20th century, primarily through the development of new techniques such as chromatography, X-ray diffraction, NMR spectroscopy, radiolabeling, electron and optical microscopy, and finally molecular dynamics and other computational techniques. biology. These methods allowed the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle.

Other important historical event in the development of biochemistry was the discovery of genes and their role in the transmission of information in the cell. This discovery laid the possibility of the emergence not only of genetics, but also of its interdisciplinary branch at the intersection with biochemistry - molecular biology. In the 1950s, James Watson, Francis Crick, Rosalind Franklin and Maurice Wilkins were able to decipher the structure of DNA and suggested its connection with the genetic transmission of information in the cell. Also in the 1950s, George Otley and Edward Tatum proved that a single gene is responsible for the synthesis of a single protein. With the development of DNA analysis techniques such as genetic fingerprinting, in 1988 Colleen Pitchfork became the first person to be charged with murder using DNA evidence, marking the first major success of biochemical forensics. In the 200s, Andrew Fire and Craig Mello showed the role of RNA interference (RNAi) in suppressing gene expression.

Currently, biochemical research is proceeding in three directions, formulated by Michael Sugar. Plant biochemistry studies the biochemistry of predominantly autotrophic organisms and studies processes such as photosynthesis and others. General biochemistry includes the study of plants, animals and humans, while medical biochemistry focuses primarily on human biochemistry and abnormalities in biochemical processes, particularly as a result of disease.

Blood biochemistry is one of the most common and informative tests that doctors prescribe when diagnosing most diseases. Seeing its results, one can judge the state of operation of all body systems. Almost every disease is reflected in the indicators of a biochemical blood test.

What you need to know

Blood is taken from a vein on the elbow, less often from veins on the hand and
forearm.

About 5-10 ml of blood is drawn into the syringe.

Later, the blood for biochemistry in a special test tube is placed in a specialized device that has the ability to determine the necessary indicators with high accuracy. It should be kept in mind that various devices may have slightly different normal limits for certain indicators. The results will be ready within a day using the express method.

How to prepare

Biochemical research is carried out in the morning on an empty stomach.

Before donating blood, you must refrain from drinking alcohol for 24 hours.
The last meal should be the night before, no later than 18.00. Do not smoke two hours before the test. Also avoid intense physical activity and, if possible, stress. Preparing for analysis is a responsible process.

What is included in biochemistry

There are basic and advanced biochemistry. It is not practical to define every indicator possible. It goes without saying that the price and quantity of blood required for analysis increases. There is a certain conditional list of basic indicators that are almost always assigned, and there are many additional ones. They are prescribed by a doctor depending on the clinical symptoms and purpose of the study.

The analysis is done using a biochemical analyzer, into which test tubes with blood are placed

Basic indicators:

1. Total protein.
2. Bilirubin (direct and indirect).
3. Glucose.
4. ALT and AST.
5. Creatinine.
6. Urea.
7. Electrolytes.
8. Cholesterol.

Additional indicators:

1. Albumen.
2. Amylase.
3. Alkaline phosphatase.
4. GGTP.
5. Triglycerides.
6. C-reactive protein.
7. Rheumatoid factor.
8. Creatinine phosphokinase.
9. Myoglobin.
10. Iron.

The list is incomplete; there are many more highly targeted indicators for diagnosing metabolism and dysfunctions of internal organs. Now let's look at some of the most common biochemical blood parameters in more detail.

Total protein (65-85 grams/liter)

Displays the total amount of protein in the blood plasma (both albumin and globulin).
It may be increased with dehydration, due to loss of water due to repeated vomiting, intense sweating, intestinal obstruction and peritonitis. It also increases in myeloma and polyarthritis.

This indicator decreases with prolonged fasting and malnutrition, diseases of the stomach and intestines, when the supply of protein is disrupted. In liver diseases, its synthesis is disrupted. Protein synthesis is also impaired in some hereditary diseases.

Albumin (40-50 grams/liter)

One of the plasma protein fractions. With a decrease in albumin, edema develops, up to anasarca. This is due to the fact that albumin binds water. When it decreases significantly, water is no longer retained in the bloodstream and enters the tissues.
Albumin is reduced in the same conditions as total protein.

Total bilirubin (5-21 µmol/liter)

Total bilirubin includes direct and indirect.

All reasons for increased total bilirubin can be divided into several groups.
Extrahepatic - various anemias, extensive hemorrhages, that is, conditions accompanied by the destruction of red blood cells.

Hepatic causes are associated with the destruction of hepatocytes (liver cells) in oncology, hepatitis, and cirrhosis of the liver.

Impaired outflow of bile due to obstruction of the bile ducts by stones or tumor.

With increased bilirubin, jaundice develops, the skin and mucous membranes become jaundiced.

The normal level of direct bilirubin is up to 7.9 µmol/liter. Indirect bilirubin is determined by the difference between total and direct. Most often, its increase is associated with the breakdown of red blood cells.

Creatinine (80-115 µmol/liter)

One of the main indicators characterizing kidney function.

This indicator increases in acute and chronic kidney diseases. Also with increased destruction of muscle tissue, for example, with rhabdomyolysis after extremely intense physical activity. It may be increased in case of disease of the endocrine glands (hyperfunction of the thyroid gland, acromegaly). If a person eats a large amount of meat products, increased creatinine is also guaranteed.

Creatinine below normal has no special diagnostic value. May be reduced in vegetarians and in pregnant women in the first half of pregnancy.

Urea (2.1-8.2 mmol/liter)

Shows the state of protein metabolism. Characterizes the functioning of the kidneys and liver. An increase in urea in the blood can occur when kidney function is impaired, when they cannot cope with its removal from the body. Also with increased breakdown of proteins or increased intake of protein into the body from food.

A decrease in urea in the blood is observed in the third trimester of pregnancy, with a low-protein diet and severe liver disease.

Transaminases (ALT, AST, GGT)

Aspartate aminotransferase (AST)- an enzyme synthesized in the liver. In blood plasma, its content should not normally exceed 37 U/liter in men and 31 U/liter in women.

Alanine aminotransferase (ALT)– just like the AST enzyme, it is synthesized in the liver.
The normal blood level in men is up to 45 units/liter, in women – up to 34 units/liter.

In addition to the liver, a large number of transaminases are found in the cells of the heart, spleen, kidneys, pancreas, and muscles. An increase in its level is associated with the destruction of cells and the release of this enzyme into the blood. Thus, an increase in ALT and AST is possible with pathology of all of the above organs, accompanied by cell death (hepatitis, myocardial infarction, pancreatitis, necrosis of the kidney and spleen).

Gamma-Glutamyltransferase (GGT) participates in the metabolism of amino acids in the liver. Its content in the blood increases with toxic liver damage, including alcohol. The level is also increased in pathologies of the biliary tract and liver. Always increases with chronic alcoholism.

The norm for this indicator is up to 32 U/liter for men, up to 49 U/liter for women.
A low GGT level is usually detected in liver cirrhosis.

Lactate dehydrogenase (LDH) (120-240 units/liter)

This enzyme is found in all tissues of the body and is involved in the energy processes of glucose and lactic acid oxidation.

Increased in diseases of the liver (hepatitis, cirrhosis), heart (heart attack), lungs (heart attack-pneumonia), kidneys (various nephritis), pancreas (pancreatitis).
A decrease in LDH activity below normal is diagnostically insignificant.

Amylase (3.3-8.9)

Alpha amylase (α-amylase) is involved in carbohydrate metabolism, breaking down complex sugars into simple ones.

Acute hepatitis, pancreatitis, and mumps increase enzyme activity. Certain medications (glucocorticoids, tetracycline) may also have an effect.
Amylase activity is reduced in pancreatic dysfunction and toxicosis of pregnant women.

Pancreatic amylase (p-amylase) is synthesized in the pancreas and enters the intestinal lumen, where the excess is almost completely dissolved by trypsin. Normally, only a small amount enters the blood, where the normal rate in adults is no more than 50 units/liter.

Its activity is increased in acute pancreatitis. It can also be increased when taking alcohol and certain medications, as well as in surgical pathology complicated by peritonitis. A decrease in amylase is an unfavorable sign of the pancreas losing its function.

Total cholesterol (3.6-5.2 mmol/l)

On the one hand, an important component of all cells and component many enzymes. On the other hand, it plays an important role in the development of systemic atherosclerosis.

Total cholesterol includes high, low and very low density lipoproteins. Cholesterol is increased in atherosclerosis, dysfunction of the liver, thyroid gland, and obesity.

Atherosclerotic plaque in a vessel is a consequence of high cholesterol

Cholesterol is reduced with a diet that excludes fats, with hyperfunction of the thyroid gland, with infectious diseases and sepsis.

Glucose (4.1-5.9 mmol/liter)

An important indicator of the state of carbohydrate metabolism and the state of the pancreas.
Increased glucose can occur after eating, so the analysis is taken strictly on an empty stomach. It also increases when taking certain medications (glucocorticosteroids, thyroid hormones), and with pancreatic pathology. Constantly elevated blood sugar is the main diagnostic criterion for diabetes mellitus.
Low sugar can occur due to acute infection, fasting, or an overdose of sugar-lowering drugs.

Electrolytes (K, Na, Cl, Mg)

Electrolytes play an important role in the system of transport of substances and energy into the cell and back. This is especially important for the proper functioning of the heart muscle.

Changes both in the direction of increasing and decreasing concentrations lead to disturbances in heart rhythm, even to cardiac arrest.

Electrolyte standards:

• Potassium (K+) – 3.5-5.1 mmol/liter.
• Sodium (Na+) – 139-155 mmol/liter.
• Calcium (Ca++) – 1.17-1.29 mmol/liter.
• Chlorine (Cl-) – 98-107 mmol/liter.
• Magnesium (Mg++) – 0.66-1.07 mmol/liter.

Changes in electrolyte balance are associated with nutritional reasons (impaired intake into the body), impaired renal function, and hormonal diseases. Also, pronounced electrolyte disturbances can occur with diarrhea, uncontrollable vomiting, and hyperthermia.

Three days before donating blood for biochemistry to determine magnesium, you must not take magnesium medications.

In addition, there are a large number of biochemical indicators that are prescribed individually for specific diseases. Before donating blood, your doctor will determine which specific indicators are taken in your situation. The procedural nurse will draw blood, and the laboratory doctor will provide a transcript of the analysis. Normal values ​​are given for an adult. They may be slightly different for children and the elderly.

As you can see, a biochemical blood test is a very great aid in diagnosis, but only a doctor can compare the results with the clinical picture.

Biochemistry is a whole science that studies, firstly, chemical composition cells and organisms, and secondly, the chemical processes that underlie their life activity. The term was introduced into the scientific community in 1903 by a German chemist named Karl Neuberg.

However, the processes of biochemistry themselves have been known since ancient times. And on the basis of these processes, people baked bread and made cheese, made wine and tanned animal skins, treated diseases with the help of herbs, and then medicines. And the basis of all this is precisely biochemical processes.

For example, without knowing anything about science itself, the Arab scientist and physician Avicenna, who lived in the 10th century, described many medicinal substances and their effects on the body. And Leonardo da Vinci concluded that a living organism can only live in an atmosphere in which a flame can burn.

Like any other science, biochemistry has its own methods of research and study. And the most important of them are chromatography, centrifugation and electrophoresis.

Biochemistry today is a science that has made a big leap in its development. For example, it became known that of all the chemical elements on earth, a little more than a quarter is present in the human body. And most of the rare elements, except iodine and selenium, are completely unnecessary for humans to maintain life. But two common elements such as aluminum and titanium have not yet been found in the human body. And it is simply impossible to find them - they are not needed for life. And among all of them, only 6 are those that a person needs every day and it is from them that 99% of our body consists. These are carbon, hydrogen, nitrogen, oxygen, calcium and phosphorus.

Biochemistry is a science that studies such important components of foods as proteins, fats, carbohydrates and nucleic acids. Today we know almost everything about these substances.

Some people confuse two sciences - biochemistry and organic chemistry. But biochemistry is a science that studies biological processes that occur only in a living organism. And here organic chemistry is a science that studies certain carbon compounds, and these include alcohols, ethers, aldehydes and many, many other compounds.

Biochemistry is also a science that includes cytology, that is, the study of a living cell, its structure, functioning, reproduction, aging and death. This branch of biochemistry is often called molecular biology.

However, molecular biology, as a rule, works with nucleic acids, but biochemists are more interested in proteins and enzymes that trigger certain biochemical reactions.

Today, biochemistry is increasingly using the developments of genetic engineering and biotechnology. However, in themselves, these are also different sciences, which each study their own. For example, biotechnology is studying methods of cloning cells, and genetic engineering is trying to find ways to replace a diseased gene in the human body with a healthy one and thereby avoid the development of many hereditary diseases.

And all these sciences are closely interconnected, which helps them develop and work for the benefit of humanity.

Biochemistry is a science that deals with the study of various molecules, chemical reactions and processes occurring in living cells and organisms. A thorough knowledge of biochemistry is absolutely necessary for the successful development of two main areas of biomedical sciences: 1) solving problems of preserving human health; 2) finding out the causes of various diseases and finding ways to effectively treat them.

BIOCHEMISTRY AND HEALTH

The World Health Organization (WHO) defines health as “a state of complete physical, mental and social well-being that is not merely the absence of disease or infirmity.” From a strictly biochemical point of view, an organism can be considered healthy if many thousands of reactions occurring inside cells and in the extracellular environment occur under such conditions and at such speeds that ensure maximum viability of the organism and maintain a physiologically normal (not pathological) state.

BIOCHEMISTRY, NUTRITION, PREVENTION AND TREATMENT

One of the main prerequisites for maintaining health is an optimal diet containing a number of chemical substances; the main ones are vitamins, some amino acids, some fatty acids, various minerals and water. All these substances are of one kind or another of interest both for biochemistry and for the science of rational nutrition. Therefore, there is a close connection between these two sciences. In addition, it can be expected that, as efforts are made to curb rising health care prices, greater emphasis will be placed on maintaining health and preventing disease, i.e. preventive medicine. For example, to prevent atherosclerosis and cancer, it is likely that rational nutrition will become increasingly important over time. At the same time, the concept of rational nutrition should be based on knowledge of biochemistry.

BIOCHEMISTRY AND DISEASES

All diseases are a manifestation of some changes in the properties of molecules and disturbances in the course of chemical reactions and processes. The main factors leading to the development of diseases in animals and humans are given in Table. 1.1. All of them influence one or more key chemical reactions or the structure and properties of functionally important molecules.

The contribution of biochemical research to the diagnosis and treatment of diseases is as follows.

Table 1.1. The main factors leading to the development of diseases. All of them influence various biochemical processes occurring in a cell or the whole organism.

1. Physical factors: mechanical trauma, extreme temperature, sudden changes in atmospheric pressure, radiation, electric shock

2. Chemical agents and drugs: some toxic compounds, therapeutic drugs, etc.

4. Oxygen starvation: blood loss, impaired oxygen-carrying function, poisoning of oxidative enzymes

5. Genetic factors: congenital, molecular

6. Immunological reactions: anaphylaxis, autoimmune diseases

7. Nutritional imbalances: undernutrition, overnutrition

Thanks to these studies, it is possible to 1) identify the cause of the disease; 2) offer a rational and effective treatment path; 3) develop methods for mass examination of the population for the purpose of early diagnosis; 4) monitor the progress of the disease; 5) monitor the effectiveness of treatment. The Appendix describes the most important biochemical tests used to diagnose various diseases. It will be useful to refer to this Appendix whenever we are talking about the biochemical diagnosis of various diseases (for example, myocardial infarction, acute pancreatitis, etc.).

The potential of biochemistry in the prevention and treatment of disease is briefly illustrated by three examples; We'll look at some more examples later in this chapter.

1. It is well known that in order to maintain his health, a person must receive certain complex organic compounds - vitamins. In the body, vitamins are converted into more complex molecules (coenzymes), which play a key role in many reactions occurring in cells. A lack of any vitamin in the diet can lead to the development of various diseases, for example, scurvy with a lack of vitamin C or rickets with a lack of vitamin D. Determining the key role of vitamins or their biologically active derivatives has become one of the main problems that biochemists and nutritionists have solved since the beginning this century.

2. A condition known as phenylketonuria (PKU) can lead to severe mental retardation if left untreated. The biochemical nature of PKU has been known for about 30 years: the disease is caused by a deficiency or complete absence of the activity of an enzyme that catalyzes the conversion of the amino acid phenylalanine into another amino acid, tyrosine. Insufficient activity of this enzyme leads to the accumulation of excess phenylalanine and some of its metabolites, in particular ketones, in the tissues, which adversely affects the development of the central nervous system. nervous system. After the biochemical basis of PKU was clarified, a rational method of treatment was found: sick children are prescribed a diet with a reduced content of phenylalanine. Mass screening of newborns for PKU allows, if necessary, to begin treatment immediately.

3. Cystic fibrosis is an inherited disease of the exocrine glands, and in particular the sweat glands. The cause of the disease is unknown. Cystic fibrosis is one of the most common genetic diseases in North America. It is characterized by abnormally viscous secretions that clog the pancreatic secretory ducts and bronchioles. Those suffering from this disease most often die at an early age from a pulmonary infection. Since the molecular basis of the disease is unknown, only symptomatic treatment is possible. However, one can hope that in the near future, with the help of recombinant DNA technology, it will be possible to clarify the molecular nature of the disease, which will make it possible to find more effective method treatment.

FORMAL DEFINITION OF BIOCHEMISTRY

Biochemistry, as the name suggests (from the Greek bios-life), is the chemistry of life, or, more strictly, the science of chemical principles life processes.

The structural unit of living systems is the cell, so another definition can be given: biochemistry as a science studies the chemical components of living cells, as well as the reactions and processes in which they participate. According to this definition, biochemistry covers broad areas of cell biology and all of molecular biology.

TASKS OF BIOCHEMISTRY

The main task of biochemistry is to achieve a complete understanding of molecular level the nature of all chemical processes associated with the life of cells.

To solve this problem, it is necessary to isolate from cells the numerous compounds that are found there, determine their structure and establish their functions. As an example, we can point to numerous studies aimed at elucidating the molecular basis of muscle contraction and a number of similar processes. As a result, many compounds of varying degrees of complexity were isolated in purified form and detailed structural and functional studies were carried out. As a result, it was possible to clarify a number of aspects of the molecular basis of muscle contraction.

Another task of biochemistry is to clarify the question of the origin of life. Our understanding of this exciting process is far from comprehensive.

AREAS OF RESEARCH

The scope of biochemistry is as wide as life itself. Wherever life exists, various chemical processes occur. Biochemistry deals with the study of chemical reactions occurring in microorganisms, plants, insects, fish, birds, lower and higher mammals, and in particular in the human body. Of particular interest to students studying biomedical sciences are

the last two sections. However, it would be short-sighted to have no idea at all about biochemical features some other forms of life: often these features are essential for understanding various kinds of situations that are directly related to humans.

BIOCHEMISTRY AND MEDICINE

There is a broad two-way relationship between biochemistry and medicine. Thanks to biochemical research, it was possible to answer many questions related to the development of diseases, and the study of the causes and course of development of some diseases led to the creation of new areas of biochemistry.

Biochemical studies aimed at identifying the causes of diseases

In addition to those mentioned above, we will give four more examples to illustrate the breadth of the range of possible applications of biochemistry. 1. Analysis of the mechanism of action of the toxin produced by the causative agent of cholera made it possible to find out important points in relation to the clinical symptoms of the disease (diarrhea, dehydration). 2. Many African plants have very low levels of one or more essential amino acids. The identification of this fact made it possible to understand why those people for whom these plants are the main source of protein suffer from protein deficiency. 3. It has been discovered that mosquitoes that carry malaria pathogens can develop biochemical systems that make them immune to insecticides; this is important to consider when developing malaria control measures. 4. Greenland Eskimos consume large quantities of fish oil, rich in some polyunsaturated fatty acids; at the same time, it is known that they are characterized by a low level of cholesterol in the blood, and therefore they are much less likely to develop atherosclerosis. These observations suggested the possibility of using polyunsaturated fatty acids to reduce cholesterol in the blood plasma.

The study of diseases contributes to the development of biochemistry

Observations of the English physician Sir Archibald Garrod back in the early 1900s. A small group of patients suffering from inborn errors of metabolism has stimulated research into the biochemical pathways that are disrupted in these conditions. Attempts to understand the nature of a genetic disease called familial hypercholesterolemia, which leads to the development of severe atherosclerosis at an early age, have contributed to the rapid accumulation of information about cellular receptors and the mechanisms of cholesterol uptake by cells. Intensive study of oncogenes in cancer cells has drawn attention to the molecular mechanisms of cell growth control.

Study of lower organisms and viruses

Valuable information, which turned out to be very useful for conducting biochemical research in the clinic, was obtained from the study of some lower organisms and viruses. For example, modern theories regulation of gene and enzyme activity was formed on the basis of pioneering studies performed on molds and bacteria. Recombinant DNA technology originated from research conducted on bacteria and bacterial viruses. The main advantage of bacteria and viruses as objects of biochemical research is their high rate of reproduction; this greatly facilitates genetic analysis and genetic manipulation. Information obtained from studying viral genes responsible for the development of certain forms of cancer in animals (viral oncogenes) has made it possible to better understand the mechanism of transformation of normal human cells into cancer cells.

BIOCHEMISTRY AND OTHER BIOLOGICAL SCIENCES

The biochemistry of nucleic acids lies at the very basis of genetics; in turn, the use of genetic approaches has proven fruitful for many areas of biochemistry. Physiology, the science of how the body functions, overlaps greatly with biochemistry. Used in immunology big number biochemical methods, and in turn many immunological approaches are widely used by biochemists. Pharmacology and pharmacy are based on biochemistry and physiology; Most drugs are metabolized by appropriate enzymatic reactions. Poisons affect biochemical reactions or processes; these questions constitute the subject of toxicology. As we have already said, basically different types Pathology is a violation of a number of chemical processes. This leads to the increasingly widespread use of biochemical approaches to study various types pathologies (for example, inflammatory processes, cell damage and cancer). Many of those involved in zoology and botany make extensive use of biochemical approaches in their work. These relationships are not surprising, since, as we know, life in all its manifestations depends on a variety of biochemical reactions and processes. The barriers that previously existed between the biological sciences have been virtually destroyed, and biochemistry is increasingly becoming their common language.