Biochemistry is a branch of science which deals with the study of the chemistry of life. This branch of science is a relatively new branch. Biochemistry is a synthetic discipline containing biological sciences and organic chemistry.
Corl Neuberg (1903) first used the term Biochemistry (Greek Bios - life). He defined Biochemistry as science which describes the structure and functioning of living organism in the language of chemistry.
Biochemistry, in its broadest aspects is the most comprehensive of all the branches of chemistry, since it includes organic, inorganic and Physical Biochemistry to the extent to which each of these is related to the chemistry of living things, both the plants and animals.
Biochemistry probes into the chemical changes involved in the origin of the living matter, follows the changes involved in its growth, and studies the processes not only until death but thereafter until dissolution of the matter following its death.
"Biochemistry can be defined as the science concerned with the chemical basis of life. Biochemistry encompasses wide areas of cell biology and molecular biology. To Define Biochemistry it deals with carbon compounds and the reactions they undergo in living organisms."
Introduction to Biochemistry encompasses wide areas of cell biology and molecular biology. It is concerned with the molecules that make up the structure of cells and organs that is molecular anatomy. It deals with carbon compounds and the reactions they undergo in living organisms. It is also concerned with molecular physiology; that is, the functions of molecules in carrying out the needs of the cells and organs.
The beginning of biochemistry is not very marked because this subject is a synthetic discipline comprising biological sciences and Organic Biochemistry. The beginning of research in the area of photosynthesis, respiration, nitrogen metabolism and nucleic acid etc could be appropriately considered as the advent of biochemical age. It has the contribution of many scientists as listed below.
- Louis Pasteur (1860): Louis Pasteur, the well known French scientist did a great deal of work on fermentation and pointed out the central importance of enzymes in this process. He gave the concept of aerobic and anaerobic organisms and their associated fermentation.
- Emil Fischer (1890): Emil Fischer discovered that to fit into the binding site of enzyme a substrate must have a matching shape that is lock and key system of enzyme and substrate molecule. In 1891 his elucidation of the configuration of D-glucose was a remarkable achievement that greatly stimulated the field of organic chemistry. He discovered the process of separation of amino acids from hydrolysates of protein and primary structure of protein.
- Hans Krebs: In 1932 Hans Krebs and Kurt Heneleit proposed urea cycle, it was the first cyclic metabolic pathway to be discovered. In terrestrial vertebrates, urea is synthesized by the urea cycle.
In 1937 Hans Krebs discovered the famous citric acid cycles. In aerobic organisms pyruvic acid is metabolized into CO2, H2O by citric acid cycle.
- Embden, Meyerhof and Parnas (1940): The complete glycolytic pathway was elucidated by the contributions of Gustav Embden, Otto Meyerhof, Carl Neuberg, Jacob Parnas, Otto Warburg, Gery Cori and Carl cori. Glycolysis is also known as the Embden-Meyerhof pathway.
- James Watson and Francis Crick (1953): Watson and Crick proposed the three dimensional model of DNA and immediately later proposed mechanism of DNA replication. This discovery ranks as one of the most significant in the history of biology because it led the way to an understanding of gene function in molecular terms.
- H.Govind Khorana: In 1964 H.G. Khorana succeeded in synthesizing polyribonucleotide with a defined repeating sequence. This polymer was used as a template in the cell free protein synthesis.
By 1966 Khoranaand Nirenberg elucidated the complete genetic code and function of individual codons coding for respective amino acids in protein synthesis.
- Anthony Lavoisier (1743-1794): His classical research on oxidation and the role played by the O2 in the process led him to investigate "burning" in the body and he concluded that oxygen is consumed in reaction, the carbon dioxide is eliminated and heat is evolved. He is also known as the "father of modern biochemistry".
The objectives of biochemistry are listed below.
- To study and understand the structures and properties of substances consisting the framework of cell and tissues.
- To study the structures and properties of substances which enter the cell as sources of energy or leave the cell as waste products.
- To study the catalytic activity of enzymes.
- To study processes that convert diet into compounds which are characteristics of the cells of a given species.
- To study the manifold energy-requiring process of the living cell.
- To study the chemistry of inheritance
Biochemistry is studied to understand the following facts.
The structure and properties of substances constituting the framework of cells and tissues.
The structure and properties of substances which enter the cells as useful working materials or source of energy or leaving the cell as waste products.
The catalytic tasks of enzymes.
The chemical processes which convert diet into compounds which are characteristic of the cells of a given species.
Using the potential energy obtained from the oxidation of food stuffs utilized to drive the manifold energy requiring process of living cell.
Chemistry of inheritance
The molecular basis of life
- In diagnosis
- Discovery of new drugs
- Solving some fundamental problems in biology and medicine
Biochemistry shows that living organisms are composed of similar organic compounds; in particular, proteins nucleic acid. It is also concerned with molecular physiology, that is the functions of molecules in carrying out the needs of the cells and organs. Biochemistry can be broadly classified as:
Biochemistry is an interdisciplinary science that integrates systematically the principles of mathematics, physics and chemistry to attempt to explain the distinctive characteristics of life processes in terms of structure-function correlations.
Advances in biochemistry have therefore largely exploited principles and techniques first applied in the physical sciences. Biochemistry Examples is quintessentially both analytical and quantitative in
using model biological system of different physiological complexities to
explain cause and effect relationship in molecular terms.
Some of the solved problems are given below.
What is the energy requirement of protein biosynthesis? Solution:
The cost of adding one amino acid to a growing polypeptide is four or five high energy bonds to form an ATP during the charging of the transfer RNA, and two or three from the hydrolysis of GTPs during transfer RNA binding to the A site of the ribosome and during translocation. Thus for an average protein of three hundred amino acids, there is a cost of 1,200 to 1,500 high energy bonds.
Why is phenylalanine very poorly soluble in water, while serine is freely water soluble? Solution:
The aromatic side chain of phenylalanine is non polar and its solvation by water is accompanied by a loss of entropy and is therefore unfavorable. On the other hand the side chain of serine carries a polar hydroxyl group that allows hydrogen bonding with water.