Introduction

Chapter 1

Introduction

Publisher Summary

The aims of biochemistry are to describe the nature of living forms and living processes in terms of chemistry and physics. Biochemists believe that the existence and activities of living organisms are explained on the basis of the interaction of their component molecules. These are divided very broadly into two groups, namely, small molecules and macromolecules. The main types of macromolecule are proteins, nucleic acids, and polysaccharides, all of which are long, chain-like molecules built up from a large number of linked subunits. These biopolymers tend to associate into still larger complexes with other molecules that may or may not be of the same type. The small molecules act not only as the building units from which macromolecules are synthesized but also as sources of energy, messengers, and regulators. Macromolecules are the essential basis of the elaborate structures in and around which the life processes occur; they also control and regulate these processes. Thus, macromolecules are responsible for the energy exchanges and chemical reactions that comprise metabolism for the irritability that enables the organism to respond to changes in its environment, for mobility, and for reproduction. The aims, attitudes, and techniques of biochemistry are as relevant to dentistry as to medicine or any other aspect of biology. Only when the normal structures of the mouth and their development and reactions are understood is it possible to appreciate the true nature of dental disease. All disease has a biochemical basis regardless of whether its origin is nutritional or genetic or it is caused by an infectious or toxic agent.

The scope of biochemistry

The aims of biochemistry are to describe the nature of living forms and living processes in terms of chemistry and physics. Biochemists believe that the existence and activities of living organisms can be explained on the basis of the interaction of their component molecules. These may be divided very broadly into two groups, namely small molecules and macromolecules.

The main types of macromolecule are proteins, nucleic acids and polysaccharides, all of which are long, chain-like molecules built up from a large number of linked subunits. These biopolymers tend to associate into still larger complexes with other molecules which may or may not be of the same type. The small molecules act not only as the building units from which macromolecules are synthesized but also as sources of energy, messengers and regulators. Macromolecules are the essential basis of the elaborate structures in and around which the life processes occur; they also control and regulate these processes. Thus macromolecules are responsible for the energy exchanges and chemical reactions that comprise metabolism, for the irritability which enables the organism to respond to changes in its environment, for mobility and for reproduction.

Since molecules do not function alone but by interaction with other molecules, living processes require specific arrangements of molecules and ‘life’ resolves itself into a question of molecular organization.

This organization is based on certain general principles, e.g.:

In the higher forms of life biological organization falls into a series of levels arranged in a discontinuous order. At each level there appear to be units of a fairly definite size which become associated to form a unit at the next level, and as each successive level of organization is achieved new properties emerge. The levels may be listed as follows:

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Dec 10, 2015 | Posted by in General Dentistry | Comments Off on Introduction
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