Introduction to Biochemistry

Biochemistry can be defined as the branch of science that deals with the chemical processes within living organism or concerning living beings. Biochemistry brings biology and chemistry together. Biochemists tries to solve and understand biological problems by using chemical techniques and knowledge. Most of biochemistry deals with the
structures, functions and interactions of biological macro-molecules, such as proteins, carbohydrates and lipids, etc. which provide the structure to cells and perform many important functions associated with life.

There are four main classes of molecules in biochemistry which are:

1.    Carbohydrates,

2.    Lipids,

3.    Proteins,

4.    Nucleic acids

Carbohydrates:

Carbohydrates are essential for life. Most of the energy required for different metabolic activities in an individual is derived from oxidation of carbohydrates. The function of carbohydrates includes energy storage and providing structure. Carbohydrates are composed of molecules containing carbon, hydrogen and oxygen. In carbohydrates the ratio of hydrogen atom to oxygen atom is normally 2:1.

Carbohydrates can be classified into the following:

1.    Monosaccharides: e.g. glucose, fructose.

2.    Oligosaccharides:

I.     Disaccharides: e.g. Sucrose, maltose, lactose etc.

II.    Trisaccharides: e.g. Raffinose

III.   Tetrasaccharides: e.g. Stachyose

3.    Polysaccharides: e.g. Starch, cellulose, glycogen etc.

Lipids:

Lipids or fats can be defined as the ester of fatty acid and glycerol. Fats and lipids can be distinguished by the fact that fats remain solid in ordinary temperature whereas oils remain in liquid state. Lipids are composed of carbon, hydrogen and oxygen atoms like carbohydrates, but the ration of hydrogen to oxygen atoms in higher than 2:1.

Lipids can be classified into:

1.    Simple lipids

2.    Compound lipids

3.    Derived lipids

Amino acids:

Amino acids are small molecules made up of carbon (C), Hydrogen (H), oxygen (O) and nitrogen (N) and also in some cases sulphur (S). There are 20 different amino acids which are alanine, glutamine, glutamic acid, serine, glycine, valine, threonine, cysteine, methionine, lysine, aspartic acid, asparagine, tryptophan, histidine, phenylalanine, tyrosine, proline, arginine, leucine and isoleucine.

Proteins:

Proteins are very large molecules made from amino acids. Some proteins perform largely structural roles. For example, for the contraction of skeletal muscle, the movements of the proteins actin and myosin are responsible.

Nucleic acids:

The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). These nucleic acids are composed of monomeric units called nucleotide. Each nucleotide is composed of three molecules linked together which are a 5-carbon sugar (pentose sugar), an organic base and a phosphoric acid. Both DNA and RNA contain two types of bases, purine and pyrimidine. DNA contains purine, adenine and guanine and pyrimidine, cytosine and thymine whereas RNA contain same purine adenine and guanine but different pyrimidine i.e. cytosine and uracil.

Importance of biochemistry:

1.    Biochemistry is used to understand metabolic processes in plants and animals.

2.    The knowledge of biochemistry is used to substitute biomolecules, such as in the production of artificial sweeteners.

3.    The findings of biochemistry can be applied to medicine, nutrition, and agriculture.

4.    The biochemists investigate the causes and cures of diseases and also study the effects of nutritional deficiencies which is very helpful in medicine.

5.    In agriculture, biochemists investigate soil and fertilizers, and try to discover ways to improve crop cultivation, crop storage and pest control.