Biochemistry (Chemical Constitution)

Sometimes it is impossible to classify organism using morphological criteria, so one resorts to comparing the chemical substance which they contain.
This is particularly useful when classifying organism like bacteria which may all look alike and have an identical cellular structure. Using techniques such as chromatography and electrophoresis, it is possible to compare the amino acid sequence in the proteins of different organism, or the order of bases in their DNA. This is useful not only in classifying organism, but is indispensable when trying to establish evolutionary relationship.

Nucleic Acid

A 22 years old swiss physician and chemist, Friedrich Miescher isolated a substance from the nuclei of Pus Cells, which was quite different from other bio molecules and named it as Nuclein. Later, it was found that the nuclein had acidic properties and hence it was renamed as nucleic acid.

Nucleic acids are present in all organism, from virus to man these macromolecules are present either in the free- state or bound to proteins as nucleoproteins. Like proteins, the nucleic acids are bio polymers of high molecular weight with monomucleotide as their sub-units (monomers). The nucleic acids are the longs chain of poly nucleotide in which mono nucleotide are linked with each other.

Functions of Carbohydrate

Carbohydrates are the potential source of energy. This energy is utilized in body metabolism. Carbohydrates also act as storage food molecules. In plants excess glucose in converted into starch and in animals into glycogen. Carbohydrates also work as an excellent building. Protective and supporting structure e.g : Cellulose is the major component of cell- wall. In animals chitin forms the exoskeleton of arthropods. They also form complex conjugated molecules.

Chemical Compostion of Cell

As we know that all the living bodies are structurally consist of cells and living cell contains a living material called Protoplasm. The actual chemical composition of Protoplasm is still not known perfectly. However, chemically it contains 70 to 90% of H2O. If the water is evaporated, the remaining mass is called dry weight of the cell, which consists of mainly carbon containing molecules, these molecules were termed as organic molecules. As chemist synthesized these molecules in laboratory, the mystery associated with organic compounds disappeared. Now, the compounds produced by living organism are called Biochemical