Biotechnology

All protein molecules are long folded chains of smaller molecules calles amino acids. One of smaller proteins, insulin, contains more than 50 amino acids. The number, types and arrangement of amino acids in a protein molecule determine its structure, and its structure determine the job it will do in a living organism.

DNA is built up by repeating subunits of three linked molecules:base, sugar and phosphate. These units named necleotides are fundamental components of DNA. Because there are four different bases, there are four different kinds of nucleotides.

A protein molecule is made by a gene in two stages. First an RNA copy of gene is made. Transcribed from a template of DNA, the RNA copy has a nucleotide sequence complementing that of gene. Then the RNA move to another part of the cell, where its nucleotide sequence is translated into a sequence of aminoacids to build a protein.