Changes

Watson and Crick suggested that DNA could unzip itself into two separate strands, and each strand could act as a pattern to grow a new strand. Crick showed later that each pair of genes worked in a group of three making the code for amino acids, the building blocks of proteins. These groups are called [[codon|codons]]. They make about fifty thousand different types of [[protein]], which make all the different types of cell in the body. Indian biochemist [[Har Gobind Khorana]] made all the possible codons and worked out which codons controlled which [[amino acid]].  

Watson and Crick suggested that DNA could unzip itself into two separate strands, and each strand could act as a pattern to grow a new strand. Crick showed later that each pair of genes worked in a group of three making the code for amino acids, the building blocks of proteins. These groups are called [[codon|codons]]. They make about fifty thousand different types of [[protein]], which make all the different types of cell in the body. Indian biochemist [[Har Gobind Khorana]] made all the possible codons and worked out which codons controlled which [[amino acid]].  

If the DNA in one cell was stretched out, it would be about three feet long. Although DNA has a very simple structure, it can carry an enormous amount of information. Scientists do not yet understand all the DNA they see, but in 1991 a project called the [[Human Genome Project]] began to use computers to map the three billion base pairs which make up the 46 human [[chromosome|chromosomes]].

If the DNA in one cell was stretched out, it would be about three feet long. Although DNA has a very simple structure, it can carry an enormous amount of [[information]]. Scientists do not yet understand all the DNA they see, but in 1991 a project called the [[Human Genome Project]] began to use computers to map the three billion base pairs which make up the 46 human [[chromosome|chromosomes]].

==Modern understanding==

==Modern understanding==