Canal-U

1.3. DNA codes for genetic information

Remember at the heart of any cell,there is this very long molecule which is called a macromolecule for this reason, which is the DNA molecule. Now we will see that DNA molecules support what is called the "genetic information". So, DNAcodes for genetic information. How? If you consider this doublestrand molecule, DNA molecule, you remember that on each strandof the molecule, there is a succession of nucleotides. You can follow these nucleotides and write their name or moreexactly the initial of their name. And you will get what we call the sequence". Look: C, T, A and so on. The process by which you obtain this sequence of characters of letters from the DNA moleculesis called "sequencing". This is a biochemical object. This is a symbolic object which canbe analysed by computer algorithms. Some points of vocabulary here. What is a genome? The genome is,at the same time, first the DNA molecule itself as thesupport of genetic information. This DNA molecule can be organized into chromosome, plasmid, segment and so on. It means thatmost of the time, it is not in one piece only, but in severalpieces, several chromosomes, plasmids, segments and so on.