Everyone can hear things on TV or read in the newspaper about DNA, and detecting criminals using DNA. But what exactly is DNA? And how is it that all the genetic information in DNA is fixed? How does that information into a protein that actually can do what in the body?

DNA - what is it anyway?

DNA stands for deoxyribonucleic acid. In English it desoxyribonucleic acid, hence the A instead of the Z.

DNA is in every cell in the body, in every human, animal and plant. You can not live without DNA. This is because if it were DNA determines what happens. It does not itself, but do proteins. Which are made to the rules stored in the DNA. How about that?

Discovery

DNA is in the nucleus of every cell and consists of two long beaded necklaces, which are twisted around each other, like a spiral staircase. We call that an α-helix. It is only since 1953 known exactly how they are turned, and Mr Watson and Crick were the first who invented it. Actually it probably was Rosalind Franklin who had the real Eureka moment, but women and science, which at that time was just not so good together and it's mainly the men who got the credits for the work (s).

Structure of DNA

The bead necklaces which DNA is made, consist of four different "beads," which we called nucleotides. A nucleotide consists of three parts, one of the others may vary. This is the base. There are four different bases designated by the letters A, T, G and C, which are abbreviations of the names adenine, thymine, guanine and cytosine. The bead chains are twisted around each other, while there are two bases of the two opposing chains. A is always opposite T and G is always opposite C. These four letters form the alphabet of all the information a cell needs. It seems a small alphabet, but the computer uses only two letters (or rather numbers, 0 and 1) and it works fairly well.

Translating the information into RNA

The alphabet of the DNA is read by RNA polymerase. RNA is a copy of DNA, with a few differences. First, the acronym instead of an R a D, and that is because the full name is ribonucleic acid, there is a small change in one of the three component parts of the beads are made. Furthermore, RNA can leave the nucleus, thus the information from the nucleus to the cell can bring. DNA remains in the nucleus. And RNA consists of A, C, G and U. There is therefore a uracil instead of a thymine. RNA polymerase extracts the two beaded necklaces - strings - from each other where there is a code for "start copying. RNA polymerase is exactly that code (the promoter) are, and start reading. While it does, locate the RNA nucleotides that fit exactly on the DNA. So if there is a G in the DNA, RNA polymerase looks for a C, and if there is an A in DNA locates the RNA polymerase a U. Facing a T is an A and so does the RNA polymerase a long, complementary (opposite) strand. Just until he encounters a code that means "stop copying," then he lets loose DNA and RNA, and DNA strand turns back to himself. The formed strand of RNA called messengerRNA (mRNA for short) because they may leave a core message of the DNA to the rest of the cell.

Translating the information into proteins

If this mRNA in the cytoplasm outside the nucleus, it could still not do much. The information contained in it must first be converted into proteins, which actually can do something. A ribosome, the information of the mRNA into a protein. A ribosome reads not a letter, but by three. Such a piece of three is called a codon. The ribosome is sitting on a codon (eg AUG), and seeks a transferRNA (tRNA). This is a piece of RNA that is exactly the letters 'reverse' - ie an anticodon - and also carries an amino acid. This amino acid is not just a random amino acid, but each has a specific amino acid anticodon with him. If the ribosome tRNA has found the good, he goes one step ahead of three, searching the next appropriate tRNA. The amino acids that these tRNAs bear, stick it together, and he will continue down the mRNA strand. Thus a chain of amino acids, a protein! After a while, the ribosome at a codon that means stopping all let loose, and the protein is finished.

Proteins as the executive staff

Proteins can do things in the cell. They are actually the workers. For example, insulin is a protein that regulates blood sugar. Hemoglobin is a protein that can transport oxygen in the blood.

There is even a mechanism that is passed to the core that enough of a particular protein. This protein is therefore no longer made. You could say that DNA ultimately determines what happens!