The process whereby genes form proteins is very complex and controlled within each cell. Through 2 major steps, known as transcription and translation, specific protein structures are formed. Gene expression takes place through the combined actions of transcription and translation.
The process of transcription takes place in the cell nucleus, where the information stored in the DNA of a gene is transferred to a similar molecule known as RNA (ribonucleic acid). The type of RNA that contains the information to make up a protein is called a messenger RNA (mRNA). This information is carried by the RNA, from the DNA, out of the nucleus of the cells into the cytoplasm.
The process of translation now takes place in the cell’s cytoplasm, when the mRNA interacts with a ribosome. The ribosome “reads and analyses” the sequence of the mRNA code in order to form new proteins from the amino acids. A new type of RNA – transfer RNA (tRNA), now assembles the new protein through controlling the sequence of the amino-acid chains. This process continues until the ribosome gets the code to stop. This flow of information from DNA to RNA to build protein types, is one of the fundamental principles of molecular biology. It is sometimes called the “central dogma.”