Protein Synthesis Apparatus
Protein synthesis takes place under the direction of DNA, which carries the genetic information for primary structure of a protein. This information from DNA is transferred to messenger RNA (mRNA) during a process called transcription
as will be discussed in Expression of Gene : Protein Synthesis 2. Transcription in Prokaryotes and Eukaryotes
. Messenger RNA (mRNA) is then utilized for actual assembly of amino acids in the form of polypeptides through peptide linkages, during a process called translation
(Expression of Gene : Protein Synthesis 4. Translation in Prokaryotes and Eukaryotes
). For this purpose, as will be seen later, an apparatus is needed, which besides a number of enzymes, mainly consists of (i) tRNA and (ii) ribosomes. The detailed structures of tRNA and ribosomes should, therefore, be understood, so that their role in protein synthesis may be appreciated.