Translation is the process that takes the information passed from DNA as messenger RNA and turns this into a series of amino acids bound together with peptide bonds. It really is a translation from one code, nucleotide sequence, to another code, amino acid sequence. The ribosome is the site of this action, just as RNA polymerase was the site of mRNA synthesis. The ribosome matches the base sequence on the mRNA in sets of three bases (called codons) to tRNA molecules that have the three complementary bases in their anticodon regions. Again, the base pairing rule is important in this recognition (A binds to U and C binds to G). The ribosome moves along the mRNA, matching 3 base pairs at a time and adding the amino acids to the polypeptide chain. When the ribosome reaches one of the "stop" codes, the ribosome releases both the polypeptide and the mRNA. This polypeptide will twist into its native coformation and begin to act as a protein in the cells metabolism. This may be a binding protein, an enzyme, a membrane channel or transport site, or part of the electron transport chain. This description is for the simplest case such as some examples of bacterial protein synthesis. Eukaryotic cells follow these steps but other control steps and modifications are common.
The steps in translation are:
the ribosome binds to mRNA at a specific area
the ribosome starts matching tRNA anticodon sequences to the mRNA codon sequence
each time a new tRNA comes into the ribosome, the amino acid that it was carrying gets added to the elongating polypeptide chain
the ribosome continues until it hits a stop sequence, then it releases the polypeptide and the mRNA
the polypeptide forms into its native shape and starts acting as a functional protein in the cell
