Translation refers to the process of polymerisation of amino acids to form a polypeptide. Ribosome is the site of protein synthesis. The amino acids are joined by a bond which is known as a peptide bond. Formation of a peptide bond requires energy. Therefore, in the first phase itself amino acids are activated in the presence of $ATP$ and linked to their respective $tRNA$-a process commonly called as activaton or charging of $tRNA$ or aminoacylation of $tRNA$ to be more specific.

If two such charged $tRNAs$ are brought close enough, the formation of peptide bond between them would be favoured energetically. The presence of a catalyst would enhance the rate of peptide bond formation. The cellular factory responsible for synthesising proteins is the ribosome. The ribosome consists of structural $RNAs$ and about $80$ different proteins. In its inactive state, it exists as two subunits; a large subunit and a small subunit.

When the small subunit encounters an $mRNA$, the process of translation of the $mRNA$ to protein begins. There are two sites in the large subunit, for subsequent amino acids to bind to and thus, be close enough to each other for the formation of a peptide bond. The ribosome also acts as a catalyst ($23S$ $rRNA$ in bacteria is the enzyme- ribozyme) for the formation of peptide bond or polyribonucleotides.

A translational unit in $mRNA$ is the sequence of $RNA$ that is flanked by the start codon ($AUG$) and the stop codon and codes for a polypeptide. An $mRNA$ also has some additional sequences that are not translated and are referred as untranslated regions ($UTR$). The $UTRs$ are present at both $5^{\prime}$ – end (before start codon) and at $3^{\prime}$ – end (after stop codon). They are required for efficient translation process.

For initiation, the ribosome binds to the $mRNA$ at the start codon ($AUG$) that is recognised only by the initiator $tRNA$. The ribosome proceeds to the elongation phase of protein synthesis. During this stage, complexes composed of an amino acid linked to $tRNA$, sequentially bind to the appropriate codon in $mRNA$by forming complementary base pairs with the $tRNA$ anticodon. The ribosome moves from codon to codon along the $mRNA.$