Question

Discuss the process of translation in detail.

Answer 1

Hint: The principle of central dogma describes how DNA makes its own copies by DNA replication, then codes for the RNA through transcription, and then RNA codes for proteins via translation.

Complete answer:
The translation is a process of translating the mRNA sequence (messenger RNA) into the sequence of amino acids, and this process of translation takes place during protein synthesis. In the process, the ribosome translates the mRNA produced from the DNA into a chain of amino acids, and this chain of amino acids leads to protein synthesis. In this process, the expense of ATP is required and this energy is given by the charged tRNA (transfer RNA). The whole mechanism of translation is present in the ribosome which consists of a larger and a smaller subunit.
The process involves the transport of amino acids to the ribosome where they are assembled in the polypeptide chain. After that, they will assemble into the proteins somewhere in the cytoplasm, and this process is accomplished by the tRNA and occurs in several steps.
Major steps are:
-Activation of amino acids: When an amino acid and ATP are mediated by an aminoacyl synthetase enzyme then the enzyme complex AMP is formed.
-Transfer of amino acid to tRNA: The enzyme complex AMP now reacts with specific tRNA. As a result, an amino acid is transferred into the tRNA molecule and the enzyme and AMP are liberated.
-Initiation of polypeptide chain: The charged tRNA molecule now moves to the ribosome. In presence of an initiation factor, it begins in the five prime ends of mRNA. The mRNA binds with the small subunit of the ribosome while the large subunit binds with the small subunit to complete the initiation complex. Two binding sites of large subunits are aminoacyl tRNA (site A) and peptidyl site (site P).
-Elongation: First codon mRNA binds with is anticodon of methionyl tRNA complex in P-site. Aminoacyl tRNA complex with other amino acids enters the ribosome and attaches with A-site. A peptide bond is formed between the first and second amino acids when anticodon binds to the second codon in mRNA in presence of peptidyl transferase enzyme.
 After this translocation occurs i.e. when the first amino acid and tRNA are broken this tRNA is removed from P-site and the second tRNA from the A-site is pulled to the P-site along with the mRNA.
-Termination: The termination step is signalled by one of the three-terminal codons i.e. UAG, UGA, UAA. Polypeptide chain, tRNA, and mRNA are released out after signaling and the ribosome subunits will dissociate.

Note: Translation describes the process by which mRNA codes for a specific protein. The relationship between the sequence of base pairs and the corresponding amino acids which encodes express the genetic code.