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Molecular Basis Of Inheritance

Question
CBSEENBI12001834

How do m-RNA, t-RNA and ribosomes help in the process of translation?

Solution

Translation is the process of polymerising amino acid to form a polypeptide chain.

The triplet sequence of base pairs in mRNA defines the order and sequence of amino acids in a polypeptide chain.

The process of translation involves the following three steps:

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(i) Initiation

(ii) Elongation

(iii) Termination

  • During the initiation of the translation, tRNA gets charged when the amino acid binds to it using ATP.
  • The start (initiation) codon (AUG) present on mRNA is recognised only by the charged tRNA.
  • The ribosome acts as an actual site for the process of translation and contains two separate sites in a large subunit for the attachment of subsequent amino acids.
  • The small subunit of ribosome binds to mRNA at the start codon (AUG) followed by the large subunit. Then, it initiates the process of translation.
  • During the elongation process, the ribosome moves one codon downstream along with mRNA so as to leave the space for binding of another charged tRNA.
  • The amino acid brought by tRNA gets linked with the previous amino acid through a peptide bond and this process continues to result in the formation of a polypeptide chain.
  • When the ribosome reaches one or more stop codon (VAA, UAG and UGA), the process of translation gets terminated.
  • The polypeptide chain is released and the ribosomes get detached from mRNA.