Translation

Introduction to Translation

  • Translation is the process of converting the information in messenger RNA (mRNA) into a string of amino acids that make up a protein.
  • It is the second part of the central dogma of molecular biology: DNA→RNA→protein.
  • This process takes place in the ribosomes of a cell.

Role of tRNA

  • Transfer RNA (tRNA) plays the key role in the process of translation.
  • Each tRNA molecule consists of a set of three nucleotides known as an anticodon.
  • The anticodon is complementary to the codon sequence on mRNA.

Process of Translation

  • Translation typically proceeds in three stages: Initiation, Elongation, and Termination.
  • Initiation: The ribosome subunits, mRNA, and the first tRNA molecule, holding the first amino acid, come together to form an initiation complex.
  • Elongation: Following initiation, the ribosome travels along the mRNA molecule synthesising the polypeptide as it reads the codons one at a time. New tRNAs carrying the appropriate amino acids bind to each new codon.
  • Termination: Once a stop codon is reached, the process of translation ends, and the newly synthesised protein is released.

Role of Ribosome

  • The ribosome is the site of translation where it binds mRNA and tRNA to synthesise polypeptides and proteins.
  • It has two subunits that close around the mRNA to start the process of translation.

The Genetic Code

  • The genetic code is what determines how the nucleotides in nucleic acids, which are genes, are translated into proteins’ amino acid sequences.
  • It is a set of rules that defines how a triplet codon sequence specifies for a specific amino acid.

Protein Folding

  • Following translation, the polypeptide chain often folds spontaneously into a functional protein.
  • Protein folding is crucial for the protein’s biological function, with correct folding dependent on interactions such as hydrogen bonds and disulphide bridges.

Significance of Translation

  • Translation is a key mechanism for gene expression. Different proteins can be made by translating different parts of the DNA sequence.
  • Through translation, a cell can quickly change the amounts and types of proteins it manufactures, allowing it to react swiftly to changes in its environment.

Errors in Translation

  • Occasionally, errors may occur during translation, causing a faulty protein to be produced, which can potentially lead to diseases.
  • Quality control mechanisms exist to recognise and rectify such mistakes, but when these fail, they can have serious implications.

Please note that this is a simplified overview. The process of translation is complex and involves many more steps and details not covered here.