Question

process of translation in dna

Answer 1

Answer

• Translation is synthesis of proteins by ribosomes in the cytoplasm or endoplasmic reticulum after the transcription of DNA to RNA in the nucleus.
• In translation, genetic message is carried by messenger RNA and is converted to the form of polypeptide chain having a specific sequence of amino acids.
• The key components of translation are : Ribosomes, transfer RNA and amino acids.
  

There are three steps of translation.

1. Initiation
2. Elongation
3. Termination

Initiation

• Synthesis is initiated with amino acid methronine.
• A tRNA synthase enzyme helps in the process of initiation.
• A sequence of three nucleotides on tRNA complementary to genetic codon on mRNA is called anticodon.
• The genetic code for metheonine on m-RNA is AUG and thus the anticodon on t-RNA is UAC.
• Formyl-methionine acyl t RNA with its amino acid get attached. Thus synthesis of protein is initiated.

Elongation

• Other t-RNA molecules carrying their specific amino acid molecules and processing anticodon specific to the genetic code on m-RNA become sequentially arranged.
• Protein such as elongation factor and GTP as energy helps in this process.
• A dipeptide is formed as formyl metheonin is released and metheonine is joined to second position amino acid by pepetide bond.
• Ribosome moves along m-RNA in 3' direction by distance of one codon.
• Thus, one by one, t-RNA molecules carrying their amino acids gets arranged and the peptide chain elongates.

Termination

• At the 3' end of m-RNA a genetic code do not represent any position of amino acid and are known as nonsense codon or termination codon.
• Here the synthesized polypeptide chain is released from ribosomes.