HOW IS RNA TRANSLATED ?
Translation occurs in three steps : 1 . Initiation 2 . Elongation 3 . Termination All three phases of translation involve ribosomes , which direct the translation process .
The corresponding tRNA then binds to this codon . For a short time , there are two tRNA molecules on the mRNA strand and the amino acids carried by these tRNA molecules are then bound together .
Each individual amino acid has an amino group ( NH2 ) and a carboxyl group ( COOH ). Polypeptides are formed when the amino group of one amino acid forms a bond with the carboxyl group of another amino acid .
STEP 1 The ribosome attaches to the mRNA strand at the start codon . The start codon is almost always AUG , which corresponds to the amino acid methionine . Next , the specific tRNA molecule with the anticodon UAC ( and carrying methionine ) recognizes the start codon and binds to it .
STEP 2 Elongation begins when the ribosome shifts to the next codon on the mRNA template , in a 5 ’ to 3 ’ direction .
Polysomes
After this binding has occurred , the ribosome shifts again , and the first tRNA , which is no longer connected to its corresponding amino acid , is released . This process is repeated along the entire length of the mRNA , thereby creating a progressively elongated polypeptide chain .