Translation is the decoding of m-RNA to form amino acid chain with the help of ribosome in the cytosol of the cell.
Molecules Involved In Translation:
1. Amino acids: These are the structural unit of proteins which are joined together to form a protein chain.
2. m-RNA: The m-RNA or messenger RNA has codons, each codon codes for one amino acid.
3. t-RNA: The t-RNA or transfer RNA binds with amino acid carrier and carry the amino acid sequence.
4. Ribosome: These are required for the catalysis of the process.
Steps Involved In Translation:
1. At the 5’ end of the m-RNA the smaller 40S subunit of the ribosome with methionyl-tRNA scans the m-RNA to find the start codon (5’AUG).
2.This codon (AUG) is specific to methionine.
3.Now, the larger 60S subunit of the ribosome binds to the m-RNA.This 60S ribosomal subunit has two t-RNA binding sites.
Site P: This site can hold the peptide chain.
Site A: This site can hold the t-RNA.
1. Now, as the Met-tRNA binds to the P site of the 60S subunit of the RNA. Another aminoacyl- tRNA which has an anticodon complementary to the next codon occupies the site A within the 60S subunit of ribosome.
2. The enzyme peptidyl transferase forms a peptide bond between Methionyl-tRNA and Aminoacyl-tRNA.
3. This makes the t-RNA molecule at the P site to become uncharged and it leaves the ribosome.
4. The ribosome moves along the m-RNA molecule to the next codon which opens the Site A for next aminoacyl-tRNA.
5. The polypeptide chain is built in the direction of N to C terminal.
1. Now, as the A site is vacant the stop codon enters the site.
2. None of the t-RNA molecule binds to this codon.
3.The peptide bond of Methionyl-tRNA and Aminoacyl-tRNA become hydrolysed releasing the polypeptide into the cytoplasm.
4. The ribosomal subunit now disassociates.
Rate this question :
What is aminoacylBiology - Board Papers