a matured rna has 300 bases with single stop codon what would be the length of polypeptide synthesis from this mRna ?

Dear student,
One codon comprises three bases and one codon codes for one amino acid. Total base is 300 therefore 100 amino acids will be coded. But if stop codon is present at the end then 99 amino acid will be coded. So, the polypeptide chain length will consist of 99 amino acid.

Regards