During translation, the initiator tRNA binds with a smaller subunit of the ribosome and this assembly bind to the start codon AUG at mRNA molecule in both prokaryotes and eukaryotes and then large subunit bind to this assembly and start polypeptide chain.
So, the first codon is AUG which is start codon and code for methionine in eukaryotes and fMeth in prokaryotes at newly translated prokaryotic and eukaryotic polypeptides at the N- terminus.
Thus, the correct answer is option second - methionine.
Explanation: Photosynthesis removes CO2 from the atmosphere and replaces it with O2. Respiration takes O2 from the atmosphere and replaces it with CO2.
