Why are stop and start codon signals necessary for protein synthesis?

Stop and start codon signals are necessary for protein synthesis because they help to indicate where a protein should begin and end. The start codon signals the beginning of protein synthesis, while the stop codon signals the end, ensuring that the correct sequence of amino acids is translated from the mRNA into a functional protein. Without these signals, the process of protein synthesis would not be properly regulated, leading to errors in protein production.