In what ways are a promoter and a start codon similar in what ways are they different Drag the terms on the left to the appropriate blanks on the right to complete the sentences. A promoter and a start codon are similar in that both are sequences ofthat are required to start important processes, and both determine the sites where the process will begin. the key differences are that the promoter is needed to start and the start codon is needed to start. Also, the promoter is aonly, and the start codon is a sequence found within a:. 1. nucleic acids 2. proteins 3. transcription 4. translation 5. mRNA 6. tRNA 7. DNA sequence 8. RNA sequence