What is the significance of the last triplet (taa) in a genetic sequence?

• A. It acts as a promoter region for transcription.
• B. It codes for the amino acid lysine.
• C. It initiates the process of DNA replication.
• D. It serves as a stop codon, signaling the end of translation.

Answer: (D)

Verified step by step guidance

1. Understand that a genetic sequence is read in sets of three nucleotides called codons, each of which corresponds to a specific amino acid or a signal during protein synthesis.
2. Recognize that the triplet 'taa' is one of the three standard stop codons in the genetic code, along with 'tag' and 'tga'.
3. Know that stop codons do not code for any amino acid; instead, they signal the termination of translation, the process where the ribosome stops adding amino acids to the growing polypeptide chain.
4. Differentiate stop codons from other important regions such as promoters (which initiate transcription) and start codons (which initiate translation).
5. Conclude that the significance of the last triplet 'taa' is that it serves as a stop codon, signaling the end of translation and thus the completion of the protein synthesis.