Final answer:
The signal sequence of amino acids does not remain on the mature, fully translated protein; it is cleaved upon the protein reaching its intended cellular destination.
Step-by-step explanation:
The signal sequence of amino acids plays a crucial role in determining the destination of a newly synthesized protein within a cell. It serves as a sort of "train ticket," ushering the protein to specific compartments such as mitochondria or chloroplasts. However, once a protein reaches its intended cellular compartment, this signal sequence is typically removed. This process involves various steps including the recognition of the signal sequence by cellular factors, its transportation to the correct compartment, and the eventual cleavage of the sequence.
Notably, experiments related to the Signal Hypothesis indicated that the translated protein in its mature form is indeed shorter than its in vitro counterpart, providing further evidence that the signal sequence does not remain on the mature fully translated protein. These sequences at the amino end or the carboxyl end of the protein can be thought of as the protein's "train ticket" to its ultimate destination. Once the protein reaches its cellular destination, the signal sequence is usually clipped off.