The correct answer is: a) It attaches to proteins that are marked for destruction in the cell.
Ubiquitin is a regulatory protein of eukaryotic cell with the various of function. The mechanism of its action involves the addition of ubiquitin to a substrate protein (ubiquitination). Ubiquitin regulatory roles are:
• marking thee proteins for degradation via the proteasome,
• alter the cellular location of proteins,
• promoting or preventing protein interactions.
