Final answer:
Ribosomes bound up in cellular targets undergo 'ribosomal sequestration', preventing them from participating in protein synthesis, which normally proceeds through synthesis, modification, tagging, and distribution stages.
Step-by-step explanation:
When ribosomes are bound up in cellular targets, it is known as ribosomal sequestration. This term is used to describe the situation where ribosomes are prevented from participating in protein synthesis due to being bound to certain cellular components or systems that inhibit their function. During protein synthesis on the ribosome, the main stages include the initial synthesis of the protein on the ribosome, followed by modification in the endoplasmic reticulum and tagging in the Golgi apparatus, eventually leading to distribution via vesicles.