Final answer:
Proteins synthesized on membrane-bound ribosomes are translocated into the RER where they undergo modifications. They are then packed into transport vesicles, moved to the Golgi for further processing, and finally, incorporated into membranes or secreted.
Step-by-step explanation:
The process in which proteins are translocated into the endoplasmic reticulum (ER) during their synthesis on membrane-bound ribosomes is a fundamental aspect of cell biology. Ribosomes synthesize proteins, and when they are attached to the rough endoplasmic reticulum (RER), these proteins are translocated into the RER's lumen. Here, proteins undergo important structural modifications, such as folding or acquiring side chains, which are crucial for their function. After synthesis, these proteins are transported within the cell by transport vesicles that bud from the ER and fuse with the Golgi apparatus. In the Golgi, proteins receive further modifications and sorting before reaching their final destinations such as incorporation into cellular membranes or secretion out of the cell.