Final Answer:
The correct order of locations of the protein during the chase period is C. endoplasmic reticulum → transport vesicle → Golgi → transport vesicle → secreted.
Step-by-step explanation:
In a pulse-chase experiment, the process of protein secretion involves several cellular compartments. Initially, the protein is synthesized in the endoplasmic reticulum (ER) during the pulse phase. This labeled protein then moves to the transport vesicle, which shuttles it to the Golgi apparatus. Option C correctly reflects this sequence as it goes from the endoplasmic reticulum to the transport vesicle and then to the Golgi apparatus.
After reaching the Golgi apparatus, the protein is further modified and sorted. In the chase period, transport vesicles are responsible for carrying the protein between cellular compartments. The correct sequence involves the transport vesicle shuttling the protein back to the secretory pathway, leading to eventual secretion. Option C accurately represents this process by placing the transport vesicle after the Golgi and before the final secretion step.
Options A, B, and D have incorrect sequences that do not align with the known secretory pathway. Understanding the normal flow of proteins through the secretory pathway is crucial in deducing the correct order during a pulse-chase experiment.