Pancreatic cells incorporate radioactively labeled amino acids into proteins, allowing researchers to track the proteins' intracellular locations. We are particularly interested in tracking an enzyme that pancreatic cells ultimately secrete. Therefore, the most probable pathway for this protein within the cell is: A. ER -> Golgi -> Nucleus B. Golgi -> ER -> Lysosome C. Nucleus -> ER -> Golgi D. ER -> Golgi -> Vesicles that fuse with the plasma membrane E. ER -> Lysosomes -> Vesicles that fuse with the plasma membrane The correct answer is D: ER -> Golgi -> Vesicles that fuse with the plasma membrane.
Biology · High School · Thu Feb 04 2021
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The correct path for a secretory protein, such as an enzyme that pancreatic cells ultimately secrete, is D: ER -> Golgi -> Vesicles that fuse with the plasma membrane. This is because, in the cell, proteins meant for secretion are synthesized in the endoplasmic reticulum (ER), where they enter the secretory pathway. After synthesis, they are transported to the Golgi apparatus for further processing, sorting, and packaging. Finally, they are directed to vesicles, which deliver them to the cell surface where they fuse with the plasma membrane and release their contents outside of the cell.