Question

The majority of secreted proteins are:

A) synthesized in the smooth ER, then modified in the Golgi, and released by exocytosis into the extracellular space
B) synthesized in the rough ER, then modified in the Golgi, and remain in the cytosol
C) synthesized in the rough ER, then modified in the Golgi, and released by exocytosis into the extracellular space.
D) none of the above

Answer 1

The correct answer is that secreted proteins are synthesized in the rough endoplasmic reticulum (rough ER), modified in the Golgi apparatus, and then released into the extracellular space via exocytosis.

Step-by-step explanation:

The majority of secreted proteins are synthesized in the rough ER, then modified in the Golgi apparatus, and released by exocytosis into the extracellular space. The rough ER is responsible for the synthesis and initial modification of proteins, where they may undergo processes such as glycosylation.

Subsequently, these proteins are packaged into vesicles that travel to the Golgi apparatus, undergoing further modifications and sorting. Finally, the mature proteins are packed into secretory vesicles that bud from the trans face of the Golgi, which then fuse with the plasma membrane to release their contents outside the cell.