Final answer:
The rough endoplasmic reticulum, with its surface-bound ribosomes, is the site for synthesis of enzymes intended for export in eukaryotic cells. Post-synthesis, these proteins are modified in the Golgi apparatus before being transported to their final destinations.
Step-by-step explanation:
The cellular structure most likely involved in the synthesis of enzymes for export is the endoplasmic reticulum (ER), specifically the rough ER due to the presence of ribosomes on its surface. Enzymes, which are proteins necessary for catalyzing various biological processes, are synthesized by ribosomes that are found either floating freely in the cytoplasm or attached to the rough ER. When enzymes are meant for export or for use in lysosomes, the rough ER becomes the primary site of synthesis. After synthesis, these proteins are usually sent to the Golgi apparatus for further modification and sorting, before being shipped to their final destinations.
Cells that are highly active in protein synthesis, such as those in the pancreas that produce digestive enzymes, have a large number of ribosomes. Moreover, certain enzymes are compartmentalized within specific organelles, like mitochondria, which house enzymes involved in cellular respiration; or lysosomes, which contain enzymes that break down cellular debris. This compartmentalization provides efficient and regulated chemical reactions within the cell.