Where does most new membrane synthesis take place in a eukaryotic cell?

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The majority of new membrane synthesis in eukaryotic cells takes place in the endoplasmic reticulum (ER). The ER is a network of membrane-bound sacs and tubules that extends throughout the cytoplasm and has two distinct regions: the rough ER (RER) and the smooth ER (SER). The RER is studded with ribosomes, which synthesize proteins that are translocated into the lumen of the RER as they are being synthesized. The proteins fold and often undergo post-translational modifications in the lumen of the RER before being transported to their final destination. As the proteins are being synthesized, the ribosomes attached to the RER are also synthesizing new membrane lipids which are integrated into the growing membrane of the RER. As the membrane of the RER grows, it buds off into small vesicles which transport molecules to other organelles or to the cell surface. The SER, on the other hand, is involved in a variety of lipid metabolism processes, including synthesis of new lipids which can be incorporated into cell membranes as required.

Where Does Most New Membrane Synthesis Take Place in a Eukaryotic