Secretory proteins are synthesized in: (A) Cytoplasm, (B) Endoplasmic Reticulum, (C) First in cytoplasm and then in Endoplasmic Reticulum, (D) First in Endoplasmic Reticulum and then in cytoplasm
Answer is B. ER is a network of interconnecting membranes enclosing channels or cisternae, that are continuous from outer nuclear envelope to outer plasma membrane. This will be very prominent in cells actively synthesizing proteins,e.g.immunoglobulin secreting plasma cells. The proteins , glycoproteins and lipoproteins are synthesised in the ER. REFERENCE:DM.VASUDEVAN.Textbook. SEVENTH EDITION ; PAGE NO 12