what is membrane biogenesis?

In simple words, membrane biogenesis is the formation or synthesis of biological membranes.

This involves lipid synthesis in the smooth endoplasmic reticulum and protein biosynthesis in the rough endoplasmic reticulum. These two major components are arrayed giving rise to the membrane. With respect to the formation of plasma membrane, Golgi complex has to add carbohydrate moiety to the protein already formed in the RER.