According to the Endosymbiotic Theory, infoldings in the cell membrane of an ancestral prokaryotic cell gave rise to
endomembrane components, including the nucleus, endoplasmic reticulum and golgi apparatus in what would become eukaryotic
cells. The evolution of endomembrane components provided for compartmentalization in eukaryotes, leading to more efficiency
cell processes. The endomembrane system includes the endoplasmic reticulum. Which statement does NOT describe the
endoplasmic reticulum (ER)?
The ER is an extension of the nuclear envelope.
The ER serves as a transport network for the proteins produced in its
membrane.
The ER provides separate microenvironments for each of the modifications
that must take place to proteins,
D)
The ER serves a role in protein folding, lipid and steroid synthesis,
carbohidrate metabolism and calcium storage