The turnover rates for enzymes also varies greatly from protein to protein and cell to cell. Membrane bound organelles besides the nucleus. When those attached ribosomes make a protein, they deposit it into the lumen of the rough e.r. The protein may be processed in the lumen area. It may also be transported in the lumen space to other parts of the cell.
Endoplasmic reticulum has the ability to assemble the lipids needed in making membranes.
Therefore, e.r. is thought to make its own membrane. E.r. pinches off to form microbodies . Rough e.r. is thought to be continuous with the nuclear membrane. Smooth e.r. forms the Golgi apparatus. A vesicle with a single membrane, about 0.7 m in diameter.