The endoplasmic reticulum
A) is part of a continuous membrane system throughout the cell
B) occurs in two forms, rough and smooth
C) can have ribosomes bound to it
D) all of the above

Question

Quizplus · Accepted Answer

The endoplasmic reticulum (ER) is indeed a continuous membrane system that permeates the cell, exists in two forms (rough ER, with ribosomes, and smooth ER, without ribosomes), and can have ribosomes bound to it, particularly in the case of the rough ER, which is involved in protein synthesis.

The Endoplasmic Reticulum