Which of the following statements about the endoplasmic reticulum (ER) is CORRECT?
A) The rough ER is the site of lipid synthesis.
B) The smooth ER has ribosomes associated with it.
C) The ER is a lipid storage organelle.
D) The ER is a transport system within the cytoplasm.
E) The smooth ER is a site of ATP synthesis.
Answer: D