What Can Be Used to Distinguish RER from SER

Question

What can be used to distinguish RER from SER?
A)the location of the ER
B)the proximity of the ER to the nucleus
C)the protein make-up of the ER
D)the shape of its component lipids

Accepted Answer

RER and SER have different protein make-up. RER is studded with ribosomes which synthesize proteins, while SER lacks ribosomes and is involved in lipid metabolism. Therefore, the presence or absence of ribosomes and the protein make-up of the ER can be used to distinguish RER from SER.