Question

what is the difference between RER and SER

Answer 1

full form of RER is Rough Endoplasmic Reticulum this contains ribosomes in their surface so,appears rough whereas Full Form of SER is Smooth Endoplasmic Reticulum
which doesn't contain any ribosomes in their surface so,appear smooth
Ribosomes help in synthesis of some enzymes required by RER which is not required by SER.

Answer 2

RER
1) Rough endoplasmic reticulum has ribosomes attached to it giving the rough appearance.
2) Involved in protein synthesis.

SER
1) Smooth endoplasmic reticulum devoid of ribosomes.
2) Concerned with lipid synthesis.