Is it true that the rough endoplasmic reticulum performs the function of protein synthesis and post-translational modification?

Rough ER can be found across the cell, although it is concentrated towards the nucleus and the Golgi apparatus. 'Membrane bound' ribosomes on the rough endoplasmic reticulum are responsible for constructing numerous proteins.

RER aids in the synthesis of proteins within the cell. The RER's ability to synthesize proteins is dependent on the presence of ribosomes. As a result, RER is abundant in cells that undergo a lot of protein synthesis.

PTM (post-translational modification) is a stage in the production of proteins. Ribosomes convert mRNA into polypeptide chains, which are then translated into proteins.

These chains go through PTM, cutting, folding, and other related processes before becoming the full protein product. 

Lipids produced by the smooth endoplasmic reticulum and proteins produced by the rough endoplasmic reticulum enter the Golgi apparatus' cisternae.