This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Organelles, Subject name: Biochemistry
The cellular component of protein synthesis is : 
Select and explain. 
A. Smooth endoplasmic reticulum, B. Rough endoplasmic reticulum, C. Ribosomes, D. Mitochondria
C: Ribosomes
Answer: C: Ribosomes 
Explanation: Ribosomes >> Rough endoplasmic reticulum Rough ER is that ER on which ribosomes are attached and protein synthesis occurs in ribosomes. So, best answer here is 3. Fig.: Free ribosomes present in cytoplasm (not attached to ER) Fig.: Ribosomes attached to cytosolic side of ER BUT SER is responsible for the synthesis of lipids, in detoxification and Ca sequestration & release.