This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Rough endoplasmic reticulum is the site of synthesis for 
Select and explain. 
A. Protein, B. Cholesterol, C. Carbohydrate, D. Fat
A: Protein
Answer: A: Protein 
Explanation: Rough endoplasmic reticulum is concerned with Protein synthesis*
Initial folding of the polypeptide chains with the formation of disulfide bonds Smooth endoplasmic reticulum is concerned with Steroid synthesis
* Detoxication processes As sarcoplasmic reticulum plays important role in skeletal and cardiac muscle contraction *