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
Metabolically the most active of the plasma lipids is 
Select and explain. 
A. Phospholipids, B. Cholesterol, C. Triacylglycerol, D. Free fatty acids
D: Free fatty acids
Answer: D: Free fatty acids 
Explanation: Free fatty acids 

Plasma lipids consist of triacylglycerols (16%), phospholipids (30%), cholesterol (14%) and cholesteryl esters (36%), and a much smaller fraction of unesterified long chain fatty acids (4%). This latter fraction, the free fatty acids (FAA), is metabolically the most active of the plasma lipids.