Question

Two lipoproteins have the following characteristics:

	Diameter (A) %	Triacylglycerol %	Protein
Lipoprotein A	200	10	20
Lipoprotein B	100	5	55

Which lipoprotein has a higher density?

Short answer

Lipoprotein B has a larger protein-to-triacylglycerol ratio, 11. Therefore, it is denser than lipoprotein A.

Step-by-step solution

Explanation of Concept 

A lipoprotein is a metabolic assembly that is primarily responsible for transporting hydrophobic lipid molecules in extracellular fluids like blood plasma.

Characteristics of Lipoproteins 

Lipoproteins are nonpolar lipid-protein complexes surrounded by an amphipathic lipid and apolipoprotein coat that transports lipids in the bloodstream.

Therefore, the lipid molecules have a lower density than proteins, higher density lipoproteins have a higher protein-to-triacylglycerol ratio.

Finding the Ratio of Lipoproteins

Lipoproteins A and B have a protein/triacylglycerol ratio of:

lipoprotein $A=\frac{20}{10}=2$

lipoprotein $B=\frac{55}{5}=11$

Hence, the lipoprotein B has a higher protein/triacylglycerol ratio, so it is denser.