What are the two major functions of lipoproteins?
1. Apo B-containing particles (lower density) including chylomicrons, VDL, IDL, and LDL distribute cholesterol and triglycerides to tissues.
2. Apo A-containing particles (higher density) including HDL return cholesterol from tissues to liver, where it is reused or excreted in the bile as bile salts (reduced CHD risk)