Questions: [SELECT ALL THAT APPLY] Which of the following is/are TRUE regarding LPL and CMs? LPL releases free fatty acids and glycerol from the adipose tissue. LPL is located in the cytoplasm of muscle cells and adipocytes. LPL is activated by ApoCII of chylomicrons. CM remnants are uptaken by the liver. CM remnants contain high level of triglycerides. CM remnants use ApoB-48 as ligand for uptake.

The answer is the third one (C), the fourth one (D), and the sixth one (F):

1. LPL releases free fatty acids and glycerol from the adipose tissue.

   • Incorrect. LPL (lipoprotein lipase) primarily hydrolyzes triglycerides in chylomicrons and very-low-density lipoproteins (VLDL) into free fatty acids and glycerol, but it does this in the capillaries of adipose tissue and muscle, not by releasing them from adipose tissue directly.

2. LPL is located in the cytoplasm of muscle cells and adipocytes.

   • Incorrect. LPL is located on the endothelial surface of capillaries in adipose tissue, muscle, and heart, not in the cytoplasm of these cells.

3. LPL is activated by ApoCII of chylomicrons.

   • Correct. ApoCII is a cofactor for LPL and activates it, allowing the enzyme to hydrolyze triglycerides in chylomicrons.

4. CM remnants are uptaken by the liver.

   • Correct. Chylomicron remnants are taken up by the liver through receptor-mediated endocytosis.

5. CM remnants contain high level of triglycerides.

   • Incorrect. Chylomicron remnants have already delivered most of their triglyceride content to tissues and therefore contain lower levels of triglycerides compared to intact chylomicrons.

6. CM remnants use ApoB-48 as ligand for uptake.

   • Correct. ApoB-48 is one of the apolipoproteins on chylomicron remnants that facilitates their uptake by the liver.