Question

Ls4203_endsem_2017

The question is from Advanced Biochemistry and cellular metabolism.

7. What are lipoproteins explain with example? Explain lipid transport with the help of lipoproteins. How lipoprotein transport related to heart disease ? (2+2+2=6 marks)

Answer 1

7. Ans-
                 Lipoproteins are special particles that consist of droplets of fats surrounded and have a single layer of phospholipid molecules and play an important role to transport lipid molecules in blood or extracellular fluid. Examples- Plasma lipoprotein particles.

                 Lipoproteins transport lipid by receptor-mediated endocytosis from blood or extracellular fluid. LDL involves delivering cholesterol into cells where cells take up cholesterol through receptor-mediated endocytosis. Specific LDL receptor binds LDL that internalized in an endocytic vesicle.HDL plays an important role in reverse cholesterol transport where excess cholesterol is eliminated from the body through the liver that releases cholesterol in bile. Thus, the liver removes LDL and other lipoproteins by receptor-mediated endocytosis from blood or extracellular fluid.

                Lipoproteins cause heart disease. The main function of lipoproteins is to carry the cholesterol through the blood. Some of them cause cholesterol to penetrate the artery wall, resulting the artery to clog. Lipoproteins like HDLs and LDLs both transport the cholesterol through the body. VLDLs become LDL by lose some lipids and pick up cholesterol in the bloodstream where LDLs deliver the cholesterol into the cells. During this process, VLDLs and LDLs can squeeze through blood vessel walls where the cholesterol gets stuck to the blood vessel walls to form plaque. As enough cholesterol gets stuck on the vessel walls that may cause clogged and blood cannot flow through, resulting in a heart attack or stroke.