Lipid 1

• What is the process of lipid absorption in the intestinal lumen called?

  Esterification of lipid in enterocyte
• What are chylomicrons?

  One type of lipoproteins
• How are water-insoluble lipids transported in blood plasma?

  By forming water-miscible lipoproteins
• What must be transported between tissues and organs?

  Fat absorbed from diet and synthesized lipids
• What components make up water-miscible lipoproteins?

  Nonpolar lipids, amphipathic lipids, and proteins
• What are lipoproteins?

  • Spherical macromolecular complexes
  • Composed of lipids and apolipoproteins
  • Travel in blood or lymphatic capillaries
• What is the membrane structure of lipoproteins?

  • Monolayer phospholipid
  • Apolipoproteins
  • Unesterified/free cholesterol
• Name one type of apolipoprotein.

  Apo A
• What is one role of apolipoproteins?

  Structure of lipoprotein
• Which apolipoproteins are ligands for lipoprotein receptors?

  Apo E and B-100 for LDL receptor
• What is the function of Apo A-I?

  Co-factor for Lecithin-Cholesterol Acyl Transferase
• What does Apo E do?

  Activates Hepatic lipase
• What are the five types of lipoproteins?

  1. Chylomicrons
  2. Very Low Density Lipoproteins (VLDLs)
  3. Intermediate Density Lipoproteins (IDLs)
  4. Low Density Lipoproteins (LDLs)
  5. High Density Lipoproteins (HDLs)
• How do lipoproteins differ?

  In composition, size, density, and origin
• Where are chylomicrons synthesized?

  In the ER of intestinal cells
• What do chylomicrons carry?

  TAGs and esterified cholesterol
• What is the main function of VLDLs?

  Transport TAGs synthesized in liver
• How are LDLs formed?

  From IDL in the blood
• What is the primary role of LDLs?

  Transport cholesterol to peripheral tissue
• How does high intracellular cholesterol affect LDL receptors?

  It suppresses their synthesis
• What is the main function of HDLs?

  Transport unused cholesterol back to liver
• What enzyme is involved in HDL metabolism?

  Lecithin-Cholesterol Acyl Transferase (LCAT)
• What happens to oxidized LDL?

  It becomes sticky and leads to atherosclerosis
• What is atherosclerosis?

  • Deposit of oxidized LDL in arteries
  • Recruitment of macrophages to remove LDL
  • Formation of foam cells from overloaded macrophages
  • Chronic inflammation leads to fibrous proliferation
  • Narrowing of vessel wall due to fibrous plaque
• What effect do saturated lipids have on LDL?

  They raise LDL levels
• What effect do trans lipids have on LDL and HDL?

  Raise LDL and lower HDL
• What effect do unsaturated lipids have on LDL?

  They lower LDL levels
• What is the effect of omega-3 polyunsaturated fats on blood cholesterol?

  They lower blood cholesterol