Lip protein

• What are lipids commonly referred to as?

  Fats
• What dual role do lipids play in the body?

  They serve as a rich source of energy and play a structural role in cell membranes.
• What are the principal lipids transported by lipoproteins?

  Triglycerides, phospholipids, cholesterol, and cholesteryl esters.
• What is the structure of fatty acids?

  Linear chains of C-H bonds that terminate with a carboxyl group (-COOH).
• In what form do most plasma fatty acids exist?

  As constituents of triglycerides or phospholipids.
• How are fatty acids attached to glycerol in triglycerides and phospholipids?

  By an ester bond that forms between the carboxyl group on the fatty acid and the hydroxyl group on glycerol.
• How are fatty acids classified based on their length?

  Short-chain (4–6 carbon atoms), medium-chain (8–12 carbon atoms), or long-chain (more than 12 carbon atoms).
• What type of fatty acids are most commonly found in our diet?

  Long-chain fatty acids with an even number of carbon atoms.
• What do triglycerides contain?

  Three fatty acid molecules attached to one molecule of glycerol.
• How do saturated and unsaturated fatty acids affect the state of triglycerides at room temperature?

  Saturated fatty acids tend to be solid, while cis unsaturated fatty acids typically form oils.
• What are the sources of triglycerides in terms of their saturation?

  Plant sources are rich in polyunsaturated fatty acids and are oils, while animal sources contain mostly saturated fatty acids and are usually solid.
• How do phospholipids differ from triglycerides in structure?

  Phospholipids have two esterified fatty acids and a phospholipid head group, while triglycerides have three fatty acids.
• What are some examples of phospholipid head groups?

  Choline, inositol, serine, and ethanolamine.
• Why are phospholipids considered amphipathic molecules?

  Because they contain both hydrophobic fatty acid chains and a hydrophilic head group.
• How is cholesterol structured?

  Cholesterol is an unsaturated steroid alcohol containing four rings and a single C-H side chain tail.
• What is the role of the hydroxyl group in cholesterol?

  It is the only hydrophilic part of cholesterol and allows it to interact with water.
• How is cholesterol oriented in lipid layers?

  Cholesterol is oriented so that its four rings and side chain tail are buried in the membrane, while the polar hydroxyl group faces outward.
• What is cholesteryl ester?

  It is an esterified form of cholesterol where the hydroxyl group is conjugated by an ester bond to a fatty acid.
• What is the function of lipoproteins in the body?

  Lipoproteins transport dietary triglycerides and cholesterol throughout the circulatory system.
• What are chylomicrons compared to in the text?

  They are compared to large oil tankers transporting dietary triglycerides.
• What is the primary role of chylomicrons?

  The delivery of dietary lipids to hepatic and peripheral cells.
• What is the composition of VLDL?

  VLDL contains apo B-100, apo E, and apo Cs, and is rich in triglycerides.
• How does excess dietary intake affect VLDL production?

  It enhances hepatic synthesis of triglycerides, which increases VLDL production.
• How do LDL particles form?

  LDL particles form as a consequence of the lipolysis of VLDL.
• What happens to macrophages that take up too much lipid?

  They become filled with intracellular lipid drops and turn into foam cells.
• What is HDL known for?

  HDL is the smallest and most dense lipoprotein particle.
• What is the main mechanism proposed for HDL's antiatherogenic property?

  The ability of HDL to remove cholesterol from cells, known as reverse cholesterol transport.
• What are lipoprotein(a) particles similar to?

  LDL-like particles.
• How does the concentration of lipoprotein(a) relate to its size?

  The concentration of lipoprotein(a) is inversely related to the size of the isoform.
• What is the significance of elevated levels of lipoprotein(a)?

  They are thought to confer increased risk for premature coronary heart disease and stroke.
• What are the main components of lipoprotein structure?

  • Outer coat: Apoproteins, phospholipids, cholesterol
  • Inner core: Triglycerides, cholesteryl esters
• What are the types of lipoproteins and their functions?

  1. Chylomicrons: Transport dietary triglycerides
  2. VLDL: Carry endogenous triglycerides from the liver
  3. LDL: Deliver cholesterol to cells
  4. HDL: Remove excess cholesterol from cells
• What are the physiological roles of lipids and lipoproteins?

  • Energy metabolism
  • Structural components of cell membranes
  • Transport of lipids in the bloodstream
  • Association with coronary heart disease (CHD)
• What are the steps in the metabolism of chylomicrons?

  1. Release nascent chylomicrons from intestines
  2. Receive apolipoproteins E and C from HDL
  3. Hydrolyze triglycerides into glycerol and fatty acids
• How do the sizes and densities of lipoproteins correlate with their lipid content?

  • Larger lipoproteins have larger core regions and more triglycerides
  • Larger lipoproteins are lighter in density
  • Smaller lipoproteins have more protein relative to lipid
• What are the subclasses of HDL based on density differences?

  • HDL2: Larger and richer in lipid
  • HDL3: Smaller and less lipid-rich
• What is the role of apolipoproteins in lipoproteins?

  • Maintain structural integrity
  • Serve as ligands for cell receptors
  • Act as activators and inhibitors of enzymes
• What are the implications of high blood lipid levels in affluent countries?

  • Clear association with the development of atherosclerosis
  • Increased risk of coronary heart disease (CHD)
• What is the significance of foam cells in atherosclerosis?

  • Foam cells are filled with lipid drops
  • They are predominant in fatty streaks, early precursors of atherosclerotic plaques
• What factors influence VLDL production?

  • Excess dietary intake of carbohydrates, saturated, and trans fatty acids
  • Free fatty acids released by adipocytes stimulate VLDL secretion