Cholesterol

• What type of molecule is cholesterol?

  Cholesterol is a type of lipid.
• What are the main functions of cholesterol in the body?


  Cholesterol is required for cell membrane functioning, sex hormone structure, and bile synthesis.
• Why is cholesterol not soluble in water?


  Like all lipids, cholesterol is not soluble in water.
• How is cholesterol transported in the bloodstream?


  Insoluble cholesterol is combined with proteins to form soluble lipoproteins.
• What are lipoproteins composed of?


  Lipoproteins are composed of lipid and protein.
• What are the two types of lipoproteins?

  The two types of lipoproteins are high density lipoproteins (HDLs) and low density lipoproteins (LDLs).
• What do high density lipoproteins (HDLs) contain?


  HDLs contain unsaturated fat, cholesterol, and protein.
• What is the role of HDLs in the body?


  HDLs transport cholesterol from body tissues to the liver to be recycled or excreted.
• How do HDLs affect blood cholesterol levels?


  HDLs reduce blood cholesterol levels when it is too high.
• What role do HDLs play in atherosclerosis?


  HDLs contribute to the removal of cholesterol from fatty plaques that form during atherosclerosis.
• What is the function of lipoprotein lipase?


  Lipoprotein lipase is involved in the hydrolysis of triglycerides.
• What is the result of hydrolysis of triglycerides?


  Hydrolysis results in bonds between glycerol and a fatty acid being broken and water being formed.
• What is a triglyceride made from?


  A triglyceride is made from one glycerol and three fatty acids.
• What type of bond is found in a triglyceride?


  A type of bond found in a triglyceride is an ester bond.
• What do low density lipoproteins (LDLs) contain?


  LDLs contain saturated fat, cholesterol, and protein.
• What is the role of LDLs in the body?


  LDLs remove cholesterol from the liver to the bloodstream where it remains until required by cells.
• How do LDLs affect blood cholesterol levels?


  LDLs increase blood cholesterol levels when it's too low.
• How do LDLs interact with cells?


  LDLs bind to receptors on the cell surface membranes, enabling them to be taken up by cells that need them.
• What can high levels of LDLs lead to?


  High levels of LDLs can lead to blockage of membrane receptors, causing blood cholesterol to rise.
• What is the structural difference between HDL and LDL?


  HDLs contain unsaturated fats, while LDLs contain saturated fats.
• How does a diet very high in saturated fats affect cholesterol levels in the blood?


  A diet high in saturated fats can increase levels of LDLs in the blood.
• Are LDLs considered bad? Explain your answer.


  Yes, because high levels of LDLs can lead to increased blood cholesterol and cardiovascular disease.
• What are the main roles of lipids in the body?


  • Source of energy
  • Structural components of cell membranes
  • Signaling molecules
• Describe the structure of an HDL.


  • Contains unsaturated fat
  • Contains cholesterol
  • Contains protein
• Describe the structure of an LDL.


  • Contains saturated fat
  • Contains cholesterol
  • Contains protein
• What are the differences between HDL and LDL?


  • HDLs contain unsaturated fats; LDLs contain saturated fats
  • HDLs transport cholesterol to the liver; LDLs transport cholesterol to cells
  • HDLs reduce blood cholesterol; LDLs increase blood cholesterol