Biochemistry · MU Sofia

32. TRANSPORT OF LIPIDS IN ORGANISM. TYPES - COMPOSITION,

Covers how lipids are carried in the blood as lipoprotein complexes, starting with their composition of lipids and apolipoproteins. It then classifies chylomicrons, VLDL, IDL, LDL and HDL by density and size, with their origin and roles such as reverse cholesterol transport. The note also touches on apolipoprotein functions, receptors, and familial hypercholesterolaemia with its genetic basis and treatment, and ends with four multiple-choice questions.

Inside: 19 sections · 8 labelled pictures · 10 flashcards · 7 min

Topic 32 of 70 in the MU Sofia syllabus for Biochemistry (Medicine, Year 2). The free AceMed note covers it in 12 sections, about 974 words (7 min of reading), with 10 flashcards.

In this note

  1. Introduction
  2. BIOCHEM POINT 32: TRANSPORT OF LIPIDS IN ORGANISM. TYPES - COMPOSITION, ORIGIN AND FUNCTIONS OF LIPOPROTEIN COMPLEXES...
  3. Transport of Lipids in Organisms
  4. Classification of Lipoproteins
  5. Types of Lipoprotein Complexes
  6. Role of Proteins in Lipoproteins
  7. Formation, Degradation, and Conversion of Lipoproteins
  8. Receptors for Lipoproteins
  9. Familial Hypercholesterolemia; Brief Introduction
  10. Familial Hypercholesterolemia; In Depth
  11. MCQs ☺
  12. Answers

BIOCHEM POINT 32: TRANSPORT OF LIPIDS IN ORGANISM. TYPES - COMPOSITION, ORIGIN AND FUNCTIONS OF LIPOPROTEIN COMPLEXES...

FATMA WARSAME

Transport of Lipids in Organisms

Introduction to Lipid Transport

  • Lipids are essential molecules for various biological processes including energy storage, cell membrane structure, and signalling.
  • Due to their hydrophobic nature, lipids require specialized transport mechanisms in aqueous environments like blood plasma.

Transport of Lipids in Organisms

Types of Lipoprotein Complexes: Composition

  • Lipoprotein complexes consist of lipids (mainly triglycerides and cholesterol esters) and proteins.
  • Proteins associated with lipoproteins are known as apolipoproteins and play crucial roles in their structure and function.

Classification of Lipoproteins

Lipoproteins are classified based on their density, size, and composition. The major classes of lipoproteins include:

  1. 1. Chylomicrons:
  • Largest and least dense lipoproteins.
  • Formed in the intestine to transport dietary lipids (triglycerides) to peripheral tissues.
  • Composed mainly of triglycerides, phospholipids, cholesterol, and apolipoproteins.
  1. 2. Very Low-Density Lipoproteins (VLDL):
  • Produced by the liver to transport endogenous triglycerides to peripheral tissues.
  • Larger and less dense than LDL.
  • Mainly composed of triglycerides, phospholipids, cholesterol, and apolipoproteins.
  1. 3. Intermediate-Density Lipoproteins (IDL):
  • Intermediate between VLDL and LDL in size and density.
  • Formed from the metabolism of VLDL.
  • Contains triglycerides, cholesterol, and apolipoproteins.
  1. 4. Low-Density Lipoproteins (LDL):
  • Main carriers of cholesterol in the bloodstream.
  • Formed from the metabolism of VLDL and IDL.
  • Smaller and denser than VLDL and IDL.
  • Predominantly composed of cholesterol esters, phospholipids, and apolipoproteins, with minimal triglycerides.
  1. 5. High-Density Lipoproteins (HDL):
  • Smallest and densest lipoproteins.
  • Synthesized in the liver and intestine.
  • Involved in reverse cholesterol transport, transporting cholesterol from peripheral tissues back to the liver for excretion.
  • Composed primarily of phospholipids, free cholesterol, and apolipoproteins.

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