The main difference between chylomicrons and micelles is that chylomicrons are lipoproteins having a core of triglycerides and cholesterols and a coat made of apolipoproteins and phospholipids, whereas micelles are globules of lipid molecules that are arranged in a spherical form in an aqueous solution.
Lipids are types of insoluble molecules. They are nonpolar and hydrophobic. Some examples of lipids are waxes, steroids, and fat-soluble vitamins such as vitamin A, vitamin K, vitamin D, vitamin E, diglycerides, phospholipids, and monoglycerides. Lipids are a structural component in the cell membranes and help in signalling, storing energy, and heat insulation. As lipids are not soluble in water, they form globules in water. Micelles and chylomicrons are two such globules that take the shape of a sphere.
Key Areas Covered
1. What are Chylomicrons
– Definition, Features
2. What are Micelles
– Definition, Composition, Features
3. Similarities Between Chylomicrons and Micelles
– Outline of Common Features
4. Difference Between Chylomicrons and Micelles
– Comparison of Key Differences
Key Terms
Chylomicrons, Micelles
What are Chylomicrons
Chylomicrons are lipoproteins having a core of triglycerides and cholesterols and a coat of apolipoproteins and phospholipids. They have a high buoyancy. Large chylomicrons have a diameter of about 1000 nm, while the smallest particles have a diameter of 75 nm to 200 nm. Their primary purpose is to carry lipids through the circulation to various regions of the body. Chylomicrons also play a crucial role in the transportation of dietary triglycerides to skeletal muscles and adipose tissue. After the breakdown of triglycerides into tiny fatty acid molecules, the lipoprotein lipase enzyme facilitates their absorption by the body tissues. The remaining fat molecules are absorbed by chylomicrons, which then transport them to the liver. Thus, chylomicrons not only aid in the distribution of dietary triglycerides but also assist in preventing their accumulation in the body.
Moreover, chylomicrons are the largest of the lipoproteins. They are synthesized in the intestine. Chylomicrons are made in the endoplasmic reticulum and later processed in the Golgi complex. In the Golgi complex, the glycosylation of apoprotein takes place. These chylomicrons exit the enterocytes by exocytosis. Although they cannot pass through the capillary pores, they can easily cross into the lateral endothelial gaps.
What are Micelles
Micelles are globules of lipid molecules that are arranged in a spherical form in an aqueous solution. The formation of micelles is due to the amphiphilic nature of the fatty acids (fatty acids have a hydrophilic head and a hydrophobic tail). The size of a micelle ranges from 2 nm to 20 nm. This variation in size is due to the variation of the composition in different types of micelles.
On the outer surface, micelles have polar head groups. The hydrophobic tails are located inwards in the micelles and are away from the water; this formation occurs because they are nonpolar. Micelle contains fatty acids with a single hydrocarbon chain, facilitating the easy formation of the spherical shape due to the lesser steric hindrance. Micelles self-assemble into spherical shapes in the water. They deliver both hydrophobic and hydrophilic agents. Moreover, these kinds of structures can easily deliver macromolecules. This is because these can provide the release of macromolecules in a controlled manner.
Furthermore, the formation of micelles happens above the critical micelle concentration. Dialysis method, solid dispersion, solvent evaporation, and oil in water emulsion are the predominant methods of preparation of micelles.
Similarities Between Chylomicrons and Micelles
- Both chylomicrons and micelles are fat globules.
- Moreover, they have a hydrophilic coat and a hydrophobic core.
Difference Between Chylomicrons and Micelles
Definition
Chylomicrons are lipoproteins having a core of triglycerides and cholesterols and a coat made of apolipoproteins and phospholipids, whereas micelles are globules of lipid molecules that are arranged in a spherical form in an aqueous solution.
Major Function
Chylomicrons transport hydrophobic lipids from the small intestine to adipose, skeletal, and cardiac muscle tissue, while micelles help in the absorption of lipids and fat-soluble vitamins such as vitamins A, K, D, and E.
Composition
Moreover, chylomicrons are made up of triglycerides, cholesterol, phospholipids, and apolipoproteins, while micelles are mainly made of phospholipids.
Conclusion
In brief, chylomicrons and micelles are fat globules having a hydrophobic core and a hydrophilic coat. The main difference between chylomicrons and micelles is that chylomicrons are lipoproteins having a core of triglycerides and cholesterols and a coat of apolipoproteins and phospholipids, while micelles are globules of lipid molecules that have a spherical form in an aqueous solution.
Reference:
1. “Micelle – Overview.” Science Direct.
2. “Chylomicron – Overview.” Science Direct.
Image Courtesy:
1. “2512 Chylomicrons Contain Triglycerides Cholesterol Molecules and Other Lipids” By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
2. “Micelle scheme-en” By SuperManu – Own work (CC BY-SA 3.0) via Commons Wikimedia
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