Question

Are micelles alive?

Answer 1

Micelles are lipid molecules that arrange themselves in a spherical form in aqueous solutions. The formation of a micelle is a response to the amphipathic nature of fatty acids, meaning that they contain both hydrophilic regions (polar head groups) as well as hydrophobic regions (the long hydrophobic chain). Micelles contain polar head groups that usually form the outside as the surface of micelles. They face to the water because they are polar. The hydrophobic tails are inside and away from the water since they are nonpolar. Fatty acids from micelles usually have a single hydrocarbon chain as opposed to two hydrocarbon tails. This allows them to conform into a spherical shape for lesser steric hindrance within a fatty acid. Fatty acids from glycolipids and phospholipids, on the other hand, have two hydrophobic chains that are too bulky to fit into the a spherical shape as micelles do. Thus, they preferred to form glycolipids and phospholipids as "lipid bilayers".

Micelles form spontaneously in water, as stated above this spontaneous arrangement is due to the amphipatic nature of the molecule. The driving force for this arrangement is the hydrophobic interactions the molecules experience. When the hydrophobic tails are not sequestered from water this results in in the water forming an organized cage around the hydrophobic tail and this entropy is unfavorable. However, when the lipids form micelles the hydrophobic tails interact with each other, and this interaction releases water from the hydrophobic tail and this increases the disorder of the system, and this increase in entropy is favorable.

They are part of soap, hence they are not alive.