Before anyone asks, yes, I did take Olivia Netwon Johns' "Let's get Physical" and give it a scientific application (it was one of my ways of remembering lipid arrangements.
So we know that lipids are amphiphilic (meaning that they have both a hydrophobic head, and hydrophilic tail, or on occasion the other way around). Either way, due to the hydrophobic effect (which as we were told last week, should more aptly be called the hydrophilic effect, as water loves water more) the lipids aggregate themselves into different types of arrangements so as to decrease the overall energy of the system. These arrangements include:
* micelles - like a soccer ball, where each of the hexagons making up the ball have a tail attached, which exists inside the ball (except replace the hexagon with the hydrophilic head)
* bilayer - the classic arrangement we've all been taught for cell membranes, where there are two layers of lipids which come together to create a semipermeable layer.
* vesicle - like a fusion of a micelle and a bilayer. There is the micelles structure, with then what we can consider a reverse micelle within the micelle, interacting with the micelle in the same way that the two layers of the bilayer interact.
Associated with the micelles is a term known as the critical micelle concentration. This term, the CMC, refers to the point where the concentration of lipids is high enough to spontaneously form structures such as a micelle.