The bacteria that use cholesterol to get into cells.

Although it usually only gets talked about when it starts causing problems, cholesterol is an important molecule to have in the body, as it is a component of cell membranes. The major component of cell membranes is a molecule called a phospholipid; an inorganic phosphate molecule joined onto lipid tails. Lots of these phospholipids all line up to form the cell membrane. Cholesterol is another lipid molecule, which fits in between the phosopholipids and can influence the membranes permeability and fluidity.[caption id="attachment_983" align="aligncenter" width="562" caption="Diagram of the membrane that surrounds human cells. The two layers of phospholipids can be seen (blue and while spheres with the lipid tails pointing inwards) studded with bright red proteins. The yellow blobs within the phospholipid layer are cholesterol. Image from the National Institute of Standards and Tchnology - link below"] [/caption] [More]