That means that the bad cholesterol tends to accumulate in the arteries, tends to form plaques, tends to be the precursor to what eventually might end up being a heart attack.
The good cholesterol actually acts in part in reversing the cholesterol transport, takes cholesterol out of the plaque in the artery and may return it to the circulation, to the liver, to be excreted. So these are the two major categories, but within each one there are different particles, different cholesterols, different lipoproteins that carry the cholesterol, and they are differentially difficult players.
Some of the LDL cholesterol that is the bad cholesterol is worse than others. And it tends to be the small particle size that are very dense. You can think of the cholesterol particles as marbles, maybe, the small dense ones, and the larger, lighter ones might be ping-pong balls. And so the small marble ones are more dangerous.
On the other side, the HDL, the good cholesterol, there are some components of that that are better than others. So cholesterol is quite a complicated subject, and we're developing more and more therapies that aim not just at the total cholesterol, but in altering the good and the bad.