Cholesterol, from the Ancient Greek chole and stereos (solid) followed by the chemical suffix -ol for an alcohol, is an organic molecule. It is a sterol, a lipid molecule and is biosynthesized by all animal cells because it is an essential structural component of all animal (not plant or bacterial) cell membranes that is required to maintain both membrane structural integrity and fluidity. Cholesterol enables animal cells to not need a cell wall (like plants and bacteria) to protect membrane integrity and cell viability, thus are able to change shape and move about (unlike bacteria and plant cells which are restricted by their cell walls).
In addition to its importance within cells, cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acids, and vitamin D. Cholesterol is the principal sterol synthesized by animals. All kinds of cells in animals can produce it. In vertebrates the hepatic cells typically produce greater amounts than other cells. It is almost completely absent among prokaryotes (bacteria and archaea), although there are some exceptions such as Mycoplasma, which require cholesterol for growth.
The following are 10 things you might not know about cholesterol:
Heart risk and more
by Sarah KleinLike most people, you probably think of cholesterol—if you think of it at all—and picture fatty foods and heart trouble. Yes, elevated blood cholesterol is bad news, and 34 million Americans have levels that can increase their risk of all sorts of health problems, including a heart attack.
But if you think you’ve heard everything you need to know about this waxy fat, there may be a few surprises in store. For one, cholesterol can be so high that it shows up in fatty deposits in the skin. On the other end of the spectrum, cholesterol can even be too low.
High cholesterol inevitable for some
If you have sky-high cholesterol, it may be partly genetic. But for some families, it’s inevitable that LDL, or bad cholesterol, will be in the unhealthy zone. The disease, known as familial hypercholesterolemia, affects about 1 in 500 people and can cause total cholesterol levels from 300 mg/dL to 600 mg/dL, as well as heart attacks early in life.Some people with familial hypercholesterolemia inherit two defective genes (one from each parent), a much rarer condition that affects 1 in 1 million people; they can have total cholesterol over 1000 mg/dL. Such high cholesterol can cause early death, often before age 20.