What is cholesterol?

Essay by y2kooladamJunior High, 9th gradeA+, September 2003

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While cholesterol has a bad reputation for clogging up arteries and causing heart disease, this fatty molecule is an essential part of all cell membranes. Scientists have now found to their surprise that cholesterol may also regulate when and where nerve cells in the brain form the vital junctions known as synapses.


Cholesterol is a waxy fat that is present in all human beings. Two sources contribute to the amount of cholesterol in the human body. First, the liver manufactures about 80 percent of it. Second, people consume it by eating animal products such as meat, eggs and dairy products. Cholesterol is carried through the bloodstream by certain proteins (apolipoproteins). When these proteins wrap around cholesterol and other types of fats (lipids)to transport them through the bloodstream, the resulting "packages" are called lipoproteins. Cholesterol There are four different types of lipoproteins that carry cholesterol through the bloodstream:

* High-density lipoproteins (HDL), which are associated with "good" cholesterol.

* Low-density lipoproteins (LDL), which are associated with "bad" cholesterol.

* Very-low-density lipoproteins (VLDL), which are associated with "very bad" cholesterol.

* Chylomicrons, which only carry a small percentage of cholesterol. Chylomicrons are mostly rich in another type of fat (lipid) called triglycerides.

High levels of LDL cholesterol have been associated with hardened arteries (atherosclerosis) and coronary artery disease. In contrast, high levels of HDL cholesterol have been shown to reduce some of the harmful effects of LDL cholesterol.


High cholesterol is one of the major risk factors for heart disease.

Source: The National Institutes of Health / National Heart, Lung, and Blood Institute (US)

high cholesterol levels can lead to cardiovascular disease, for example heart attack and stroke, which claims a life every 33 seconds

cholesterol: a waxy, fat-like substance present in every cell in the body and in...