Wednesday, December 26, 2012

TERM: Cholesterol

Structure of the cholest-5-en-3β-ol (cholesterol)

Cholesterol is a molecule that is found in cells. It is a type of lipid which is a fat or fat-like molecule. Cholesterol is a soft waxy substance. Cholesterol is a special type of lipid that is called a steroid. Steroids are lipids that have a special chemical structure. This structure is made of four rings of carbon atoms. Cholesterol is found especially in animal fats.

Other steroids include hormone steroids like cortisol, estrogen, and testosterone. In fact, all steroid hormones are made from changing the basic chemical structure of cholesterol. When scientists talk about making one molecule from changing simpler ones, they sometimes call it synthesis.

Cholesterol is also necessary to the normal permeability and function of the membranes that surround cells. A diet high in saturated fats tends to increase blood cholesterol levels, whereas a diet high in unsaturated fats tends to lower blood cholesterol levels. Although some cholesterol is obtained from the diet, most cholesterol is made in the liver and other tissues.

Hypercholesterolemia means that cholesterol level is too high in the blood. Cholesterol levels that are high are possible precursors to heart disease.

Word List:
  • molecule: the smallest unit, consisting of a group of atoms, into which a substance can be divided without a change in its chemical nature
  • waxy: looking or feeling like wax
  • synthesis: the natural chemical production of a substance in animals and plants
  • permeability: allowing a liquid or gas to pass through
  • precursor: a person or thing that comes before somebody/something similar and that leads to or influences its development
 = cholesterol
 = molecule
 = lipid
 = steroid
 = hormone
 = cortisol
 = estrogen
 = testosterone
 = synthesis
 = permeable
 = hypercholesterolemia
 = precursor

References: - cholesterol - cholesterol