Cholesterol comprises carbon, hydrogen, and oxygen. It is a waxy, fatty substance that is solid and white or light yellow. Its chemical formula is C27H46O. This means it has 27 atoms of carbon, 46 of hydrogen, and one of oxygen.
Cholesterol has several functions. It is an important component of the cell membrane, and the body uses it to make bile salts, vitamin D, and hormones, such as estrogen and testosterone.
Read more to learn more about the structure of cholesterol, its types, and its function.
Cholesterol is a waxy, fat-like substance that:
- is white or faint yellow
- is almost odorless
- has a solid rather than liquid consistency
The body needs cholesterol to maintain a person’s health, but only in limited amounts.
Although the liver makes its own cholesterol, people can also consume it through animal foods such as meat, poultry, fish, eggs, and dairy.
The body makes all the cholesterol it needs, so health experts recommend eating as little dietary cholesterol as possible.
The chemical formula of cholesterol is C27H46O. This means it consists of 27 atoms of carbon, 46 atoms of hydrogen, and one atom of oxygen.
- a central sterol nucleus of four hydrocarbon rings, which are hydrogen and carbon atoms with a circular arrangement
- a hydrocarbon tail, a chain of hydrogen and carbon atoms at the end of a molecule
- a hydroxyl group, which is one hydrogen atom bonded to one oxygen atom
The four hydrocarbon rings join together in the middle of the compound. The hydrocarbon tail attaches to one end, and the hydroxyl group attaches to the other.
Both the sterol nucleus and hydrocarbon tail do not mix with water, so this structure cannot travel through the bloodstream alone. For this reason, cholesterol combines with proteins to create lipoproteins, which can travel through the blood to reach cells that need them.
Although people generally believe cholesterol is harmful, it has several important roles,
- A cell membrane component: Cholesterol is an important part of the cell membrane structure. It changes the fluid in the membrane, which can affect the internal cell environment. It also fosters transportation within the cell.
- A digestive aid: Cholesterol is a component of bile salt. The digestive system uses this to absorb fat-soluble vitamins A, D, E, and K.
- A precursor for important bodily substances: The body uses cholesterol to make:
- vitamin D, which plays a role in bone health
- steroid hormones, such as cortisol, which help the body respond to stress
- reproductive system hormones such as estrogen and testosterone
Cholesterol also plays a role in the immune system and brain synapses. These are points of contact between nerve cells in the brain.
There are two primary types of cholesterol: low-density lipoprotein (LDL) and high-density lipoprotein (HDL). While people often refer to LDL as “bad” cholesterol, HDL is known as “good” cholesterol.
Conversely, HDL reduces the buildup of plaque in blood vessels. It absorbs cholesterol and brings it to the liver, which removes it from the body.
Having high levels of HDL can reduce a person’s risk of a heart attack and stroke.
The structure of cholesterol
While cholesterol serves essential functions, the body makes all that it needs. Therefore,