Introduction to Cholesterol

Cholesterol originated from the Greek words chole, which means bile, stereos, which means solid, and the suffix -ol, which means alcohol. As a sterol, it is an organic compound and a form of lipid. It is also a structural part of the animal cell membrane that all animal cells can biosynthesize. Cholesteryl alcohol and cholesterin are two other cholesterol chemical names. The hydrogen bond donor and acceptor have property values of 1 and 1, respectively, and the rotatable bond count is 5.


Cholesterol is also a precursor for steroid hormones, bile acid, and vitamin D biosynthesis. Cholesterol is the most common sterol produced by all animals. Hepatic cells are the ones that generate the most in the vertebrates. With the exception of Mycoplasma, which needs cholesterol for growth, it is not present in prokaryotes (bacteria and archaea). This article will study cholesterol formula, cholesterol chemical name, Cholesterol Structure, properties of cholesterol, and cholesterol structure and function. 

Cholesterol Structure

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Properties of Cholesterol

IUPAC name

(3β)-cholest-5-en-3-ol

Cholesterol Molecular Formula/Cholesterol Chemical Formula

C27H46O

Molecular mass

386.664 g/mol

Melting point

148 to 150℃

Boiling Point

360℃

Density 

1.052 g/cm3

Solubility 

Soluble in acetone, benzene, ether, hexane

Solubility in water 

1.8 mg/L at 30℃

Appearance 

White Crystalline Powder


Cholesterol Structure and Function

  1. Membrane 

Cholesterol accounts for roughly 30% of all animal cell membranes. It is required for the construction and maintenance of membranes, as well as the modulation of membrane fluidity over a wide range of physiological temperatures. The hydroxyl groups of cholesterol molecules, as well as the polar heads of membrane phospholipids and sphingolipids, interact with water molecules surrounding the membrane, while the bulky steroid and hydrocarbon chains, as well as the nonpolar fatty-acid chains of the other lipids, are embedded in the membrane. Cholesterol enhances membrane packing by interacting with phospholipid fatty-acid chains, altering membrane fluidity, and maintaining membrane integrity so that animal cells do not need to erect cell walls (like plants and most bacteria). Animal cells can change shape and animals can move because the membrane is stable and strong without being rigid.

  1. Gates

Cholesterol plays a role in intracellular transport, cell signalling, and nerve conduction within the cell membrane. Cholesterol is needed for caveolae-dependent and clathrin-dependent endocytosis, as well as the structure and function of invaginated caveolae and clathrin-coated pits. Cholesterol controls the biological process of substrate presentation as well as the enzymes that use substrate presentation to activate themselves. (PLD2) is a well-known example of an enzyme that is activated by the presence of a substrate.

  1. Signalling

Cholesterol plays a role in cell signaling by assisting in the development of lipid rafts in the plasma membrane, which carry receptor proteins together with high concentrations of second messenger molecules. Cholesterol and phospholipids, both electrical insulators, can help speed up the propagation of electrical impulses along with nerve tissue in multiple layers. A myelin sheath, which is rich in cholesterol since it is derived from compacted layers of Schwann cell membrane, provides protection for many neuron fibres, allowing for more effective impulse conduction. Multiple sclerosis is thought to be caused by demyelination (the failure of some of these Schwann cells).

  1. Chemical Precursor

Cholesterol is a precursor molecule for many biochemical processes within cells. It is the precursor molecule for the synthesis of vitamin D and all steroid hormones, including the adrenal gland hormones cortisol and aldosterone, as well as the sex hormones progesterone, estrogens, and testosterone, and their equivalents, in the calcium metabolism.

  1. Metabolism

In the body, cholesterol is recycled. The liver converts cholesterol into biliary fluids, which are then processed in the gallbladder, which then excretes them into the digestive tract in a non-esterified form (via bile). Approximately half of the cholesterol excreted is reabsorbed into the bloodstream through the small intestine.


Transportation of Cholesterol

Cholesterol is only slightly soluble in water as an isolated molecule, making it hydrophilic. As a result, it dissolves in blood at very low concentrations. Cholesterol is packaged inside lipoproteins, complex discoidal particles with external amphiphilic proteins and lipids, whose outward-facing surfaces are water-soluble and inward-facing surfaces are lipid-soluble, in order to be transported effectively. This causes it to emulsify and pass through the bloodstream. Since unbound cholesterol is amphipathic, it is transported along with phospholipids and proteins in the monolayer surface of the lipoprotein particle. Cholesterol esters attached to fatty acids, on the other hand, are transported along with triglyceride within the lipoprotein.


Did You Know?

According to the lipid theory, high blood cholesterol levels cause atherosclerosis, which can lead to heart attacks, strokes, and peripheral artery disease. Higher blood LDL – especially higher LDL concentrations and smaller LDL particle size – contributes more to this process than the cholesterol content of HDL particles, so LDL particles are often referred to as "poor cholesterol." High levels of functional HDL, which can extract cholesterol from cells and atheromas, provide safety and are referred to as "healthy cholesterol" by the general public. These equilibriums are often determined by genetics, but they can be influenced by body structure, drugs, diet, and other factors.

FAQs (Frequently Asked Questions)

Question1: What are Cholesterol and Its Function?

Ans: Its primary purpose is to keep cell membranes intact and fluid, as well as to act as a precursor for the synthesis of essential substances such as steroid hormones, bile acids, and vitamin D.

Question2: Is Cholesterol Beneficial or Harmful?

Ans: Lipoproteins are two types of proteins that transport cholesterol in the body: the majority of your body's cholesterol is LDL (low-density lipoprotein), also known as "negative" cholesterol. High LDL cholesterol levels increase the risk of heart disease and stroke.

Question3: How is Cholesterol Produced in the Body?

Ans: The liver produces cholesterol, as do most other cells in the body. Lipoproteins, which are small 'couriers' in the blood, transport it. The body requires a small amount of blood cholesterol to: construct the structure of cell membranes.