Lipid

Lipid

Common types of lipids

Lipids are a diverse group of biological molecules that are insoluble in water but soluble in nonpolar solvents. They play crucial roles in cell structure, energy storage, and signaling.

Classification

Lipids can be classified into several categories based on their structure and function:

Fatty Acids

Structure of a triglyceride

Fatty acids are carboxylic acids with long hydrocarbon chains. They can be saturated or unsaturated, depending on the presence of double bonds.

Glycerolipids

Glycerolipids include triglycerides, which are the main form of stored energy in animals. They consist of glycerol esterified with three fatty acids.

Phospholipids

Structure of phosphatidylethanolamine

Phospholipids are a major component of cell membranes. They contain a glycerol backbone, two fatty acid tails, and a phosphate group.

Sphingolipids

Structure of sphingomyelin

Sphingolipids are important components of the myelin sheath of nerve cells. They are based on a sphingosine backbone.

Steroids

Structure of cholesterol

Steroids have a characteristic four-ring structure. Cholesterol is a well-known steroid that is a precursor to many hormones.

Eicosanoids

Structure of prostacyclin

Eicosanoids are signaling molecules derived from arachidonic acid. They include prostaglandins, thromboxanes, and leukotrienes.

Terpenes

Structure of geraniol

Terpenes are a large and diverse class of organic compounds produced by a variety of plants. They are the primary constituents of essential oils.

Functions

Lipids serve several key functions in biological systems:

• Energy Storage: Lipids are a dense form of energy storage, providing more than twice the energy per gram compared to carbohydrates.
• Structural Components: Phospholipids and cholesterol are essential components of cell membranes, providing structural integrity and fluidity.
• Signaling Molecules: Lipids such as steroid hormones and eicosanoids play critical roles in cell signaling and regulation.

Related Pages

• Fatty acid
• Triglyceride
• Phospholipid
• Steroid
• Eicosanoid
• Terpene