Lípido

Lípido is a broad term for a class of organic compounds that are generally insoluble in water but soluble in organic solvents. This insolubility in water is due to their nonpolar nature, meaning they are composed primarily of carbon and hydrogen atoms arranged in long hydrocarbon chains. Lipids play crucial roles in biological systems, serving as energy storage molecules, structural components of cell membranes, and signaling molecules.

There are several major categories of lipids. Triglycerides, the most abundant type of lipid in the diet, are formed from a glycerol molecule bonded to three fatty acid chains. They are a primary form of energy storage in animals and plants. Phospholipids are similar to triglycerides but have a phosphate group attached to one of the fatty acid positions, making them amphipathic – having both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions. This property is essential for forming the lipid bilayer that makes up cell membranes. Steroids, another important class, are characterized by a distinct four-ring structure. Cholesterol, a type of steroid, is a vital component of animal cell membranes and a precursor for steroid hormones like testosterone and estrogen. Other lipids include waxes, which provide waterproofing, and fat-soluble vitamins like A, D, E, and K, which are essential for various physiological processes. Lipids are digested and absorbed in the digestive system, often requiring bile salts to emulsify them for efficient breakdown and absorption.