What is lipids? »Its Definition and Meaning [2019]

Lipids are a group of biological compounds that are classified together by their structure, usually apolar (carbon, hydrogen and oxygen), which makes them poorly soluble in water. They are mainly formed by acids fatty and glycerin or other alcohols.They are usually classified as glycerides (oils and fats), phospholipids, sphingolipids, glycolipids, cerids (waxes), steroids and terpenes. Fats and oils are the most abundant, these are the main constituents of their storage cells in animals and plants, and make up one of the body's important food reserves. The difference between fats and oils is very clear; the oil is a liquid at room temperature, while the fat is solid. You can extract these from animals and vegetables, thus obtaining substances such as corn, coconut, palm oil, tallow, bacon fat and butter.

From a chemical point of view, they are esters of fatty acids, formed by esterification reactions between them and an alcohol (glycerol) , to each molecule of glycerol are attached three fatty acids, from which the word triglycerides is derived.The fatty acids are formed by long-chain hydrocarbon chains, saturated (with simple bonds) or unsaturated (with double bonds). Animal fats tend to be saturated, while most oils are unsaturated (except palm oil, coconut oil and cocoa butter).

Fats are more concentrated in food energy (calories) than carbohydrates and protein as. For this reason, when small amounts of fat or oil are added to food, it significantly increases its caloric value.Fats in addition to storing energy for times of need, protects the organs of the body from damage body (kidneys, adrenal), isolates the body against the cold and helps to shape and develop the body to give it shape and beauty. Unfortunately, the excess calories or energy obtained by overeating, even if they come from Low-fat foods, also is stored as fat and produces obesity.

The other lipids also play fundamental roles as components of the membrane structure (phospholipids) ) ; the waxes, form protective surfaces in the leaves and fruits of the upper vegetables, in the cuticle of insects and in the epidermal formations of birds and mammals. Steroids, give rise to a huge variety of active biomolecules such as hormones (testosterone, estrogens) sterols, toxins and poisons , also include vitamin D; and finally, terpenes, essential oils that give their characteristic color to many fruits, rubber and some vitamins.