Question

What are lipids? Describe classification of lipids with suitable examples.

Answer 1

Lipid Definition

A lipid is a fat-soluble molecule. To put it another way, lipids are insoluble in water but soluble in at least one organic solvent. The other major classes of organic compounds (nucleic acids, proteins, and carbohydrates) are much more soluble in water than in an organic solvent. Lipids are hydrocarbons (molecules consisting of hydrogen and oxygen), but they do not share a common molecule structure.

Lipids that contain an ester functional group may be hydrolyzed in water. Waxes, glycolipids, phospholipids, and neutral waxes are hydrolyzable lipids. Lipids that lack this functional group are considered nonhydrolyzable. Nonhydrolyzable lipids include steroids and the fat soluble vitamins A, D, E, and K.

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What Are Lipids? Definition and Examples

Introduction to Lipids in Chemistry

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Triglycerides are lipids that result from the reaction between glycerol and fatty acids.

Triglycerides. LAGUNA DESIGN / Getty Images

by

Anne Marie Helmenstine, Ph.D.

Updated January 28, 2019

Lipids are class of naturally-occurring organic compounds that you may know by their common names: fats and oils. A key characteristic of this group of compounds is that they are not soluble in water.

Here's a look at the function, structure, and physical properties of lipids.

Fast Facts: Lipids

A lipid is any biological molecule that is soluble in nonpolar solvents.

Lipids include fats, waxes, fat-soluble vitamins, sterols, and glycerides.

Biological functions of lipids include energy storage, cell membrane structural components, and signaling.

Lipid Definition

A lipid is a fat-soluble molecule. To put it another way, lipids are insoluble in water but soluble in at least one organic solvent. The other major classes of organic compounds (nucleic acids, proteins, and carbohydrates) are much more soluble in water than in an organic solvent. Lipids are hydrocarbons (molecules consisting of hydrogen and oxygen), but they do not share a common molecule structure.

Lipids that contain an ester functional group may be hydrolyzed in water. Waxes, glycolipids, phospholipids, and neutral waxes are hydrolyzable lipids. Lipids that lack this functional group are considered nonhydrolyzable. Nonhydrolyzable lipids include steroids and the fat soluble vitamins A, D, E, and K.

Examples of Common Lipids

There are many different types of lipids. Examples of common lipids include butter, vegetable oil, cholesterol and other steroids, waxes, phospholipids, and fat-soluble vitamins. The common characteristic of all of these compounds is that they are essentially insoluble in water yet soluble in one or more organic solvents.