Fats, steroids and waxes are some of the most common types of lipids. Lipids are non-polar hydrocarbons because of the presence of non-polar carbon-carbon and carbon-hydrogen bonds in there structure.
Generally, polar molecules are soluble in water while non-polar molecules are insoluble in water, hence, lipids do not dissolve in water. There non-polarity also makes them a suitable component in the selectively permeable biological cell membrane.
