What are the types of fatty acids?

Fatty acids are classified into 4 main types: saturated, polyunsaturated, monounsaturated, and trans fats. 

1. Monounsaturated fatty acids have a single carbon-carbon double bound located at differing areas of the fatty acid chain. These fatty acids are typically between 16-22 carbons long, and have a cis double bond, giving the molecule a bent shape. 
2. Polyunsaturated fatty acids consist of multiple double bonds. If the first double bond sits between the third and fourth or sixth and seventh carbon molecules from the carbon-oxygen bond, it is known as an omega-3 and omega-6 fatty acid, respectively. Polyunsaturated fatty acids are vital for brain function and cell growth (as the body cannot naturally produce them) and are found exclusively in plants and phytoplankton. 
3. Saturated fats contain 12-22 carbon molecules and consist of hydrocarbon chains bound together exclusively via single bonds. These fatty acids are typically straight chains composed of an even quantity of carbon molecules. The end of a saturated fatty acid consists of a carbon  which is double bonded to an oxygen molecule and single bonded to a hydroxyl group. Saturated fats are considered to be unhealthy (as excess consumption can increase cholesterol and risk of cardiovascular disease), and are typically solid at room temperature. 
4. Trans fats are a type of unsaturated fats, with the key difference that they consist of trans double bonds instead of cis bonds; a trans bond forms a straight chain. These types of fats may either be polyunsaturated or monounsaturated. A diet high in trans fat is also considered unhealthy as it increases the risk for atherosclerosis and cardiovascular disease.