Which type of fatty acids do trans isomers belong to?

Trans isomers specifically belong to the category of unsaturated fatty acids. This is because unsaturated fatty acids contain one or more double bonds in their hydrocarbon chain. In the case of trans fatty acids, these double bonds occur in a specific geometric configuration that makes them different from their cis counterparts, which have the hydrogen atoms on the same side of the double bond.

Trans fatty acids are often found in partially hydrogenated oils, where the process of hydrogenation converts some of the unsaturated fats into trans fats. While both saturated and unsaturated fatty acids are components of dietary fats, it is the presence of a double bond that characterizes unsaturated fatty acids. Saturated fatty acids, on the other hand, contain no double bonds and are fully saturated with hydrogen atoms.

Polyunsaturated and monounsaturated fatty acids are specific subsets of unsaturated fatty acids, with polyunsaturated having multiple double bonds and monounsaturated having just one. Trans isomers do not fit solely into these categories as they can include specific trans configurations of both monounsaturated and polyunsaturated fatty acids, thus reinforcing their classification under the broader category of unsaturated fatty acids.