The key difference between cis and trans fatty acids is that the cis fatty acids have two hydrogen atoms attached to the double bond in the same side of the carbon chain whereas the trans fatty acids have the two hydrogen atoms bonded to the double bond in the opposite sides of the carbon chain.
Fatty acids are carboxylic acids containing long aliphatic carbon chains that are either saturated or unsaturated. This means, the aliphatic chain may or may not contain double bonds between the carbon atoms. Cis and trans fatty acids are two forms of unsaturated fatty acids.
