This is the linoleic acid molecule. The radical oxidation that takes place in your body (oxygen rich environment) contributes to all of the negative downstream effects of seed oils. The radical oxidation is what ultimately poisons the mitochondria and leads to so much metabolic dysfunction in the fiat diet. 
Saturated fats lack the Carbon==Carbon double bond and are full of hydrogen molecules. This is why polyunsaturated (less hydrogen saturation) is so detrimental to human health.