Fatty acid metabolism: A metabolic verse

In beta oxidation, It just occurred to me The process all takes place between The carbons 2 and 3 Two hydrogens are first removed For FADH2 Then water adds across the bond, The H to carbon two Hydroxyl oxidation's next, Reducing NAD Then thiolase catalysis Dissects the last two C's The final products are, of course, All acetyl-CoAs Unless there were odd carbons, thence Propionyl-CoA For fatty acid synthesis One cycle's energy Takes NADPH times two Plus one lone ATP Each anabolic cycle starts With carbons one two three Yet products of reactions number carbons evenly The answer is that CO2 Plays peek-a-boo like games By linking to an Ac-CoA 1† Then popping off again The next three operations Change double bonds it's clear Reduction, dehydration and Then hydrogens appear The cycle after seven rounds Gives 16 carbon chains The links are saturated and No double bond remains For them desaturases toil Creating bonds of cis The animals get delta nine But no more go past this The synthesis of longer ones Eicosanoidic fun Is thanks to elongases in The e. reticulum