Isoprene itself does not undergo the building process, but rather activated forms, isopentenyl pyrophosphate (IPP or also isopentenyl diphosphate) and dimethylallyl pyrophosphate (DMAPP or also dimethylallyl diphosphate), are the components in the biosynthetic pathway. IPP is formed from acetyl-CoA via the intermediacy of mevalonic acid in the HMG-CoA reductase pathway . An alternative, totally unrelated biosynthesis pathway of IPP is known in some bacterial groups and the plastids of plants, the so-called MEP(2-Methyl-D-erythritol-4-phosphate)-pathway, which is initiated from C5-sugars. In both pathways, IPP is isomerized to DMAPP by the enzyme isopentenyl pyrophosphate isomerase.
Much of the irony at the end of the novel stems from Golding’s portrayal of the naval officer. Although the naval officer saves Ralph, the ending of Lord of the Flies still is not particularly happy, and the moment in which the officer encounters the boys is not one of untainted joy. The officer says that he is unable to understand how upstanding British lads could have acted with such poor form. Ironically, though, this “civilized” officer is himself part of an adult world in which violence and war go hand in hand with civilization and social order. He reacts to the savage children with disgust, yet this disgust is tinged with hypocrisy. Similarly, the children are so shocked by the officer’s presence, and are now psychologically so far removed from his world, that they do not instantly celebrate his arrival. Rather, they stand before him baffled and bewildered. Even Ralph, whose life has literally been saved by the presence of the ship, weeps tears of grief rather than joy. For Ralph, as for the other boys, nothing can ever be as it was before coming to the island of the Lord of the Flies.