What does the bitten apple in the Apple Computers logo signify?

The original was a quotation by Wordsworth, inscribed into the logo: “Newton – a mind forever voyaging through strange seas of thought”. That was changed by designer Rob Janoff into a multi-coloured bitten apple – the “rainbow apple” – to commemorate the discoveries of gravity (the apple) and separation of light (colours) done by Isaac Newton. Besides, Alan Turing, the father of modern computing, committed suicide using a cyanide-laced apple. In 1997, Steve Jobs decided to replace this apple by a solid one.