Let us take some examples to show you how easy and fun biology can be. Ok what shall we start with?

Right! Our bodies are made of "chemicals", of course, like anything else in the universe, so let us take the biochemistry of life. if that's OK with you guys! Proteins, first of all, are made of chains of amino acids linked together by peptide bonds - suppose you want to digest your sumptuous dinner composed of roast lamb and mint sauce (ooh - yummy!). There are, as you might guess, enzymes that can break peptide bonds between amino acids in the middle of the polypeptide chain (endopeptidases: Greek endo = inside) somewhere or near the ends (exopeptidases: Greek exo = outside).

Ok so far so good, but what is better to do first exo or endo? Think about it! If you break the bonds in the middle first, you will have more pieces therefore more ends for the "exo"s to work on so it will be more efficient - make sense? Of course - and although Jesus or Allah or Krishna did not do A level biology, he/she worked this out millions of years ago!

Yes, the endopeptidases (pepsin in the stomach; trypsin, chymotrypsin and elastase from the pancreatic juice) come before the aminopeptidases and carboxypeptidases [that break amino acids off at amino (-NH2) group and carboxyl (-COOH) group ends, respectively (enzymes secreted by the ileum, which you know comes after the stomach and duodenum, yeah?).

HOW CLEVER IS THAT? It is cool, right! Well done! It gets even easier and more interesting as we proceed - take your time and enjoy!