Hello . 1) - i am having some problems with biochemistry (first month of first semester of first year of medical school) . the course contains a large number of spontaneous chemical reactions especially on -OH , -COOH , -COH ... groups on glucides , Amino acides and so on .... when i ask the professors they say that they don't have time to explain the foundations of those reactions and that i just need to memorise them the way they are . now they said that for me to understand this i need to look for : - notion of electronegativity - atomic models and electron distribution - nucleophile and electrophile components and why they are like that . and so on ... now i looked for this for sometime on the Net and i just don't seem to be able to find what i need . can someone please guide me to some good documents to explain these things ? 2) - a chiral molecule is a molecule that is not superposable with it's image in a mirror since it has no axe of symmetry , now the course then links this to Asymmetrical carbon atoms which is logical since a C that is linked to 4 different component always gives a Chiral molecule . now what if you would take a molecule like this one Code (Text): OH | CH3-C-H | H now that Carbon atom is not Asymmetrical , so the molecule is Achiral and it's not a chiral molecule , yet it fits the definition , that molecule is not superposable with it's image in a mirror . and if we take the D-glucose for example : (fisher representation) Code (Text): H - C = O | H - *C - OH | OH - *C - H | H - *C - OH | H - *C - OH | CH2OH (*C : asymmetrical carbon atom) if we change the configuration of a single *C the proprieties of the molecule change , yet what if we rotate the upper link , ( - COH : grouple aldehyde) that should not change the molecule and it's as if we didn't do a thing since that carbon atom n#1 is not asymetrical , even the configuration of the bottom CH2OH doesn't matter in stereo-isomerism . i don't understand this . i also have a problem with mutarotation and Anomers and the behavior of glucides in water , i think i would understand that if i understand the notions in 1)- . i am used to Math and physics and those were well founded for me so my mind accepted them , now though the quantity of information is big yet i don't understand the foundations , i can memorise it all as it is and just pass the exam but i know that's not good . thank you very much for your attention .