Lecture 18 - Biological Molecules II Flashcards
what 5 different things can be found within the centre of DNA?
5 different heterocyclic bases
what are bases based on?
DNA bases are based on either the purine or pyrimidine structure tre
nucleotides in DNA and RNA are linked via:
phosphodiester bonds
what is the condensation product of an acid and an alcohol?
an ester
how many bonds do each of the specific base pairings make?
A—T makes only two hydrogen bonds
C—G makes three hydrogen bonds
why is DNA more stable than RNA?
DNA is more stable than RNA because the sugar present in RNA lacks the 2’ OH group
why is based catalysed hydrolysis rapid in RNA?
in RNA, base catalysed hydrolysis is rapid because of intermolecular nucleophilic attack
what is ATP in terms of its chemical origin?
ATP is an anhydride of phosphoric acid
what is an anhydride the product of?
an anhydride is the product of a condensation reaction between two molecules of an acid
characteristics of phosphate groups:
phosphate groups are stable anions and are also really good leaving groups
what can displace the triphosphate group in ATP?
soft nucleotides can displace the triphosphate group in ATP
what is ‘SAM’?
SAM is a biological methylating agent - its made by the sulphur atom of methionine displacing the phosphate group in ATP in an SN2 reaction
where do nucleophiles attack SAM?
nucleophiles attack SAM at the methyl group
how if caffeine made in coffee?
in the coffee plan theobromine is converted to caffeine using SAM
what can nucleoside analogues be used for?
nucleoside analogues can be used as antiviral drugs
