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Title: discuess the process of DNA molecules base-pairing in thermodynamic terms Post by: roxana90 on Sep 19, 2010 If two single-stranded DNA molecules with complementary sequences are mixed
in solution under physiological conditions (as found in a cell), they will base-pair to form a doubled-stranded molecule. Briefly discuss this process in thermodynamic terms. Your answer should include the words “spontaneous,” “Gibbs free energy,” “entropy,” and enthalpy. Title: Re: discuess the process of DNA molecules base-pairing in thermodynamic terms Post by: bio_man on Sep 20, 2010 The DNA spontaneously folds into its double helical structure due to complementary base pairing via hydrogen bonds.
A positive change in Gibbs free energy means the reaction is not thermodynamically favored to proceed in the direction indicated. Due to complementary base pairing, their will likely be a negative change, and thus it is thermodynamically favoured. Low entropy means a low degree of randomness. When the DNA strands come together, they amount of entropy decreases. Not too sure about enthalpy though! Title: Re: discuess the process of DNA molecules base-pairing in thermodynamic terms Post by: karim89 on Sep 24, 2010 well if we use the relation :
change in Gibbs free energy = change in enthalpy - temperature*change in entropy if the change in entropy is negative, then the change in enthalpy should also be negative to obtain a negative change in Gibbs free energy. change in enthalpy < temperature*change in entropy |