You said : 1 glu ---> 2 lactates, delta Go = -45. What would
be the delta Go for 2 pyruvates from glucose?
The 45 figure was for the transformation without considering ATP coupling. I cited the
figure of -18 kcal/mole of glucose in the lecture and handout, for the reactions from
glucose to 2 pyruvates, including and taking into account the net production of 2 ATPs. If
you want to consider the standard free energy change of glucose to 2 pyruvates without
making ATP, it would be -18 -(7X2)= -32.
Why didn't you include the calculation of the energy ATP used in
the delta Go=-45? If you did, the anwer would be the NET energy and it is = -31?
Yes. I used the figure of 45 without the ATPs in order to calculate the efficiency of the
reaction in harnessing energy in the form of ATPs. So you had 45 to work with, you got 14
out of it, 31 were "left over," assuring that the reaction will still go far to
the right even after the coupling to the production of 2 ATPs.