The bicarbonate system in vivo

The lumped pK for the bicarbonate buffer system, pK = - og(KhK2), is approximately 6.18. Thus the pH may be expressed  

Carbon dioxide levels in the blood vary with the rate of respiration, while bicarbonate concentration is regulated primarily by the kidney [75]. Thus the pH of the blood is maintained by the coordinated function of the lungs and the kidneys in maintaining the ratio [HC03 ]/[C02] at a value of approximately 18 [75], 

This chapter has presented the basics of how thermodynamics are treated for biochemical systems, with an emphasis on the impact of pH and ion binding on apparent equilibria and Gibbs free energy functions. This field owes much to the work of Robert Alberty an extensive study of the field is presented in Alberty s text, Thermodynamics of Biochemical Systems [4], In our study of the theory and simulation of biochemical systems, we will usually be concerned with biochemical reactants such as ATP and ADP, although the detailed breakdown of these reactants into individual species will be important for many applications. 

1 Make a plot of the molar fractions of the species H2ADP-, 11 ADP2, and ADP3- as a function of pH, given the pK values listed in Table 2.1. 

3 There are conservation statements for total magnesium and potassium concentrations that are analogous to that for hydrogen ion of Equation (2.20). Write the potassium and magnesium conservation statements in terms of the binding polynomials. 

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