Your blood glucose is approximately 5 mM, but the intracellular concentrations within different cells/tissues varies quite a bit.
For example, in muscle cells glucose levels are typically ten times less than this.
[A] Why is this the case for muscle cells?
[B] Why, given that glucose needs to be converted to glucose 6 phosphate by your cells, is glucose rather than glucose 6-phosphate clinically administered?
[C] PFK-1 shows an interesting dependency on ATP concentration, namely the activity first goes up, reaches a maximum value, and then decreases as the ATP concentrations goes up (to near zero). Provide a plausible explanation for this behavior, paying attention to a molecular explanation as to what its going on, on the enzyme itself.
[D] Finally, this relationship between ATP concentration and observed velocity is modulated by ADP; meaning, at low ADP the decreased velocity at higher ATP concentrations occurs at lower ATP concentrations, than at high ADP concentrations. Explain this result in the context of your response to part C.