Humans have a well defined range of ph tolerance; 7.35-7.45. in the context of molecules and macromolecules, what effects might you see from departure from normal ph?

Hello
The pH range of tolerance for humans is well defined and very small for a number of reasons.
First, we must understand that all biological reactions in our body are carried out by biological catalysts called enzymes. These enzymes operate under specific pH and and temperature conditions. Deviation from these conditions will result in inefficiency of the enzymes' functions. This may be observed macroscopic-ally as poor digestion among other things.
Next, an equilibrium is necessary for the movement of CO2 in red blood cells. CO2 is kept in equilibrium in the form of carbonic acid. This equilibrium may be disturbed by the change in pH; resulting in a difficulty to breathe. 
Other effects such as fatigue, headaches and nausea may also be observed as the blood circulates throughout your body and its functions will be impaired by the changed pH.