How are these chemicals affected by pH?

Question

I've looked everywhere and cannot find the information needed to complete a lab for school. The lab is meant to find the relationship between pH and photosynthesis. For the Extra Explorations portion of the lab, I need to find this information:

"Determine the exact chemicals involved in photosynthesis in green plant leaves. Find out how each chemical is affected by pH."

I have found the exact chemical involved with photosynthesis.

(Water, oxygen, carbon dioxide, RuBP, ATP, NADPH, Sugar, 3-phosphoglycerate, glyceraldehyde phosphate, 1-3-bisphosphoglycerate, glyceraldehyde-3-phosphate.)

I haven't been able to find how pH effects each of these chemicals. Any help would be greatly appreciated.

Also, I would really like to have a link to a website that I may go to so I can add it to my list of resources.

Thanks a million!

Answer 1

pH certainly has structural effects on most of the compounds you list.  That is because many of them are acids (the only one not an acid is sugar which I assume to mean glucose or sucrose).  So, the principles of simple acid-base chemistry apply to the ionization state of each compound.  Some of the compounds contain more than one ionizable group.  This important difference, however, is that different ionizable groups can have difference propensities to lose a H+ ion.  This is intrinsic to the concept of the equilibrium constant.  So, the net electrical charge on each of these photosynthetic metabolites will change with changes in pH.  pH is probably more important, however, in terms of its role in regulation of enzyme activities.  For more information check out this site:

http://photoscience.la.asu.edu/photosyn/...