The simplest known photosynthetic system is bacteriorhodopsin (BR) , a 26KD membrane protein found in halophilic bacteria. BR is a simple light-activated proton pump which translocates one H+ per photon absorbed. The protons are then used to synthesize ATP with a typical ATP synthase enzyme. The peak absorption of BR is in the green light range (565 nm photons).
a. If 3 H+/ATP is required for synthesis what is the % efficiency of this photosynthetic system? Assume the DGâ for ATP hydrolysis in -12 kcal/mol (-50. kJ/mol) under the real cellular conditions at 37oC.
b. Look up a value for the efficiency of a typical green plant (PSI and PSII) photosynthetic system. What is it (there are any different estimates out thereâpick one)? How does it compare? What are some of the disadvantages of the simple BR system as compared to the extremely complex green plant system?
The simplest known photosynthetic system is bacteriorhodopsin (BR) , a 26KD membrane protein found in halophilic bacteria. BR is a simple light-activated proton pump which translocates one H+ per photon absorbed. The protons are then used to synthesize ATP with a typical ATP synthase enzyme. The peak absorption of BR is in the green light range (565 nm photons).
a. If 3 H+/ATP is required for synthesis what is the % efficiency of this photosynthetic system? Assume the DGâ for ATP hydrolysis in -12 kcal/mol (-50. kJ/mol) under the real cellular conditions at 37oC.
b. Look up a value for the efficiency of a typical green plant (PSI and PSII) photosynthetic system. What is it (there are any different estimates out thereâpick one)? How does it compare? What are some of the disadvantages of the simple BR system as compared to the extremely complex green plant system?
