Some anaerobic bacteria carry out anoxygenic photosynthesis using the net chemical conversion shown below:
6 CO₂ + 12 H₂S $\rightarrow$ C₆H₁₂O₆ + 6 H₂O + 12 S
The discovery of this type of photosynthesis provided evidence for which aspect of the photosynthetic process?

Question

Some anaerobic bacteria carry out anoxygenic photosynthesis using the net chemical conversion shown below:
6 CO₂ + 12 H₂S

\rightarrow

C₆H₁₂O₆ + 6 H₂O + 12 S
The discovery of this type of photosynthesis provided evidence for which aspect of the photosynthetic process?

Quizplus · Accepted Answer

The net chemical conversion shown in the question involves the use of COS (carbonyl sulfide) as the electron donor and not water. This demonstrates that anoxygenic photosynthesis can occur without the production of oxygen as a byproduct. This provides evidence for the fact that in oxygenic photosynthesis, the source of oxygen atoms is water, not carbon dioxide (option A).

Some Anaerobic Bacteria Carry Out Anoxygenic Photosynthesis Using the Net →\rightarrow→

Some Anaerobic Bacteria Carry Out Anoxygenic Photosynthesis Using the Net $\rightarrow$