Question

The inhibiting effect of oxygen in $C_3$ plants on photosynthesis is

• A. Solarization
• B. Photo-oxidation
• C. Warburg effect
• D. None of the above

Answer 1

The correct option is C Warburg effect

Warburg effect is the decrease of photosynthesis by high oxygen concentrations. Oxygen is a competitive inhibitor of the carbon dioxide fixation by RuBisCO, which initiates photosynthesis. Furthermore oxygen stimulates photo respiration, which reduces photosynthetic output. These two mechanisms working together are responsible for the Warburg effect. This happens in $C_3$ plants. Thus, option C is correct.
Photo oxidation means knock out of electrons from a chemical compound in the presence of light by the high energy photons striking the compound. Thus, option B is wrong.
Solarization is the inhibition of photosynthesis at very high light intensities, owing mainly to the photo-oxidation of certain of the compounds involved. Thus, option A is wrong.