How many light quanta or photons are required for the synthesis of one `O_2` molecule during the process of photosynthesis ?

Options

A. 48
B. 1
C. 8
D. 12

Answer

To determine how many light quanta or photons are required for the synthesis of one O₂ molecule during photosynthesis, we can follow these steps:

### Step 1: Understand the process of photosynthesis
Photosynthesis occurs in two main stages: the light-dependent reactions and the light-independent reactions (Calvin cycle). The light-dependent reactions convert light energy into chemical energy, producing ATP and NADPH, and releasing oxygen as a byproduct.

### Step 2: Identify the role of photons
During the light-dependent reactions, photons (light quanta) are absorbed by chlorophyll and other pigments in the chloroplasts. This energy is used to split water molecules (H₂O) into oxygen (O₂), protons (H⁺), and electrons.

### Step 3: Determine the number of protons required
It is known that for the synthesis of one molecule of O₂, a certain number of protons (H⁺ ions) are required. In the process of photosynthesis, specifically during the photolysis of water, it is established that 8 protons are involved in the production of one O₂ molecule.

### Step 4: Relate protons to photons
Research indicates that for every 8 protons generated, 12 photons are typically required to facilitate the entire process of photosynthesis. However, the question specifically asks for the number of photons needed to produce one molecule of O₂.

### Step 5: Calculate the number of photons for one O₂ molecule
Based on the established relationship in photosynthesis, it is determined that 12 photons are needed to release one molecule of O₂.

### Conclusion
Thus, the final answer is that **12 photons** are required for the synthesis of one molecule of O₂ during photosynthesis.

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