Read the following statements (A-D) carefully .
A. Causes the 25% loss of `CO_2` Fixed by Calvin - Benson cycle.
B. Operates in Chloroplasts, leaf peroxisomes and mitochondria.
C. Absent in photosynthetic bacteria.
D. Does not produce ATP.
Which light-dependent phenomenon has been described by the above statements ?

Options

A. Cyclic ETS
B. Photolysis of water
C. Photorespiration
D. Pentose phosphate pathway

Answer

To solve the question, we need to analyze each statement (A-D) and determine which light-dependent phenomenon they describe.

### Step-by-Step Solution:

1. **Understanding Statement A**:
- "Causes the 25% loss of CO2 fixed by Calvin-Benson cycle."
- This indicates a process that leads to a loss of carbon dioxide that has already been fixed during photosynthesis.

2. **Understanding Statement B**:
- "Operates in Chloroplasts, leaf peroxisomes, and mitochondria."
- This suggests that the phenomenon occurs in multiple organelles involved in photosynthesis and respiration.

3. **Understanding Statement C**:
- "Absent in photosynthetic bacteria."
- This implies that the process does not occur in certain types of bacteria that perform photosynthesis, which could hint at a more complex process.

4. **Understanding Statement D**:
- "Does not produce ATP."
- This indicates that the process is not energy-generating, which is a key characteristic of wasteful processes.

5. **Identifying the Phenomenon**:
- The statements collectively point towards "photorespiration."
- In photorespiration, the enzyme RuBisCO can bind to oxygen instead of carbon dioxide, leading to the production of phosphoglycolate instead of two molecules of 3-PGA, resulting in a loss of fixed carbon dioxide.
- This process occurs in chloroplasts, peroxisomes, and mitochondria, and it does not produce ATP.

### Conclusion:
The light-dependent phenomenon described by the statements A-D is **photorespiration**.

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