The deficiencies of micronutrients not only affects growth of plants, but also vital functions such as photosynthetic and mitochondrial electron flow. Among the list given below, which group of three elements shall affect the most, both photosynthetic and mitochondrial electron transport ?

Options

A. Ca, K, Na
B. Co, Ni, Mo
C. Mn, Co, Ca
D. Cu, Mn, Fe

Answer

To solve the question regarding which group of three elements affects both photosynthetic and mitochondrial electron transport the most, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Processes**:
- Photosynthesis occurs in the chloroplasts, specifically in the thylakoid membranes where the light-dependent reactions take place.
- Mitochondrial electron transport occurs in the cristae of mitochondria, where the electron transport chain (ETC) is located.

2. **Identifying Micronutrients**:
- Micronutrients are essential elements required in small amounts for plant growth and development. Some important micronutrients include iron (Fe), copper (Cu), manganese (Mn), calcium (Ca), potassium (K), sodium (Na), cobalt (Co), and molybdenum (Mo).

3. **Role of Key Micronutrients**:
- **Iron (Fe)**: A crucial component of cytochromes in both photosynthesis and respiration. It plays a significant role in electron transport chains.
- **Copper (Cu)**: Another essential element that acts as a cofactor for various enzymes and is involved in electron transport.
- **Manganese (Mn)**: Functions as an activator for enzymes involved in photosynthesis, particularly in the water-splitting reaction during the light-dependent phase.

4. **Analyzing the Options**:
- We need to identify the group of three elements that includes iron, copper, and manganese, as these are directly involved in the electron transport processes in both photosynthesis and respiration.

5. **Conclusion**:
- The group of three elements that affects both photosynthetic and mitochondrial electron transport the most is **Copper (Cu), Iron (Fe), and Manganese (Mn)**. Therefore, the correct answer is option 4.

### Final Answer:
**The group of three elements that affects both photosynthetic and mitochondrial electron transport the most is Copper (Cu), Iron (Fe), and Manganese (Mn).**

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