Consider the following enzymes
1. Glutamate dehydrogenase
2. Glutamine synthetase
3. Glutamate synthase
Which of these are concerned with ammonia assimilation?

Options

A. (a) 1 and 2
B. (b) 2 and 3
C. (c) 1 and 3
D. (d) 1, 2 and 3

Answer

To determine which of the enzymes listed are involved in ammonia assimilation, we can analyze each enzyme based on their functions and the biochemical processes they are part of.

### Step-by-Step Solution:

1. **Understanding Ammonia Assimilation**:
- Ammonia assimilation is the process by which ammonia (NH3) is converted into organic compounds, primarily amino acids, which are essential for plant growth and metabolism.

2. **Analyzing Glutamate Dehydrogenase**:
- Glutamate dehydrogenase catalyzes the reversible reaction between glutamate and α-ketoglutarate, utilizing ammonia and NAD(P)H. This reaction is significant in the assimilation of ammonia, particularly in the mitochondria.
- **Conclusion**: Glutamate dehydrogenase is involved in ammonia assimilation.

3. **Analyzing Glutamine Synthetase**:
- Glutamine synthetase catalyzes the conversion of glutamate and ammonia into glutamine, using ATP. This reaction occurs in the chloroplasts and is a key step in ammonia assimilation.
- **Conclusion**: Glutamine synthetase is involved in ammonia assimilation.

4. **Analyzing Glutamate Synthase**:
- Glutamate synthase facilitates the conversion of glutamine and α-ketoglutarate into two molecules of glutamate. This reaction also plays a role in incorporating ammonia into organic compounds.
- **Conclusion**: Glutamate synthase is involved in ammonia assimilation.

5. **Final Conclusion**:
- Since all three enzymes (Glutamate dehydrogenase, Glutamine synthetase, and Glutamate synthase) are involved in the process of ammonia assimilation, the correct answer is that all three enzymes are concerned with ammonia assimilation.

### Answer:
All three enzymes (1. Glutamate dehydrogenase, 2. Glutamine synthetase, and 3. Glutamate synthase) are concerned with ammonia assimilation.

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