What is the correct fate of ammonium ions in plants ?

Options

A. It undergoes transamination with alpha ketogutaric acid to form glumate acid which further undergoes reductive amination to form other amino acids
B. It undergoes reductive amination with alpha ketoglutaric acid to glumatine which further undergoes transamination to form other amino acids .
C. It undergoes transamination with alpha ketogutaric acid to glutamine which further undergoes reductive amination to form other amino acids
D. It undergoes reductive amination with alpha ketoglutaric acid to glutamate which further undergoes transamination to form other amino acids .

Answer

To determine the correct fate of ammonium ions in plants, we can break down the process into several key steps:

### Step-by-Step Solution:

1. **Nitrogen Fixation**:
- In plants, particularly leguminous plants, nitrogen fixation occurs where atmospheric nitrogen (N₂) is converted into ammonia (NH₃). This is the initial step in utilizing nitrogen for plant growth.

2. **Formation of Ammonium Ions**:
- Ammonia (NH₃) can easily combine with hydrogen ions (H⁺) in the soil to form ammonium ions (NH₄⁺). This protonation is crucial because ammonium ions are the form that plants can readily absorb.

3. **Toxicity of Ammonium Ions**:
- Both ammonia and ammonium ions are toxic to plants if not processed quickly. Therefore, they must be converted into less toxic forms.

4. **Reductive Amination**:
- The first step in processing ammonium ions is reductive amination. Here, ammonium ions combine with alpha-ketoglutarate (a keto acid) to form glutamic acid. In this reaction, glutamate acts as an amino donor, providing the amino group.

5. **Transamination**:
- Following the formation of glutamic acid, transamination occurs. This process involves transferring the amino group from glutamic acid to other keto acids, resulting in the formation of various amino acids.

6. **Final Outcome**:
- Ultimately, the fate of ammonium ions in plants is that they are converted into amino acids, which are essential for protein synthesis and other metabolic processes.

### Conclusion:
The correct fate of ammonium ions in plants involves their conversion into glutamic acid through reductive amination, followed by their involvement in transamination to form other amino acids.