Choose the incorrect statement regarding `N_(2)` metabolism

Options

A. 16 ATPs are required for conversion of one molecule of nitrogen into ammonia
B. Nodule formation requires cytokinin and auxin
C. All twenty amino acid are formed from glutamic acid by transamination
D. Leghaemoglobin in synthesised by host with the help of bacteria

Answer

To solve the question regarding nitrogen metabolism, we need to analyze the statements provided and identify which one is incorrect. Here’s a step-by-step breakdown of the process:

### Step 1: Analyze the First Statement
**Statement:** "16 ATPs are required for the conversion of one molecule of Nitrogen into Ammonia."
- **Explanation:** The process of nitrogen fixation requires energy, and it is known that 16 ATP molecules are indeed used in the conversion of nitrogen gas (N₂) to ammonia (NH₃). This statement is correct.

### Step 2: Analyze the Second Statement
**Statement:** "Nodule formation requires cytokinin and auxin."
- **Explanation:** Nodule formation in legumes involves the interaction between rhizobium bacteria and the plant roots. Cytokinins and auxins are plant hormones that play a role in this process. Therefore, this statement is also correct.

### Step 3: Analyze the Third Statement
**Statement:** "All 20 amino acids are formed from glutamic acid by transamination."
- **Explanation:** Transamination is a process where an amino group is transferred from one amino acid to a keto acid. However, not all 20 amino acids can be synthesized solely from glutamic acid through transamination. Some amino acids are essential and cannot be synthesized by the organism. Thus, this statement is incorrect.

### Step 4: Analyze the Fourth Statement
**Statement:** "Leg haemoglobin is synthesized by the host plant with the help of bacteria."
- **Explanation:** Leghemoglobin is indeed synthesized by the host plant (legumes) and is important for maintaining low oxygen levels in the root nodules, which is crucial for the nitrogen-fixing bacteria. This statement is correct.

### Conclusion
After analyzing all the statements, the incorrect statement regarding nitrogen metabolism is:
**"All 20 amino acids are formed from glutamic acid by transamination."**