Which of the following is incorrect match between amino acid and its nature?

Options

A. Aspartic acid - Acidic amino acid
B. Arginine - Basic amino acid
C. Tryptophan - Heterocyclic amino acid
D. Isoleucine - Neutral amino acid

Answer

To determine which of the following is an incorrect match between an amino acid and its nature, we will analyze each option step by step.

### Step 1: Analyze Option 1 - Aspartic Acid
- **Amino Acid**: Aspartic Acid
- **Nature**: Acidic Amino Acid
- **Explanation**: Aspartic acid has a carboxyl group (-COOH) in its side chain, which gives it acidic properties. Therefore, this match is correct.

### Step 2: Analyze Option 2 - Arginine
- **Amino Acid**: Arginine
- **Nature**: Basic Amino Acid
- **Explanation**: Arginine contains a guanidinium group in its side chain, which makes it basic. Thus, this match is also correct.

### Step 3: Analyze Option 3 - Tryptophan
- **Amino Acid**: Tryptophan
- **Nature**: Heterocyclic Amino Acid
- **Explanation**: Tryptophan is known for having an indole ring, which is an aromatic structure. It is classified as an aromatic amino acid, not a heterocyclic amino acid. Therefore, this match is incorrect.

### Step 4: Analyze Option 4 - Isoleucine
- **Amino Acid**: Isoleucine
- **Nature**: Neutral Amino Acid
- **Explanation**: Isoleucine is a branched-chain amino acid that does not carry a charge at physiological pH, making it neutral. Thus, this match is correct.

### Conclusion
After analyzing all options, the incorrect match is:
- **Option C: Tryptophan - Heterocyclic Amino Acid** (This should be Aromatic Amino Acid).

### Final Answer
The incorrect match between amino acid and its nature is **Option C**.

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