Amino acids usually exist in the form of Zwitter ions. This mean that they consist of

Options

A. the basic `NH_(2)` groups and acidic COOH group
B. the basic `NH_(3)^(+)` group and the acidic `COO^(-)` group
C. basic `COO^(-)` group & acidic `NH_(3)^(-)` group
D. None of the above

Answer

To answer the question about the structure of amino acids in their zwitterionic form, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Amino Acids**:
- Amino acids are organic compounds that serve as the building blocks of proteins. They contain both an amino group (-NH2) and a carboxylic acid group (-COOH).

2. **Structure of Amino Acids**:
- The general structure of an amino acid can be represented as:
\[ \text{R-CH(NH2)-COOH} \]
- Here, R represents the variable side chain that differentiates one amino acid from another.

3. **Zwitterion Formation**:
- A zwitterion is a molecule that has both positive and negative charges but is overall electrically neutral.
- In amino acids, the amino group can accept a proton (H+) to become positively charged (-NH3+), while the carboxylic acid group can donate a proton to become negatively charged (-COO-).

4. **Charge Distribution**:
- In a zwitterionic form, the amino acid exists with the following charges:
- The amino group becomes positively charged: \(-NH3^+\)
- The carboxylic group becomes negatively charged: \(-COO^-\)

5. **Conclusion**:
- Therefore, in the zwitterionic form, amino acids consist of both a basic group (the amino group, which is positively charged) and an acidic group (the carboxylic group, which is negatively charged).

### Final Answer:
Amino acids usually exist in the form of zwitter ions, which means they consist of a basic amino group (-NH3+) and an acidic carboxylic group (-COO-).

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