What do you mean by Zwitter ion ?

Explanation

### Step-by-Step Solution:

1. **Definition of Zwitterion**: A zwitterion is a molecule that has both positive and negative charges but is overall electrically neutral.

2. **Structure of Amino Acids**: Amino acids are the primary examples of zwitterions. They contain two functional groups: an amino group (-NH2) which can accept a proton (H+) and a carboxylic acid group (-COOH) which can donate a proton.

3. **Ionizable Nature**: The zwitterionic nature of amino acids is due to their ability to ionize depending on the pH of the environment. At different pH levels, the amino group can be protonated (NH3+) or deprotonated (NH2), and the carboxylic acid group can be ionized (COO-).

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