What are acidic amino acids?

Explanation

**Step-by-Step Text Solution:**

1. **Definition of Amino Acids**: Amino acids are organic compounds that serve as the building blocks of proteins. Each amino acid contains at least one amino group (-NH2) and one carboxylic group (-COOH).

2. **Characteristics of Acidic Amino Acids**: Acidic amino acids are a specific type of amino acid that contains two carboxylic groups and one amino group. This structure allows them to donate protons (H+) in solution, which is a characteristic of acids.

3. **Charge at Physiological pH**: At physiological pH (around 7.4), acidic amino acids typically carry a negative charge. This is due to the ionization of the carboxylic groups, which can lose protons and become negatively charged.

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