An acidic amino acid is

Options

A. Lysine
B. Glutamate
C. Aspartate
D. Both B and C.

Answer

To determine which amino acids are classified as acidic, we need to analyze the structures of the given amino acids: lysine, glutamate, and aspartate.

### Step 1: Understand the Structure of Amino Acids
Amino acids have a basic structure that includes:
- An amino group (-NH2)
- A carboxyl group (-COOH)
- A hydrogen atom
- A variable R group (side chain)

### Step 2: Analyze Each Amino Acid
1. **Lysine**:
- Structure: Contains one amino group (-NH2) and one carboxyl group (-COOH).
- Additional Group: Lysine has an extra amino group, which contributes to its basic nature.
- Conclusion: Lysine is a basic amino acid.

2. **Glutamate**:
- Structure: Contains one amino group (-NH2) and one carboxyl group (-COOH).
- Additional Group: Glutamate has an extra carboxyl group (-COOH), which can lose a proton (H+).
- Conclusion: Glutamate is an acidic amino acid.

3. **Aspartate**:
- Structure: Contains one amino group (-NH2) and one carboxyl group (-COOH).
- Additional Group: Aspartate also has an extra carboxyl group (-COOH), which can lose a proton (H+).
- Conclusion: Aspartate is an acidic amino acid.

### Step 3: Identify the Acidic Amino Acids
From the analysis:
- Lysine is basic.
- Glutamate is acidic.
- Aspartate is acidic.

### Final Answer
Both glutamate and aspartate are acidic amino acids. Therefore, the correct answer is **both B and C**.

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