D-Alanine differs from L - Alanine with respect to

Options

A. configuration
B. chemical formula
C. number of `-NH_(2)` groups
D. number of -COOH groups

Answer

To answer the question "D-Alanine differs from L-Alanine with respect to," we can follow these steps:

### Step 1: Understand the Structure of Alanine
- Alanine is an amino acid with the general formula \( \text{C}_3\text{H}_7\text{N}\text{O}_2 \). It has a central carbon atom (the alpha carbon) bonded to an amino group (\(-\text{NH}_2\)), a carboxyl group (\(-\text{COOH}\)), a hydrogen atom, and a variable side chain (in the case of alanine, this is a methyl group \(-\text{CH}_3\)).

### Step 2: Identify the Forms of Alanine
- There are two enantiomers of alanine: D-Alanine and L-Alanine. These are stereoisomers that are mirror images of each other.

### Step 3: Determine the Key Difference
- The primary difference between D-Alanine and L-Alanine lies in their spatial arrangement around the chiral carbon atom. This difference is referred to as "configuration."

### Step 4: Analyze the Chemical Formula
- Both D-Alanine and L-Alanine have the same molecular formula, which is \( \text{C}_3\text{H}_7\text{N}\text{O}_2 \). Therefore, they do not differ in terms of their chemical formula.

### Step 5: Compare Functional Groups
- Both forms of alanine contain the same number of amino groups (\(-\text{NH}_2\)) and the same number of carbon and hydrogen atoms. Hence, they do not differ in the number of NH2 groups or CH groups.

### Conclusion
- The only distinguishing factor between D-Alanine and L-Alanine is their configuration, as they are non-superimposable mirror images (enantiomers).

### Final Answer
D-Alanine differs from L-Alanine with respect to configuration.

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