Assertion: Except glycine, all naturally occurring `alpha`-amino acids are optically active.
Reason : All `alpha`-amino acids occurring naturally except glycine has at least one asymmetric carbon.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.

Answer

To solve the assertion and reason question, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
**Assertion:** Except glycine, all naturally occurring alpha-amino acids are optically active.

- **Understanding Alpha-Amino Acids:**
Alpha-amino acids have the general structure:
\[ \text{NH}_2 - \text{CH}(\text{R}) - \text{COOH} \]
where R represents a variable side chain.

- **Glycine Structure:**
Glycine is the simplest alpha-amino acid and has the structure:
\[ \text{NH}_2 - \text{CH}_2 - \text{COOH} \]
In this case, the R group is a hydrogen atom (H).

- **Chirality in Amino Acids:**
For a molecule to be optically active, it must have at least one chiral center (asymmetric carbon). A chiral center is a carbon atom that is bonded to four different groups.

- **Conclusion on Assertion:**
Since glycine has no chiral center (the carbon is bonded to two hydrogens), it is not optically active. All other naturally occurring alpha-amino acids have at least one chiral center due to their unique R groups. Therefore, the assertion is **true**.

### Step 2: Analyze the Reason
**Reason:** All alpha-amino acids occurring naturally except glycine have at least one asymmetric carbon.

- **Understanding Asymmetric Carbon:**
An asymmetric carbon is a carbon atom that has four different substituents. In the case of alpha-amino acids (other than glycine), the carbon atom attached to the amino group (NH2) and carboxylic group (COOH) also has a distinct R group.

- **Conclusion on Reason:**
Since all naturally occurring alpha-amino acids (except glycine) have an R group that is different from hydrogen, they possess at least one asymmetric carbon. Thus, the reason is also **true**.

### Step 3: Determine the Relationship
- The reason provided explains why the assertion is true. The presence of an asymmetric carbon in all amino acids except glycine directly leads to their optical activity.

### Final Conclusion
Both the assertion and reason are true, and the reason correctly explains the assertion.

### Answer:
**Both Assertion and Reason are True; Reason is the correct explanation of Assertion.**

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