The molecular structure of penicillin antibiotic is

Options

A. Macrocyclic lactone
B. Glycoside linkage in amino sugar
C. `beta`-lactan ring
D. Polyaene and nonpolyaene

Answer

### Step-by-Step Solution:

1. **Understanding Penicillin**:
- Penicillin is the first antibiotic discovered by Sir Alexander Fleming. It is derived from the mold *Penicillium notatum*.

2. **Identifying the Structure**:
- The molecular structure of penicillin is characterized by specific components. The key features include:
- A **beta-lactam ring**
- A **thiazolidine ring**
- A **side chain**, specifically 6-aminopenicillanic acid.

3. **Function of the Beta-Lactam Ring**:
- The beta-lactam ring is crucial as it imparts the antibacterial activity of penicillin. This ring structure is essential for the antibiotic's function.

4. **Analyzing the Options**:
- The question provides four options regarding the molecular structure of penicillin:
- Option A: Macrocyclic lactone
- Option B: Glycoside linkage in amino sugar
- Option C: Beta-lactam ring
- Option D: Polyene and non-polyene
- From the discussion, it is clear that the beta-lactam ring is a defining feature of penicillin.

5. **Conclusion**:
- Based on the analysis, the correct answer to the question about the molecular structure of penicillin is **Option C: Beta-lactam ring**.