In Lederberg's replica plating, streptomycn - resistant strain can develop by using

Options

A. Minimal medium and streptomycin
B. Complete medium and streptomycin
C. Only minimal medium
D. Only complete medium

Answer

**Step-by-Step Solution:**

1. **Understanding Lederberg's Replica Plating**:
- Lederberg's replica plating is a microbiological technique used to study bacterial mutations and antibiotic resistance. It involves transferring bacterial colonies from a master plate to a replica plate using a velvet cloth.

2. **Setting Up the Master Plate**:
- A master plate is prepared using a nutrient medium, such as agar, where different bacterial colonies grow. This plate serves as the source of bacterial colonies.

3. **Creating the Velvet Imprint**:
- A wooden block covered with a velvet cloth is pressed onto the master plate. The colonies on the master plate adhere to the velvet, creating an imprint.

4. **Transferring to the Replica Plate**:
- The wooden block with the velvet cloth is then pressed onto a new agar plate (the replica plate). This transfers the bacterial colonies from the velvet to the new plate, maintaining the spatial arrangement.

5. **Introducing Antibiotics**:
- In the next step, the replica plate can be supplemented with an antibiotic, such as streptomycin. This antibiotic will inhibit the growth of non-resistant bacteria.

6. **Identifying Resistant Strains**:
- After incubation, only those bacterial colonies that have developed resistance to streptomycin will grow on the replica plate. The colonies that cannot resist the antibiotic will not survive.

7. **Conclusion**:
- The experiment demonstrates that streptomycin-resistant strains can develop from the original population, indicating that resistance was present before exposure to the antibiotic. This supports the idea of natural selection, where only the resistant strains survive.

**Final Answer**: The correct option to develop a streptomycin-resistant strain in Lederberg's replica plating is to use a complete medium that allows for the growth of mutant strains of bacteria.

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