Question

Which of the following is absent in pBR322?

• A. Origin of replication
• B. Restriction site
• C. T-DNA
• D. Antibiotic resistant genes

Hint:

Remember: pBR322 → Bacterial cloning vector; Ti plasmid (T-DNA) → Plant transformation.

Answer 1

The Correct Option is C

Step 1: Features of pBR322.
pBR322 is a commonly used cloning vector in bacteria. It contains:
- Origin of replication (ori).
- Restriction sites for cloning.
- Antibiotic resistance genes (ampicillin, tetracycline).
Step 2: Absent component.
T-DNA is specific to Agrobacterium Ti plasmid, used for plant transformation, not bacterial cloning vectors like pBR322.
Step 3: Conclusion.
Hence, T-DNA is absent in pBR322.