Question

A 5200-bp vector contains two BamHI sites 450-bp apart. A 1200-bp gene "X" with BamHI sites at ends is cloned after complete digestion. Size of the resultant plasmid?

• A. 5200-bp
• B. 6400-bp
• C. 5950-bp
• D. 6850-bp

Hint:

Result = (Original Vector - Removed Fragment) + New Insert.

Answer 1

The Correct Option is C

Step 1: Concept
Digestion with a restriction enzyme like BamHI at two sites removes the fragment between those sites.

Step 2: Analysis of Vector
Total vector = 5200 bp. Fragment removed = 450 bp.
Remaining vector backbone = $5200 - 450 = 4750 \text{ bp}$.

Step 3: Analysis of Insertion
Gene "X" (1200 bp) is inserted into the backbone.
Total plasmid = $4750 \text{ backbone} + 1200 \text{ gene} = 5950 \text{ bp}$.

Step 4: Conclusion
The resultant plasmid size is 5950 bp. Final Answer: (C)