Question

Which of the following options correctly match the name of gene and its function in cloning vector pBR322?

• A. Cla I - Acts as selectable marker to identify non-transformants
• B. ampsuperscript{r} - Codes for plasmid amplifying enzymes
• C. rop - Codes proteins required for plasmid replication
• D. ori - Controls plasmid size

Hint:

In plasmid vectors, focus on the function of selectable markers (e.g., ampsuperscript{r}), replication origin (ori), and regulatory genes (like rop) to understand their role in cloning and amplification.

Answer 1

The Correct Option is C

Step 1: Understand components of pBR322. 
pBR322 is a widely used plasmid vector in genetic engineering. It contains: ampsuperscript{r}: Provides resistance to ampicillin (used as a selectable marker, not for amplifying enzymes).
Cla I: This is a restriction enzyme recognition site, not a gene, and doesn’t act as a selectable marker.
ori: Origin of replication, which controls the initiation of plasmid replication (not the plasmid size).
rop: Encodes a protein involved in regulating plasmid copy number, indirectly supporting replication. 
Step 2: Match the correct pair. 
Only rop correctly matches with “codes proteins required for plasmid replication.”