Suppose the gene of interest is inserted as Pstl site in pBR322, the resulting plasmid will confer resistance to :

Options

A. Ampicillin
B. Penicillin
C. Ampicillin and tetracycline
D. Tetracycline

Answer

To solve the question regarding the resulting plasmid after inserting a gene of interest at the PstI site in pBR322, we can follow these steps:

### Step 1: Understand the Structure of pBR322
pBR322 is a plasmid that contains genes that confer resistance to two antibiotics: ampicillin and tetracycline. It also has a replication origin (ORI) that allows it to replicate within a bacterial host.

**Hint:** Familiarize yourself with the components of plasmids, especially the functions of antibiotic resistance genes.

### Step 2: Identify the Insertion Site
The question specifies that the gene of interest is inserted at the PstI site. This is a specific location within the plasmid where the DNA can be cut and a new piece of DNA can be inserted.

**Hint:** Know that restriction enzymes like PstI create specific cuts in the DNA, allowing for the insertion of foreign DNA.

### Step 3: Determine the Effect of Insertion on Resistance Genes
Inserting the gene of interest at the PstI site will disrupt the ampicillin resistance gene. This means that the plasmid will no longer be able to confer resistance to ampicillin because the insertion interrupts the function of that gene.

**Hint:** When a gene is disrupted by an insertion, its function is typically lost.

### Step 4: Analyze the Remaining Resistance
Since the ampicillin resistance gene is disrupted, we need to check the status of the tetracycline resistance gene. The tetracycline resistance gene remains intact because the insertion did not affect it.

**Hint:** Always check which genes remain unaffected after an insertion.

### Step 5: Conclude the Resulting Resistance
As a result of the insertion at the PstI site, the plasmid will confer resistance to tetracycline but not to ampicillin.

**Hint:** Summarize the effects of genetic modifications to determine the final outcome.

### Final Answer
The resulting plasmid will confer resistance to tetracycline.