The two antibiotic resistance genes on vector pBR322 are for:

ampicillin and tetracycline

The answer is (a) ampicillin and tetracycline.

The vector pBR322 is a commonly used plasmid vector in genetic engineering and recombinant DNA technology. It contains two antibiotic resistance genes that allow for the selection of bacteria that have successfully taken up the vector and the foreign DNA of interest.

1. Ampicillin Resistance Gene: The pBR322 vector carries a gene that confers resistance to the antibiotic ampicillin. Bacteria containing this vector will be able to grow and survive in the presence of ampicillin because the gene produces an enzyme that inactivates the antibiotic, rendering it ineffective.
2. Tetracycline Resistance Gene: Additionally, pBR322 also carries a gene that provides resistance to the antibiotic tetracycline. Bacteria carrying this vector will be resistant to tetracycline, allowing them to grow and thrive in the presence of this antibiotic.

The presence of both antibiotic resistance genes enables researchers to use a two-step selection process to identify bacteria that have taken up the vector with the foreign DNA of interest. Bacteria are first grown on agar plates containing ampicillin. The bacteria that survive and grow on these plates are then transferred to plates containing tetracycline. Only the bacteria that are resistant to both antibiotics will be able to grow on the tetracycline plates, indicating that they have successfully incorporated the pBR322 vector and the foreign DNA. These bacteria can then be selected for further experimentation and analysis.