AP BIOLOGY

Detailed explanation-1: -A scientist used a plasmid that contained ampicillin resistance gene and lacZ gene as selectable markers.

Detailed explanation-2: -Ampicillin resistance gene is the most commonly used selection marker. When the plasmid containing this marker is transformed, it gives cells the ability to thrive in media containing ampicillin. The non-transformed cells die due to the presence of antibiotic.

Detailed explanation-3: -Ampicillin is commonly used as a selection marker since it binds to and inhibits the action of several enzymes that are involved in the synthesis of the cell wall. The ampicillin-resistant gene (ampR), on the other hand, catalyzes the hydrolysis of the B-lactam ring of ampicillin and naturally detoxifies the drug.

Detailed explanation-4: -The ampicillin resistance gene is known as amp or bla, which refers to beta-lactamase.

Detailed explanation-5: -The pBR322 plasmid is a commonly used cloning vector that contains both the ampicillin and tetracycline resistance genes as selectable markers.