What does the ampr gene encode on the pARA-R plasmid?

What does the ampr gene encode on the pARA-R plasmid?

• A. Red fluorescent protein
• B. Arabinose metabolism protein
• C. Ampicillin resistance
• D. Promoter region for rfp

Answer: (C)

The ampr gene encodes a protein that gives bacteria resistance to ampicillin. It does this by producing beta-lactamase, an enzyme that cleaves the beta-lactam ring of ampicillin, inactivating the antibiotic. That lets cells carrying the plasmid grow on plates containing ampicillin, making ampr a convenient selectable marker for identifying successful plasmid uptake. Red fluorescent protein would require a gene for a fluorescent protein, arabinose metabolism would involve enzymes for sugar use, and a promoter region for rfp is not a gene encoding a resistance protein, so none of those would confer ampicillin resistance.

The ampr gene encodes a protein that gives bacteria resistance to ampicillin. It does this by producing beta-lactamase, an enzyme that cleaves the beta-lactam ring of ampicillin, inactivating the antibiotic. That lets cells carrying the plasmid grow on plates containing ampicillin, making ampr a convenient selectable marker for identifying successful plasmid uptake. Red fluorescent protein would require a gene for a fluorescent protein, arabinose metabolism would involve enzymes for sugar use, and a promoter region for rfp is not a gene encoding a resistance protein, so none of those would confer ampicillin resistance.