Which gene fragments are present in the recombinant plasmid used in this experiment?

Which gene fragments are present in the recombinant plasmid used in this experiment?

• A. lacZ fragment and GFP fragment
• B. pBAD-rfp fragment
• C. ampR-ori-araC fragment
• D. pBAD-rfp fragment and ampR-ori-araC fragment

Answer: (D)

In this kind of recombinant plasmid, you need both a reporter cassette and the backbone that allows replication and selection. The pBAD-rfp fragment provides the reporter—the red fluorescent protein under the pBAD promoter, which is inducible by arabinose. The ampR-ori-araC fragment supplies the backbone elements: ampR for antibiotic resistance, ori for plasmid replication, and araC to regulate the pBAD promoter. Together they describe the plasmid used in the experiment. The other options don’t fit as well because they either include only the reporter without the necessary backbone (which would prevent plasmid propagation and selection) or only backbone elements without a reporter gene. lacZ and GFP would imply different reporters, not the pBAD-driven RFP system described here.

In this kind of recombinant plasmid, you need both a reporter cassette and the backbone that allows replication and selection. The pBAD-rfp fragment provides the reporter—the red fluorescent protein under the pBAD promoter, which is inducible by arabinose. The ampR-ori-araC fragment supplies the backbone elements: ampR for antibiotic resistance, ori for plasmid replication, and araC to regulate the pBAD promoter. Together they describe the plasmid used in the experiment.

The other options don’t fit as well because they either include only the reporter without the necessary backbone (which would prevent plasmid propagation and selection) or only backbone elements without a reporter gene. lacZ and GFP would imply different reporters, not the pBAD-driven RFP system described here.