Question

43 multiple choice 1 point white colonies on a plate indicate the colonies contain nothing in them. the colonies are dead cells killed by antibiotics. they contain plasmid without the dna fragment to be cloned. they contain plasmid with the dna fragment to be cloned.

Explanation:

In molecular cloning (a technique in Biology, a subfield of Natural Science), when using a plasmid with a reporter gene (like lacZ for blue - white screening), white colonies typically result from the disruption of the reporter gene due to the insertion of the DNA fragment to be cloned. Colonies with plasmid without the insert will have an intact reporter gene and show the color of the reporter (e.g., blue in lacZ - based screening), while white colonies have the plasmid with the DNA fragment to be cloned (as the insert disrupts the reporter gene's function, preventing the color - producing reaction). The first option is incorrect as colonies are made of cells with plasmids. The second option is incorrect as white colonies in this context are not about antibiotic - killed cells. The third option would lead to a different color (e.g., blue) if the reporter gene is intact.

Answer:

D. They contain plasmid with the DNA fragment to be cloned.