Final answer:
The number of fragments produced when a recombinant plasmid is cut by the restriction enzyme abc1 depends on the number of recognition sites on the plasmid and the inserted DNA. Typically, if the plasmid and insert have one recognition site each, two fragments will result.
Step-by-step explanation:
When the recombinant plasmid is cut by the restriction enzyme abc1, the number of fragments produced can vary based on several factors, such as the number of abc1 recognition sites on the plasmid DNA and the presence of insert DNA within the plasmid. However, without specific information on the sequence of the plasmid and the exact cutting pattern of abc1, the expected number of fragments would be difficult to predict accurately. Generally, if the plasmid has a single abc1 site and an inserted foreign DNA fragment has no additional abc1 sites, you would normally expect two fragments after cutting with the enzyme. If the foreign DNA also contains abc1 sites, the number of fragments will increase. It's also important to note that different vectors and inserts may have unique restriction sites that will influence the final number of DNA fragments.