Final answer:
The F-plasmid is a DNA element in bacteria such as E. coli, ranging from 5,000 to 400,000 base pairs. It plays a crucial role in bacterial conjugation, allowing the transfer of genetic material between cells, which is key for genetic mapping. The size range is broad, and specific mapping depends on the bacterial strain.
Step-by-step explanation:
The F-plasmid, found in bacteria like Escherichia coli (E. coli), is a piece of DNA that can replicate independently of the bacterial chromosome. Naturally occurring bacterial plasmids, such as the F-plasmid, can range in size from about 5,000 to 400,000 base pairs. The F-plasmid is known to have a significant role in bacterial conjugation, where an F+ (F-plasmid carrying) bacterial cell can transfer genetic material to an F- (plasmid-free) cell through a mating bridge. This process can transfer plasmid DNA as well as chromosomal fragments, which is important for genetic mapping and diversity.
The actual number of bases in the F-plasmid that have been mapped may vary depending on the strain of E. coli, but it generally falls within the given size range. Plasmids are typically characterized and estimated in size through methods like gel electrophoresis. Furthermore, DNA supercoiling is a mechanism seen in bacterial cells like E. coli that allows the large genome to fit within the confines of the small cellular space.