Comparison between Plasmid, BAC and cloning vector is given bellow :
Plasmid : A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently.
They are most commonly found as small circular, double-stranded DNA molecules in bacteria;
Plasmids are sometimes present in archaea and eukaryotic organisms.
BAC : A bacterial artificial chromosome is a DNA construct, based on a functional fertility plasmid, used for transforming and cloning in bacteria, usually E. coli.
These are a circular, bacterial F element-based plasmid containing an average of about 180–200 kb of genomic DNA.
They enable stable cloning of large DNA fragments from single genomes or microbial assemblages.
Cloning Vector : A cloning vector is a small piece of DNA that can be stably maintained in an organism, and into which a foreign DNA fragment can be inserted for cloning purposes
Cloning vector are useful for generating many copies of a gene.
Used as the vehicle for transporting foreign genetic material into another cell.