More complex transposons have other genes between two insertion sequences. These complex transposons often carry genes that make the bacteria resistant to antibiotics. The movement of a transposon is catalyzed by the tranposase enzyme. Transposase recognizes the inverted repeats belonging to insertion sequences. The inverted repeats in the insertion sequences and the target sequences are not homologous sequences.
Transposons can move between chromosomes, between plasmids, and between plasmid and chromosome.
If a transposon is inserted into a gene, it effectively mutates that gene.