Pili are very fine hair like appendages arises from cell membrane. Pili are made up of protein pilin. These are present in Gram-negative bacteria. During sexual reproduction in bacteria, pile of donar bacteria attached to recepient bacteria and forms a conjugation tube through which genetic material of donar go towards recepient bacterial cell.
Extra chromosomal genetic elements are known as plasmid. Flagella and cilia are organells for locomotion.