(a) : Sex pili are minute and non-flagellar hairlike structures projecting from the wall of many gram negative bacteria and few Gram + ve ones. They are entirely composed of a protein called pilin. They are used as sex organs during conjugation, forms conjugation tube during conjugation. They confer the property of stickiness whereby bacteria tend to adhere to one another (clump formation). They are of two types-long conjugating pili and short attachment pili. Naked circular DNA is the genetic material which is not enclosed by nuclear membrane non complexed with proteins. It is called nucleoid or genophore. Plasmids (Hayes and Lederberg, 1952 ) are additional or extrachromosomal small rings of DNA having a few useful but nonvital genes, e.g., For fertility factor, R-factors or resistance factor.