hi sam,
im raju
bacteria is an procariot (organisms with out an nuclear membrane)_ and paramitium is an eukariot(wit nuclear membrane)
hence when two bacterias make an conjugation bridge only a segment of the whole circula dna breaks and enters athe other
when paramisium conjugate there r two nucleus found one large & one small the small one enters the other organisms

usually all te water microbes are free swimmers and they while moving from one place to another they experience a constant density plane and a smooth plane hence their body is radial(cut there body into two at their radius they form two similar copies) and the organism in soil experience different land marks they need to cghange their body structures a lot eg: amoiba

if u have any further doubts u can inter act wit me on “sri18khan@yahoo.co.in” ur always welcome to ask any thing about biology .biology is not boaring its just that u dont understand it ,
ur friend
raju