Pili and fimbriae are cell surface appendages present in bacteria other than flagella. These structures are not for locomotion.
Pili and fimbriae are surface appendages for attachment.

Pili
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Fimbriae
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Long, thicker, tubular structures
made up of protein pilin
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Thin and shorter than the pili
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Pili are found only in Gram
negative bacteria
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Fimbriae are found both in Gram
negative and Gram positive bacteria
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The number of pili are less (3-5
per cell)
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The number of fimbriae is 300-400
per cell
|
Formation of pili is governed by
plasmid genes
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Formation of fimbriae is governed
by bacterial genes in the nucleoid region
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Pili, involved in cell to cell
attachment during bacterial conjugation. Therefore
called as sex-pili
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Fimbriae is involved in cell to
surface attachment of bacteria
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