Fimbriae And Pili Flashcards
What are fimbriae and pili?
They are hairlike appendages on many gram-negative bacteria, shorter, straighter, and thinner than flagella.
What protein are fimbriae and pili made of?
They are made of a protein called pilin arranged helically around a central core.
How do fimbriae and pili differ?
Fimbriae and pili have different functions; fimbriae are mainly for attachment, while pili are often involved in DNA transfer.
Where can fimbriae be found on a bacterial cell?
Fimbriae can occur at the poles of the cell or be evenly distributed over the entire surface.
How many fimbriae can a bacterial cell have?
A bacterial cell can have a few to several hundred fimbriae
What is the primary function of fimbriae?
Fimbriae help bacteria adhere to each other and to surfaces, which aids in biofilm formation and colonization.
How do fimbriae contribute to disease?
Fimbriae allow bacteria like Neisseria gonorrhoeae and E. coli O157 to adhere to host tissues, enabling colonization and infection.
What happens when bacteria lack fimbriae?
Without fimbriae, bacteria cannot adhere to surfaces or colonize, preventing disease formation.
What are pili?
Pili (singular: pilus) are hairlike structures on bacteria, usually longer than fimbriae, with only one or two per cell.
What functions are pili involved in?
Pili are involved in motility and DNA transfer.
What is twitching motility?
Twitching motility is a type of movement where a pilus extends, attaches to a surface, and then retracts, causing short, jerky movements.
Which bacteria exhibit twitching motility?
Pseudomonas aeruginosa, Neisseria gonorrhoeae, and some strains of E. coli.
What is the grappling hook model of twitching motility?
: It is the model where the pilus extends, attaches to a surface, and then retracts, pulling the bacterium in short, jerky motions.
What is gliding motility?
Gliding motility is a smooth movement, often observed in myxobacteria, allowing travel in environments with low water content.
How is gliding motility useful for bacteria?
It helps bacteria move through low-water environments, like biofilms and soil.
What are conjugation (sex) pili?
Conjugation pili are pili used to connect two bacterial cells for DNA transfer in a process called conjugation.
How does conjugation work?
An F+ cell uses a conjugation pilus to connect to another cell, transferring DNA, which may give the recipient new abilities like antibiotic resistance.
