biofilms

Question 1

what is a biofilm

Answer 1

when bacteria attach to a surface and grow there

Question 2

what are exopolysaccharides

Answer 2

The matrix in which bacteria grow in a biofilm. 90% of the biofilm is made up of the EPS rather than the cells themselves

Question 3

what are the four stages in biofilm development

Answer 3

Attachment
Colonisation
development
active dispersal

Question 4

how do cells attach to a surface to form a biofilm

Answer 4

the bacteria collides with the surface by random chance. Surface structures on the bacteria, often flagella, stimulate adhesion.
Adhesion stimulates the activation of biofilm genes that synthesise the matrix that holds a biofilm together.
Once committed to a biofilm cells often lose their motility.

Question 5

why are biofilms advantageous

Answer 5

They can protect against predation by protists and small grazers
they can trap nutrients for microbial growth
they prevent bacteria from being washed into a less favourable habitat
Since horizontal gene transfer is happening all the time, bacteria are more resilient to antimicrobial agents

Question 6

what are microbial mats

Answer 6

huge biofilms often 5-10cm thick. They usually occur in extreme environments, either acidic or hot, due to the absence of predators

Question 7

what is dental plaque

Answer 7

dental plaque is a biofilm