L9 Microbial Interactions, Signalling and Specialised Metabolism Flashcards
What is a biofilm
A community of microbes attached to a surface
What is chemotaxis
Cell movement along a gradient sensing favourable conditions
Explain how bacteria sense a gradient and move towards an attratctant
Periods of flagellum movement counterclockwise towards attractant and the clockwise motion to stop forward motion
Period of tumbling to assess gradient
Why is it beneficial to be a biofilm
Harder to be consumed or attacked
What can affect biofilm formation
Nutrition needs to be plentiful
Physical conditions (pH, iron conc, temp, oxygen)
Co-colinisation
Do interconnections of the periplasm have to be in one species
No, different species can form interconnections with one another e.g. Horizontal gene transfer, share of mRNA
What is intercellular SENSING
Information gained from environment
Physical conditions, change vaused by other organisms
What is intercellular SIGNALLING
Signalling between cells via small organic compounts
Taken up by cell and cause change, involve specific signalling pathways and gene expression
Is Quorum sensing a sensing or signalling prcess
Signalling
What is Quorum sensing
Secretion of small molecules within a bacterial population which cause a coordinated behaviour when a threshold (quorum) is reached
When dental plaque is removed, why does the same composition of species return
Chemical interdependence formed during sugar metabolism
Can the metabolites of one species impact others
Yes
What impacts can secondary / specialist metabolites have on another species
Phenotypic or intracellular
What are actinomycetes
High GC content, gram positice soil inhabitants
What causes the earthy smell when it rains
Actimomycetes rekeases volatile geosmin from dead cells
