Flashcards
Bacteria: Motility
Cards in this deck (12)
- 14 key parts of the flagellum?1. Filament
2. Hook
3. Basal body
4. Mot proteins - 2Name the key parts of the flagellum basal body.L ring anchored in OM
P ring anchored in peptidoglycan
MS and C rings anchored in CM
Rod connect MS ring and hook
Fli proteins - 3How is energy conserved in flagella?As a proton gradient
Outer surface = +ve as cell pumps H+ out of cell to create proton gradient
So H+ flows back into cell which generates energy to drive flagellum - 4How does the flagellum rotate?Mot proteins form ion-conducting complex
H+ move across CM through Mot complex
H+ bind to/dissociate from certain AAs in Mot proteins
Triggers conformational change of Mot protein
Drives rotation of basal body and rod - 5How do petrichious flagella work?Runs: CCW rotation of helical flagella bundle drives forward rotation (runs)
Tumbles: CW direction - filaments separate as flagella pushed apart - random movement around cell to reorientate
After tumble: return to CCW rotation and move in new direction - 6What determines the flagella rotation direction?Fli proteins determine if flagella rotate CW or CCW
- 7How do polar flagella work?1 end of cell
CCW rotation propels cell forward
Reversible - can rotate CCW and CW
Unidirectional - CW in initial direction--> reorientation --> CW in new direction - 8What happens in chemotaxis when an attractant is present?- Runs in favourable direction = longer
Tumbles = more frequent if cell starts to move in unfavourable direction
- Cell senses temporal gradient using MCPs in membrane
- Decreased phosphorylation of CheY (not phosphorylated)
- CheY can't bind to flagellar motor
- CCW rotation
- Runs towards favourable conditions - 9What happens in chemotaxis when a repellant is present?- Increase in phosphorylation of CheY in cytoplasm
- CheY-P interacts w/ flagellar motor
- Induces CW rotation
- Tumbles away from unfavourable conditions - 10What are fimbrae?Filamentous pili
Made of protein
G-ve and G+ve
Important in
- Adhesion
- Motility
- Pathogenicity - 11Describe the structure of the T4 pilus.- Adhesin at tip
- Filament made of pilin subunit
- Secretin in OM
- Platform in CM and periplasm
- 2x ATPases in cytoplasm - 12How does twitching motility work?- Pilus extended - subunits added to base of pilus to push out projection (extension ATPase)
- Adhesive tip adheres to surface
- Pilus retracts (subunits removed) - retraction ATPase
- Cell moves closer to site of adhesion
Information
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- Year 1 BIO172 - Microbiology Flashcards on Bacteria: Motility, created by Sophie Byrne on 20/05/2018.
- Created by
- Sophie Byrne · May 2018
- Updated
- May 20, 2018
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