Appendages and Internal Structure Flashcards
What are the function of capsules and slime layers?
Attach to surfaces
Protect from phagocytosis
Capsule vs Slime layer
Capsule more well-organized, pressed against the cell, and protects better against phagocytosis
Slime layer are not closely attached to the cell, they are used to form biofilms
What can block capsule development?
Cyclic polysaccharide
What is flagella made up of?
Filament, hook, shaft, and basal body
What is basal body made up of?
Bushing (reduces friction)
Stator (generates torque)
Rotor (does rotation)
How is flagellum built?
Flagellin is exported from the cytoplasm through a type III protein export apparatus
How does flagellum move?
PTM; H+ move through stator. Torque is transmitted to the rotor.
What is chemotaxis?
Descriptor for flagellum movement. Bacteria move towards chemoattractants
What is “run” mode?
C-ring has counterclockwise rotation, bacteria move in one direction
What is “tumble” mode?
C-ring has clockwise rotation, flagellum move in different direction, bacteria “tumbles”
What structure is the C-ring part of?
Stator
Function of pili
Attachment to surfaces
Motility
Electron transfer between cells
Methods of motility using pili
Gliding
Twitching
What are nanowires?
thin, long tubular extension of cell membrane that extends from one cell to another that allows sharing of nutrients and electrons
What do bacteria use for storage? What do they store?
Granules can store carbon, phosphate, or sulfur
What form is carbon stored in bacteria?
glycogen granules, PHB, or PHA granules
What form is phosphate stored?
Volutin, acts as energy storage
What can microcompartments store?
- Enzymes
- Pigments for photosynthesis
- Gas
- Magnetite
What pigments are used for photosynthesis?
phycobilisomes and chlorosomes
What is magnetite? How is it stored?
iron compound stored in magnetosomes
What are carboxysomes?
carbon fixation by RuBisCo
What are endospores?
Metabolically inactive cells that are highly resistant to damage
What causes formation of endospore? When does it germinate?
Forms during starvation, germinates in response to nutrient availability
Can any bacteria form a spore?
No, only a few genera can
Describe process to form a spore
Stage 0: normal growth
Stage 1: bacterial division (duplicate DNA)
Stage 2: Asymmetric septation (split the cell)
Stage 3: Engulfment (larger cell surrounds spore)
Stage 4: Cortex Synthesis (around spore)
Stage 5: Coat Synthesis (around spore)
Stage 6: Lysis of mother cell (larger cell lyse, leaving spore)
Stage 7: Free spore
Describe the core of an endospore
DNA is tightly compacted around SASP which makes it UV resistant.
DIpicolinic acid draws water away making it heat resistant
Describe the cortex of an endospore?
made up of special peptidoglycan which are loose and expansible
