Microbio Test 2 Flashcards
Glycogen
Polymer of glucose
Polyphosphate
A storage unit that saves phosphate for a bacteria.
Carbon storage polymers
-PHB
-PHA
Glycogen
Nutrient storage units of bacteria
-Carbon storage polymers
-Polyphosphate
-Elemental Sulfur
Structures that control location of bacteria
-Magnetosomes
-Gas vesicles
Magnetosomes
Help move the bacteria along the magnetic poles.
Gas vesicles
Provides buoyancy for phototrophs
Endospores
-Resistant to heat, harsh chemicals, and radiation
-Enable the survival during unfavorable conditions
-Dormant stage of life, no metabolic activity
-Mostly in Gram (+)
Anatomy of a endospore
-Exosporium
-Spore coat
-Core wall
-Cortex
-DNA
S-layers
-Paracrystalline
-Can be a cell wall and extra layer for Archaea
-Only can be extra layer for bacteria
Glycocalyx
-Made of polysaccharides
-Capsule is tightly adherent
-Slime layer is loosely adherent
Three functions of glycocalyx
-Adhesion to a surface or other cells
-> BIOFILM
-Prevent dissociation
-Avoid phagocytosis
Cell surface apendages
-Protein structures
-Fimbriae
-Pili
Flagella
Fimbriae
-Abundant
-Shorter
-Role in adherence
Pili
-Fewer per cell
-Longer
-Retractable
-Type 4 -> Motility
-Adherence
-Conjugation (exchange of DNA) horizontal gene transfer
3 parts of flagella
-Basal body
-Hook
-Filament
Flagella synthesis
-Grows at the tip
-Many gene products involved
Flagella arrangements
-Peritrichous (everywhere)
-Polar (one out the end)
-lophotrichous (multiple out of the end)
-Amphitrichous (multiple out of both ends)
Archaella (Archaea’s form of flagella)
-Grows from the base like pili
-Energy source is ATP
Bacterial gliding motility
-surface motility
-no obvious cell surface appendages
-caterpillar tractor
-Slime extrusion
Chemotaxis
Moves in response to chemical signals
Random walk
Swims and tumbles during swimming motility (not efficient)
Biased random walk
Swims for a longer time in the correct direction and then tumbles (more efficient)
Phototaxis
Movement towards light
Aerotaxis
Movement towards oxygen
Osmotaxis
Ionic strength
Hydrotaxis
Movement towards water
Binary Fission
Symmetric cell division in bacteria and archaea
Petroff-Hausser Counting Chamber
Pros:
-Very fast
Cons:
-Can’t distinguish live vs. dead cells
-Viewing motile cells is hard
-Doesn’t work at low cell densities
-Need a microscope
-liquid culture
Serial Dilutions
Pros:
-Counting live
-Will work with a high number of cells
Cons:
-Slow cells have to grow
-Cell clump
- “Great plate anomaly”
Viable Count
(Plate cells, agar-based medium)
Spread plate method;
-Grown on agar
Pour plate method:
-Mixed with agar
Spectrophotometer
Pros:
-Fast
-Observe growth phases
Cons:
-Can’t tell live vs. dead
-Doesn’t work well at high cell density
Growth Phases in BATCH Cultures
-Lag
-Exponential
-Stationary
-Death
Define or minimal medium
-All components are precisely known
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Psychrophile
-Cold Adaptations
-Alter protein structure, increased alpha helices creates more flexibility at colder temps
-Membrane structure is unsaturated fatty acids to create more fluidity
Mesophile
-Grows at room temp or body temp
Thermophile
-Live in hot conditions
