"Build-a-Bacterial-Cell Workshop" Flashcards
BASE: What do you get with molecutes?
- DNA
- Rhibosomes
- Cytoplasm
- PM
BASE: Pros/cons of molecutes.
PROS:
- Cheap to maintain
- Small + compact
CONS:
- Not self-sustainable: usually requires eukaryotic host
- Complex diet: lacks organelles for enhanced metabolism
- Unattractive
BASE: What do you get with a G+ cell wall?
- DNA
- Rhibosomes
- Cytoplasm
- PM
- Thick + “fuzzy” cell wall (20-80 nm)
BASE: Pros/cons of G+ cell wall.
PROS:
- Strong: tectonic acid strands through peptidoglycan layers
- Resistant to osmotic lysis
- Diverse shapes (coccus, bacillus, spirilium)
CONS:
- Fatal in contact with lysozyme
- Sensitive to cell-wall targeting antibiotics (EX: penicillin)
BASE: What do you get with a G- cell wall?
- DNA
- Rhibosomes
- Cytoplasm
- PM
- Thin cell wall (1-2 peptidoglycan sheets)
- Lypopolysacchrides (OM)
BASE: Pros/cons of G- cell wall.
PROS:
- Capable to defend itself
- Built-in stage compartment (periplasmic space)
- Resistant to osmotic lysis
- Diverse shapes (coccus, bacillus, spirilium)
CONS:
- Toxic if mishandled
- Expensive to maintain: requires larger genome for cell wall complexity
What are cell walls made of?
Cell walls are composed of peptidoglycan.
What is peptidoglycan and what is it made of?
Peptidoglycan - Polymer of sugars and amino acids.
Made of:
- N-acetyl glucoseamine (NAG)
- N-acetyl muramic acid (NAM)
What is the structure of a lipopolysacchride?
TOP TO BOTTOM: 1. A-antigen 2. Outer core 3. Inner core 4, Lipid A
BASE: which bacterium are eligible to receive the “waxy” model?
Mycobacterium.
BASE: What makes the “waxy” model unique?
Includes mycotic acids that forms a thick, waxy surface that is very hydrophobic and chemically resistant.
BASE: Pros/cons of “waxy” model.
PROS: Resistance to the following:
- Osmotic lysis
- Detergents
- Dryness
- (Most) disinfectants
- (Most) antibiotics
- Oxidative burst
- Phagocytosis
CONS:
1. Slow-growing
ADDED EXTRAS: what is the s-layer?
S-layer - an additional protective layer of crystalline (glyco)protein subunits.
ADDED EXTRAS: what are the benefits of the s-layer?
Highly ordered: can flex and allow for molecular movement.
ADDED EXTRAS: what is the capsule/slime layer?
Capsule/slime layer - slippery coat of loosely-bound polysaccharides that prevents against phagocytosis and innate immune system activation.
ADDED EXTRAS: if the slime layer and s-layer exist on the same cell, where are they found?
S-layer: beneath.
Slime layer: to the outside of the s-layer.
ADDED EXTRAS: what are thylakoids?
Thykaloids - specialised folded laminae sheets of membranes filled with photosynthetic proteins and electron carriers that maximises its photosynthetic ability.
ADDED EXTRAS: which cells can have thylakoids?
G- cells.
ADDED EXTRAS: what are carboxysomes?
Carboxysomes - polyhedral structures that contain enzymes used to fix CO2.
ADDED EXTRAS: which cells can have carboxysomes?
All cyanobacteria and CO2-fixing G- cells.
ADDED EXTRAS: what are storage granules?
Storage granules - compartments that allow bacteria to store excess nutrients for consumption when availability is low.
ADDED EXTRAS: how are nutrients stored within storage granules?
- Glycogen
- Polyhydroxybutyrate (PHB)
- Poly-3-hydroxyalkanoate (PHA)
ADDED EXTRAS: what are magnetosomes?
Magnetosomes - membrane-bound magnetite (Fe3O4) crystals that allows motile bacterium to orient itself with the Earth’s magnetic field (magnetotaxis).
ADDED EXTRAS: which cells can have magnetosomes?
G- aquatic cells.
ADDED EXTRAS: what are phili used for?
Phili - used for bacterial adhesion, bacterial sex (conjunction), and movement as grappling hooks (twitching motility).
ADDED EXTRAS: what characteristics do phili have?
- Various lengths
- Flexible or brittle
- Curly or straight
- Singular or twisted in rope-like bundles
ADDED EXTRAS: what are stalks?
Stalks - membrane-embedded cytoplasmic extension.
ADDED EXTRAS: what are stalks used for?
- Secreting factors (holdflasks)
- Antenna for nutrient location
- Anchor for bacterium location
ADDED EXTRAS: what are rotary flagella?
Rotary flagella - long and rigid helical proteins that allow bacterial motility via chemoreceptor activity and PMF.
ADDED EXTRAS: which cells can have stalks?
G- cells.
ADDED EXTRAS: where are rotary flagella located on G- and G+ cells?
G- : OM
G+: cellular membrane
ADDED EXTRAS: what are the possible flagella arrangements?
- Petrichlorous (all around)
- Lophotrichous (bundled on one side)
- Monotrichous (one flagella)
- Amphitrichous (one on either side - 2 in total)
ADDED EXTRAS: what is the movement mechanics of flagella?
Motor runs at 100% efficiency, flagella movement is propeller at 1000rpm.
ADDED EXTRAS: what are nanotubes?
Nanotubes - extensions of cellular envelope that allows transmission of compounds between cells.
ADDED EXTRAS: where are nanotubes located for G+ and G- bacteria?
G+: cytoplasm
G- : periplasm
ADDED EXTRAS: can nanotubes occur cross species, and who are most likely to use them?
They can occur cross-species, and biofilm-forming bacteria use them.