Bacteria Flashcards
Identify the main shapes of bacteria (morphology)
- Coccus, Bacillus
- Can range in size from visible by the human eye to X-ray crystallography
Strepto vs Staphyl
Chain vs Cluster
Gram +ve bacteria traits
- thick cell wall
- stains blue with gram stain
- no outer membrane, maybe s-layer
- thick peptidoglycan with a pentagly bridge between peptidoglycan
glycocyl chains
-teichoic acids between peptidoglycan
Glycocalyces
- do not confer significant structural strength
- poly saccharide layer
Capsules or Slime layer
Capsules
tightly attached, tight matrix, visible if treated with India ink, found in all bacteria
Slime layer
- loosely attached, easily deformed layer that assists in sticking to surfaces,
- plays a role in biofilm formation
- can act as a virulence factor cause it protects the bacteria from phagocytosis
- prevents dehydration/desiccation
S-layer
Protective layer found in FREE LIVING (not lab grown) gram +, - and archaea with a crystalline layer consisting of proteins or glycoproteins, may contribute to cell shape and help protect the cell from osmotic stress
Gram -ve Cell wall
- thin cell wall
- just a peptide crosslink between 2 peptidoglycan
-lipopolysaccharides
lipid A: endotoxin - lipoprotein from outer mb and peptidoglycan
lysozyme
can destroy peptidoglycan
enzymes cleace glycoside bond between sugars
found in human secretions major defence against infection
gram -ve traits
- thin cell wall
-stains pink - LPS
-lipoprotein
outermembrane
gram +ve cell wall
-thick cell wall
-peptidoglycan with pentagly bridge
peptideglycan + teichoic acids
teichoic acids
- glycopolymer
helps generate PMF
protects against salt and temp
protects against Abx
acid-fast
light blue with gram
inner mb, peptidoglycan, mycolic acid (hydrophobic)
What is targeted by Abx
biggest target cell wall (b-lactams, penicillin, vancomycin literally all the host girls)
FtsZ
tubulin like, spherical shape, forms ring participates in septation
MreB
actin like, spiral, elongation, rod
crescentin
filament like, curvature in crescents
Par system
segregates the dividing chromosome to the two polls
- a protein attaches to and recognizes genome
- ParM and actin like protein starts to polymerize pushing genome to opposite sides
nucleiod
region where the DNA is found
Genetic information storage and gene expression
ribosomes
made of RNA translation, protein synthesis
Inclusion bodies
storage or reservoir
endospores
dormant, protected versions of the bacteria, formed through sporulation kinda like a really intense hibernation come back when conditions are better, once you start you can’t really go back
Flagella
swim
long thin appendages
uses PMF and dictates the speed
attractants cause CCW rotation bundle and push forward –> run
repellent or absence of attractants cause CW no bundle so tumble
Fimbriae
help stick to surfaces or or form pellicles
Pili
typically longer very few
conjugative pili or type IV adhere to host tissues
types of locomotion
taxis response to them or physical gradients, swimming, gliding
unique to bacteria
- peptidoglycan, which is why it’s good target for Abx
- inclusion
-pili
penicillin
inhibits transpeptidase that cross-links the peptides
Vancomycin
prevents cross-bridge formation by binding to the terminal
cell division
regulated by DNA replication,
2 ORI sites and red forks in opposite directions, FtsZ firms ring septum forms
Polar bacterial cell differentiation
think of c. crescentus one pole is stalk others
