Quiz 1 - Mulvey - Bacteria Basics Flashcards
What is the purpose of a bacterial cell wall?
Maintain cell shape, influx/efflux of materials, protect against osmotic lysis
*Target of lysozyme, antimicrobials, and antibiotics
What is the difference b/t Gram + and gram -?
(+) - Large peptidoglycan wall
-) - Thin peptidoglycan wall with an outer membrane of lipopolysaccharide (LPS
Bacterial cell walls are sites for what 3 main things?
Respiratory chains
Secretion (transport) systems
Adhesins
Cell walls allow for stereotyping pathogens. Tell me the three.
K (Capsule)
H (Flagellin)
O (LPS)
*KHO CFL
NAM and NAG is on what type of wall?
GRAM +
*Off the NAM is a peptide chain
Biosynthesis of gram + cell walls are inhibited by what type of antibiotics?
Beta-lactams like penicillin
Binding of LPS by the Pattern Recognition Receptor (PRR) Toll-like Receptor 4 (TLR4) can stimulate what?
Inflammatory responses
What bacteria don’t have a cell wall?
Ureaplasma and mycoplasma
What are 6 other factors associated with bacterial cell walls?
ETCs
Protein secretion systems
Flagella
Adhesins
Capsules
Spores
Autotroph
Phototroph
Chemoautotroph
Heterotroph
Chemoheterotroph
Fermentation
Make their own food
Use light for energy
Chemicals for energy
Use organic sources for energy
Humans. Get energy by consuming other organisms
Used by many bacteria to breakdown glucose to pyruvate, which creates ATP
Obligate aerobe
Obligate anaerobe
Facultative anaerobe
Microaerophile
Aerotolerant
Need O2
O2 is toxic
Do better with O2, but can grow w/o it
Need a little bit of O2, but too much is toxic
Not effected by presence of O2
T/F - Bacteria have mechanisms to send proteins out of their cells.
True
*Of note are Type III, IV, VI, VII can inject proteins or toxins directly into target host cells
Peritrichous
Monotrichous
Lophotrichous
Amphitrichous
All over
One, one end
Multiple, one end
Two, one on both sides
What are axial filaments?
Flagella present with the periplasmic space
*Like spirochetes
What are bacterial adhesins?
Allow the bacteria to attach to host cells (lipids, proteins, or sugars)
Consist of proteins with hair-like fibers called pili or fimbriae
What else can adhesins do?
Contact with other bacteria, ECM, biofilms, etc.
Unique receptors (Colonize in the gut, brain, urinary tract, etc.)
Anti-adhesins being developed as anti-bacterial therapeutics
Act as receptors for viral phages
T/F - Some bacteria can move by extending a pilus and retracting it.
True
What are capsules?
Layers of polysaccharide on the surface of bacteria
*Provides protection against desiccation, phage (virus), detergents, and antimicrobials. Also from phagocytes (neutrophils and macrophages)
What causes 26% of deaths worldwide?
Infectious diseases
What are the oldest, most prevalent forms of life on earth?
Bacteria
What is cocci?
Spherical
What is bacilli?
Rod shaped
What is spiral?
Comma or S-shaped, or spiral
What is pleomorphic?
Lacking a distinct shape
What are 7 unique features of bacteria?
- Singular chromosome
- May have plasmids
- No organelles, no nucleus
- Cell wall components
- 70S ribosomes
- Unique metabolic pathways
- Binary fission
*These features allow for the basis of recognition by innate and adaptive immunity and antibiotic therapies
Walk me thru binary fission. 3 steps.
DNA replication
Chromosome segregation
Cytokinesis
What is the lag phase?
The bacteria adapting to their environment
What is the log phase?
Exponential growth (binary fission)
What is the stationary phase?
Death = growth
What is the death phase?
Death
Bacteria are often associated with biofilms. Tell me their 4 step process.
Attachment
-Suppression of motility factors, induction of adhesion factors
Sessile
-Intercellular interaction, quorum sensing
Biofilm maturation
-Induced extracellular polysaccharides (matrix) synthesis
Dispersal
-Quorum sensing, induction of disassembly factors
Name three sites where biofilms can form.
Environment (air conditioning towers)
Medical devices (Catheters, valve implants, replacement joints)
Body surfaces (lungs of cystic fibrosis patients, burned tissue, wounds, gingiva and enamel [plaque])
