PID BLOCK3- bacteriology Flashcards
Ribosomes
- ribonucleoproteins w large 50s and small 30s subunit
- protein synthesis + translation
-target for antibiotics
- 16s rRNA gene encoding for 30s subunit used for reconstructing phylogenies
Plasma membrane
inner membrane next to cytoplasm
-PHOSPHOLIPID BILAYER + PROTEINS
-where energy is stored
Proteins in the plasma membrane
- Transport proteins
- Energy generation components
- Proteins that anchor or help assemble
Transport proteins
- in the plasma membrane
-transport of specific molecules in and out of cell
- mediates passage of hydrophilic substances
Energy generating components
synthesis of ATP in plasma membrane
Phospholipid bilayer
Part of plasma membrane
-hydrophobic/hydrophilic sides
-Hydrophobic/ lipid solube can pass with passive diffusion
Main functions of plasma membrane
- Selective permeability barrier
- Bacterial respiration and energy generation
- Anchor for external structures
Cell wall
PEPTIDOGLYCAN LAYER
-mesh like structure containing alternating subunits of NAG and NAM cross-linked w peptides by transpeptidase enzymes called Penicillin binding proteins (PBPs)
Peptidoglycan
Bacteria cell wall, good target for antibiotics
polymer unique to prokaryotic cells
Penicillin- binding proteins
PBPs
- transpeptidase enzymes that connect with NAG and NAMs in cell wall
Function of cell wall
- Protection against mechanical damage and osmotic lysis
- Transport: non selective permeability
Outer membrane
- Only in Gram neg bacteria
Protein containing asymmetrical lipid bilayer (LIPOPOLYSACCHARIDE or endotoxin)
Function of outer membrane
Only in gram neg
- Selective permeability
- Resistance to large or hydrophobic toxic compounds
- Tolerance to detergents + bile salts
Lipopolysaccharides
- in the outer membrane of gram neg bacteria
-virulence factor
lipid A component = endotoxic activity
Mediator of septic shock
heat stable
Symptoms of LPS
- Fever
- Leukopenia
- Anorexia
- Diarrhea
- Blood coag
- Hemorrhagic shock
The exceptions to the 2 main structural classes of bacteria are?
Mycobacteria and Mollicutes (mycoplasma)
Mycobacteria
Bacterial envelope is gram + but contains MYCOLIC ACID
-Acid fast staining for identifying
Mollicutes (Mycoplasma)
Plasma membrane w sterols
NO CELL WALL- no peptidoglycan layer
Capsule
POLYSACCHARIDE LAYER
Function of the capsule
- Protection
- Virulence factors
- Nutrient reserve
Endospores
- Cryptobiotic state of dormancy, most durable
-Produced by Bacillus and Clostridium
-keratin spore coat helps survival
Function of endospores
- Ensure survival during adverse enviro conditions
- Dormant, highly resistant bodies
Flagella
-on bacterial surface
Flagella function
locomotion or bacterial motility
Pili/Fimbriae
- Fine, straight hair-like, attached to cell wall
- Most common on Gram neg bacteria
for adhesion
Function of pili/Fimbriae
- Adhesion to host tissues
- Contribute to antigenicity