Growth Metabolism Flashcards
What is a nucleoid?
supercoiled, single chromosome
What is a plasmid?
genetic info that replicated independently of nucleoid
What is the only organelles in bacteria?
70s ribosomes
What is the cell wall of bacteria made of?
peptidoglycan
What is an endospore?
allows some bacteria to survive harsh conditions
What is a capsule?
anti-phagocytic
What is a pilli?
- attachment
- delivery of toxins
- exchange of genetic info
What are the cell shapes of bacteria?
- round -> coccus
- bacillus -> rod shaped
- spirochete -> cork-screw
What is lipopolysaccharide (LPS)?
- made of: repeating O Ag, core polysaccharide, lipid A
What has endotoxic effects that actovates inflammatory mediators?
lipid A -> can lead to septic shock
What are the 4 phases of bacterial growth?
- lag -> bacteria acclimate to new environment
- log -> exponential growth of bacteria
- stationary -> no significant net change in population
- death -> when population declines
What are the steps in gram staining?
- crystal violet -> stains everything purple
- gram iodine -> stabilizes purple color
- decolorizer -> alcohol or acetone; becomes colorless
- safranin red -> stains anything not stained red
What are the 4 types of bacteria?
- gram-positive rods & cocci
- gram negative rods & cocci
What are the characteristics of gram +?
- no outer membrane
- thick peptidoglycan
- no LPS
What are the characteristics of gram -?
- has outer membrane
- thin peptidoglycan
- outer membrane has LPS & porins
- large periplasmic space
What makes up a peptidoglycan?
- N-acetylmuramic acid & N-acetylglucosamine
- cross-linking holds sugars together via peptides from N-acetylmuramic acid
What causes 80% of UTIs?
europathogenic e. coli
What type of toxicity does bacteria show?
selective toxicity
What is bacteriostatic?
prevents growth but DOES NOT kill them
What is bacteriocidal?
kills bacteria
What is an example of a narrow spectrum of bacteria?
benzyl penicillin
What is an example of a broad spectrum of bacteria?
tertacycline
What is MIC?
minimum conc. of drug to stop growth of bacteria
What are peptidoglycan synthesis inhibitors?
- ex: penicillins & cephalosporins
- beta-lactam
- bind to penicillin binding protein
- leads to cell lysis (bacteriocidal)
What are nucleic acid synthesis inhibitors?
- bacteriocidal
- prevent DNA replication/transcription
- bactericidal
- ex: quinolones -> inhibit DNA gyrase & rifampin -> inhibit DNA-dependent RNA poly
What is the role of tetracyclines as a protein synthesis inhibitor?
- bacteriostatic
- prevent aminoacyl-tRNA from binding to 30S subunit
- fights against obligate intracellular bacteria
What is the role of amidoglycosides as a protein synthesis inhibitor?
- bactericidal
- causes misreading of mRNA
- binds to 30S subunit & prevents translocation
What is the role of macroslides as a protein synthesis inhibitor?
- bacteriostatic
- binds to 50S subunit
- used against legionellae & mycoplasma
- resistance through modifying rRNA
What inhibits steps in the folic acid biosynthesis pathway?
trimethoprim & sulfanilamide
What are the characteristics of folic acid synthesis inhibitors?
- bacteriostatic
- resistance through decreased permeability (T) or target modification (S)
- ex: trimethoprim & sulfanilamides
