Intro to Bacteria II (lec 2) Flashcards
Flagella are?
purpose?
filament protein structure anchored to cell memb
motility (chemo-, photo-, aero- stimulated)
Flagella are source of what antigen
H antigen
Polar vs Peritrichous Flagella?
polar = on one or both ends
peritrichous = covers cell
Fimbriae/Pili are?
purpose?
arranged?
hair-like protein structures
promote adherence
pili = conjugation
peritrichously
Ribosomes structure?
bacteria = 70S (30S + 50S)
eukaryotes (fungi) = 80S (40S + 60S)
What antibiotics target 70S?
aminoglycosides (genta-, streptomycin)
macrolides (azithro, erythro)
Nucleoid (no membrane) contains?
allows for?
DNA, RNA, proteins
coupled transcription/translation (faster protein synth, faster response to environment)
Endospores produced by what kind of bacteria?
G+
endospore = cell in dormant stage
Endospores resist? (4)
desiccation
heat
disinfectants
acids
Protective elements of endospores? (2)
keratin coat
internal dipicolinic acid
What 2 G+ pathogens produce spores?
bacillus anthracis
clostridium tetani
Binary Fission is?
asexual reproduction
cell splits into daughter cells
4 phases of Growth Curve?
1) lag phase (metabolically active, not dividing)
2) LOG phase (rapid division at constant rate)
3) stationary phase (division rate = death rate, # of live cells constant)
4) death phase (no nutrient, high waste products)
Optimal pH for:
acidophiles
neutrophiles
alkaliphiles
acidophiles = < 5.4
neutrophiles = 5.4 - 8.5
alkaliphiles = > 8.5
Optimal temp for:
psychrophiles
mesophiles
thermophiles
psychrophiles = 15 -20 ºC
mesophiles = 25 - 40
thermophiles = 50 - 60
Obligate means?
physically and biochemically limited to one environment
Facultative means?
physically and biochemically adaptable to different environments
Example to Obligate Aerobe?
m. tuberculosis
Example of Obligate Anaerobe?
c. botulinum
Enzymes necessary for Aerobes to convert ROS?
SOD (Δs superoxides to H2 and H2O2)
Peroxidase/Catalase (Δs H2O2 to H2O and O2)
Facultative Anaerobes prefer?
aerobic metabolism
Facultative Anaerobes use what for metabolism in anaerobic conditions?
fermentation
e.g. e. coli, bacillus
2 types of pathogenic fermentation?
1) lactic acid (cavities)
2) H2 gas (gangrene)
Microaerophiles O2 requirement?
best in low [O2],
many are capnophiles (CO2 lovers)
e.g. t. pallidum, s. pneumo, n. gonorr
Aerotolerant Anaerobes O2 requirement?
survive in O2,
don’t use O2 for metabolism
e.g. l. acidophilus
What osmotic environment is lethal to bacteria?
hypertonic solutions
Halophiles environments?
high salt
e.g. (facultative) v. cholera, s. aureus
Bacterial DNA characteristics?
dsDNA
CCC (circle)
Supercoiled
Plasmid is?
extrachromosomal DNA
not necess for survival
code for resistance, toxins
replicate autonomously
Transformation is?
uptake of naked DNA from environment (product of lysed cell)
DNA recombines w/ chromo DNA is receiving cell
-> new gene expressed
Conjugation is?
one-way, direct contact transfer of DNA:
larger pieces
Type IV system (slide 8)
G+ thru pheromone
G- thru pilus
Transduction is?
chromosomal DNA transfer by bacteriophage (virus)
Generalized Transduction uses what cycle?
Lytic Cycle: (slide 45)
bacterial DNA packed into capsid = defective phage
defective phase injects new bacteria w/ DNA
Specialized Transduction uses what cycle?
Lysogenic Cycle:
phage injects viral DNA -> vDNA inserts into bacterial chromo (lysogeny) -> new DNA (prophage) make bacteria pathogenic
e.g. c. diptheriae, v. cholera
What are Transponsons?
mobile genetic element,
inserts into bacterial chromo/plasmid,
responsible for most resistant genes
Inclusion bodies are?
glycogen storage or structural blocks (sulfur, polyphosphates)
