chpt 8
semiconservation dna
"The products that we get out always have one old strand paired with one new strand."
sterilization vs disinfection
sterilization: highest possible way to kill all microbes including endospores
disinfection: reduce/eliminate microbes from objects
antibiotic
derived from bacteria or fungi to targets bacteria and not the host
establish disease
1. entry portal
2. adhere
3. survive host defenses
4. causing disease
5. exit portal
conjuation, transduction, transformation
conjugation: uses pili for gene transfer
transduction: uses bacteriophage to inject another bacteria and drops off host dna
transformation: uses free floating dna around
dna polymerase vs rna polymerase
dna: makes more dna
rna: copies dna into rna
sanitation/decontamination
antisepsis/de-germination
1. reduce mircobes at safe levels
2. reduce microbes on living tissue
antibiotics-
broad vs narrow
broad: effective against variety of microbes grma -/+
narrow: limited group of microbes, target specific groups of bacteria
steps of infection
1. incubation
2. prodromal
3. acute
4. convalescence
5. continuation
mutation?
types: frameshift, nonsense, missense, silent
frameshift: deletion or addition of one base
nonsense: stop codon
missense: changes amino acid
silent: no change to amino acids
translation vs transcription
translation: mRNA into proteins
transcription: makes dna into rna (mRna, tRna, rRna)
hardest to kill vs easiest to kill
hardest: endospores, prions, non-eveloped viruses
easiest: enveloped viruses, bacteria/fungi, gram +
therapeutic index (TI); toxic dose/therapeutic dose
TI: safety margin of a drug
low TI: risky bad
high TI: good
mutualism
antagonism
commensalism
1. both host and microbes benefit
2. good microbes suppress pathogens
3. one benefits, other is neutral
spontaneous vs induced
spontaneous mutation: random/accident
induced mutation: caused by mutagens/ physcial or chemical agents disrupt dna
what is an operon? what parts does it contain?
operon is a group of genes working together as one
parts: 1. promoter- rna polymerse binds here
2. operator- regulator switch
3. genes: code enzymes
-cide/-cidal
-static
1. kill
2. inhibit growth
susceptibility testing:
selective toxicity:
1. sensitivity of pathogen to drugs
2. drug toxic to microbe and not host
opportunistic vs true pathogens
opp: microbe that is in us already thats good but can become pathogen
true: always causes disease in healthy person
thermal death time vs thermal death point
mode of action?
time: shortest time to kill microbes at specific temp
point: lowest temp to kill microbes in 10 min
mode of action: determines whether agent kills or inhibits growth
inducible vs repressible
inducible: always off, catabolic
repressible: always on, anabolic
target five
1. cell wall
2. cytoplasmic membrane
3. nucleic acids
4. synthesis of proteins
5. metabolic pathways
Minimum Inhibitory Concentration
antibiotic resistance
1. lowest concentration that visibly inhibits growth
2. resistance gained from horizontal gene transfer; bacteria evolves to survive exposure to antibiotics
endogenous vs exogenous
endo: inside body, come from same human host
exo: outside body, come from external environment
exotoxins vs endotoxins
exo: chemicals made by microbes release ENZYMES PROTEINS, i can use antibodies to help protect me
endo: lipopolysaccharide lysis release systemically can cause damage , all gram - bacteria, no antibodies