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Flashcards in 5: Killing Bacteria Deck (66):
1

Fecal matter

80% bacteria
mostly gram positives anaerobesf found in intestine (most not disease causing)

2

colon bacteria

uncultureable outside of human gut

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firmicutes and bacteriodetes

2 main groups of bacteria in fecal matter

4

Germ free mice...

no bacteria in gut
hard to gain weight
lose lots of fluids

5

gut bacteria are good

provide vitamins and nutrients
do some metabolism
increase surface area of gut

6

fecal matter: what do we smell?

bacterial byproducts
negative association because eating it can kill us/make us sick

7

Waste treatment

remove-->isolate-->sediment-->purify

8

chlorine treatment of water

kills most bacteria

9

waste water treatment limitations

does not remove chemicals
like prozac, progesterone, antibiotics in water

no limitations on how much of these can be in water

10

the further you are from a water system...

the more chemicals that aren't broken down there are in your water

11

look at slide 4

look at slide 4

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Ways to kill bacteria

oxidation/reduction
membrane disruption
protein folding disruption

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Sepsis

microbial contamination

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Asepsis

absence of significant contamination

aseptic surgery techniques to prevent microbial contamination of wounds

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sanitization

lower microbial counts on eating utensils/in water to drink again

16

Biocide/germicide

KILLs microbes

17

Bacteriostaisis

inhibiting, not killing microbes

used in food prep to prevent foods from growing bacteria w/o removing the bacteria

18

sterilization

removing ALL microbial life

19

commercial steriliztion

killing C. botlulinim endospires... think restaurant cleaning

20

Disinfection

Removing pathogens
bleach
can also kill us

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antisepsis

removing pathogens from LIVING tissues (don't harm living tissue)

iodine

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disinfection vs. antisepsis

a choice... do we kill the host in order to kill all the bacteria?

23

Oxidation/Reduction

can mutate DNA
prevent/alter action of enzymes

24

Membrane Disruption

loss of proton motive force
loss of integrity

25

Protein folding disruption

temp and some chem change lowest nrg state of protein

causes misfolding or unfolding

26

Physical control of microbes

moist heat
dry heat

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moist heat

autoclaving
common for food
high temp WITH moisture

28

how moist heat works

high temp disrupts breaks hydrogen bonds in proteins

cool back down: proteins refold in a non-functioning way

think eggs... denaturation and rearrangement of proteins

29

autoclave

121C for 30 minutes
steam under a great among of pressure
moist heat
used by hospitals, dentists, good tattoo parlors, labs, disposal of bio waste

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autoclave is used to

STERILIZE things

will kill things that grow at room temperature

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why use pressure in an autoclave

to keep liquids from boiling so we can sterlize them

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Dry Heat

stimulates oxidation rxn
no moisture
covalent change... IRREVERSIBLE

oxygen overcomes potential nrg needed to react with chemicals.
heat allows it to stay spontaneous

33

where is human fecal matter

all over bodies... we're constantly leaking

important to clean underwear

34

underwear

front line to controlling fecal bacteria

we don't actually clean them well

35

examples of dry heat

burnt toast
bunsen burner
oven (cooks food by dry heat)

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dry vs. moist heat

moist: proteins come back together
dry heat: irreversible

37

burtn toast

oxygen reacted with carbon molecs

produced CO2 and carbon compounds that are the black burnt part

38

dry heat and underwear?

ineffective

39

Pasteurization

71C for 15 sec
heat very briefly: don't change it, just enough proteins are denatured (not all)

only kill PATHOGENIC bacteria
pathogen free, not sterile

40

autoclaving underwear

better than burning... stays the same but is sterilized

41

Examples of pasteurization

milk
beer
canned foods...heat long enough to kill spores to prevent spoilage

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Napolean

won at life because he could can food and take it with him and it didn't spoil

43

Pastureizing... what do we kill

we kill pathogenic bacteria and denaturizes SOME proteins

44

Filter Sterilization

non lethal removal of microbes
size exclusion...
pore size smaller than microbe

45

HEPA

High Efficiency Particulate Air Filter

huge filter than purrifies air

fume hoods
idea behind vacuums that remove microbes from air...eh

46

pastuerizing underwear

what we do if we wash in hot water and then dry... but not the most effective

47

filtering and underwear

not effective

48

advantages of filters

allows low temp removal of bacteria and viruses

keep proteins/enzymes functioning

MGD... cold filtered bevrages... doesn't change taste

49

how filtering works

pass liquid through filter with holes smaller than your microbe

50

cons of filtering

viruses and clamydia are usually small enough to get through

51

Desiccation

remove all water
prevents microbial growth but does NOT kill
freeze drying food... good for preservation

52

downsides to desiccation

many spores are resistant to it
some viruses are very resistant to it

does not kill bacteria in any way... just inhibits

53

Dessication and underwear

we also do this... dryer (dessication) to drawer (storage)

54

when and why is dessication useful?

preserving things (freeze drying)

55

Radiation

electromagnetic nrg
ionizing radiation
non-ionizing radiation

56

ionizing radiation

Gamma Rays
X rays
high nrg electrons

short wavelenght, high nrg

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non-ionizing radiation

UV light
sponge in the sun

shortish wavelengths, highish nrg

58

microwaves

heat water molecules

photons excite water molecules

long wavelenght, low nrg

59

radiation depends on wavelength

wide spectrum

long wavelength: lower nrg

60

radiowaves

don't kill anything
long wavelenght, lowest nrg

61

Infrared...

can kill bacteria... but not the best at it

62

UV light

causes damage to DNA

63

X-rays and Gamma Rays

do most of the sterilization
high nrg waves

as rays go through cell... they cause oxygen to react with protein and DNA of cell
protein becomes inactive
DNA is mutated

64

Underwear in the sun

leave it out for a long time inside out... really good way to sterilize

(used to do with clothes lines)

65

What is the best way to prevent foodborne illnesses

irradiation

kills EVERYTHING and still tastes the same

but no one will buy that food because people think its bad

(its not bad... it doesnt make the food radioactive)

66

irradiation

expose the thing to electormagnetic waves

place food near radioactive thing, doesnt make food radioactive, just kills all the microbes

microwaving