Chapter 7 The Control of Microbial Growth

Question 1

What does sepsis refer to?

Answer 1

refers to bacterial contamination

Question 2

what does asepsis refer to?

Answer 2

the absence of significant contamination

Question 3

what does it mean when there is a sterilization technique being used?

Answer 3

removes and destroys ALL microbial life

Question 4

what does it mean when there is a commercial sterilization technique being used?

Answer 4

specifically aimed at killing Clostridium Botulinum endospores in canned goods which can cause botulism

Question 5

what does it mean when there is a disinfection technique being used?

Answer 5

destroys HARMFUL microbes

Question 6

what does it mean when there is an antiseptic technique being used?

Answer 6

destroys HARMFUL microbes from LIVING TISSUE

Question 7

what does it mean when there is a degerming technique being used?

Answer 7

mechanical removal of microbes from a limited area
(such as using an alcohol wipe on skin before injecting a needle)

Question 8

what does it mean when there is a sanitization technique being used?

Answer 8

lowers microbial counts to safe levels on eating utensils

Question 9

what makes sterilization different from the rest of the cleaning techniques?

Answer 9

sterilization removes and kills ALL microbes

Question 10

what is the distinction of antisepsis technique?

Answer 10

destroys harmful microbes from LIVING tissue

Question 11

In what way do we chart the microbial death curve? what does this result in?

Answer 11

logarithmically; results in a straight line

Question 12

why would the microbial death curve be a straight line?

Answer 12

because bacteria usually die at a constant rate

Question 13

what are the four factors that affect the control of the microbial death rate?

Answer 13

time of exposure
type of microbe
number of microbes
environmental factors (temp/pH/O2/organic material)

Question 14

on the scale that shows the relative susceptibility of different microbes which microbes are most resistant?

Answer 14

prions

Question 15

on the scale that shows the relative susceptibility of different microbes which microbes are least resistant?

Answer 15

viruses with lipid envelopes

Question 16

are gram positive or gram negative bacteria most/least resistant?

Answer 16

gram positive - less resistant
gram negative - more resistant

Question 17

what is another name for a biocide?

Answer 17

germicide

Question 18

what is a germicide?

Answer 18

treatment that kill microbes (like a specific type of microbe)

Question 19

bonus question what is the bacteria that causes botulism?

Answer 19

Clostridium botulinum (endospores)

Question 20

what kind of microbial control technique involves the application of an alcohol swab before injection

Answer 20

degerming

Question 21

what is a fungicide an example of? what is it used for?

Answer 21

ex of biocide (germicide)
used to kill fungi

Question 22

does the presence of organic material affect most antimicrobial treatments?

Answer 22

The presence of organic matter often INHIBITS the action of chemical antimicrobials

Question 23

How does heat affect microbes?

Answer 23

kill microbes by denaturing their enzymes

Question 24

what are the two types of heat that can kill microbes?

Answer 24

dry heat
moist heat

Question 25

what causes the death of microbes in dry heat technique?

Answer 25

kills by oxidation effects

Question 26

what microbial control is the use of dry heat and moist heat?

Answer 26

sterilization technique

Question 27

what two ways can you perform dry heat?

Answer 27

direct flaming hot air sterilization

Question 28

which of the two DRY heat techniques takes longer? how does it work?

Answer 28

hot air sterilization items are placed into oven at 170 for 2 hours

Question 29

what are two examples of moist heat?

Answer 29

free-flowing system (autoclave) boiling (pasteurization)

Question 30

what causes the death of microbes in moist heat technique?

Answer 30

coagulates/denatures microbial enzymes

Question 31

which of the two types of heat takes the longest to kill microbes?

Answer 31

dry heat

Question 32

which type of heat is most effective at killing microbes? why?

Answer 32

Autoclave high specific heat of water causes the moist heat to be transferred into cells (good at killing endospores this way)

Question 33

what are the standard conditions for autoclave to ensure sterilization?

Answer 33

121 Celsius at 15 psi for 15 minutes

Question 34

how does filtration act to sterilize solutions?

Answer 34

Mechanically separates microbes from substances by filtering through a screen-like material different screen materials can trap different sized microbes

Question 35

what two things are not effectively removed by filtration?

Answer 35

flexible bacteria (spirochetes) wall-less mycoplasma

Question 36

what are two types of filters that can be used?

Answer 36

HEPA filters (bigger particles) membrane filters (smaller)

Question 37

how does refrigeration work? does it kill microbes?

Answer 37

slows enzymes/ does not kill (bacteriostasis)

Question 38

how does fast freezing (deep freezing) work? does it kill microbes?

Answer 38

mostly slows enzymes/ does not kill (bacteriostasis)

Question 39

how does slow freezing work? does it kill microbes?

Answer 39

kills microbes any water within bacteria will become crystals which disrupt cellular and molecular structure

Question 40

Radiation causes damage to which cellular macromolecule?

Answer 40

DNA (nucleic acids)

Question 41

what are two examples of ionizing radiation used to kill microbes?

Answer 41

X-rays gamma rays electron beams (used in post office)

Question 42

how does ionizing radiation cause microbial death?

Answer 42

creates hydroxyl radicals which causes lethal mutations in DNA

Question 43

how does nonionizing radiation cause microbial death?

Answer 43

damages DNA by creating thymine dimers which inhibit DNA replication

Question 44

what is an example of nonionizing radiation?

Answer 44

ultraviolet

Question 45

is microwaving an effective control of microbial growth?

Answer 45

no, it's not really great at killing microbes

Question 46

what is plasmolysis?

Answer 46

occurs from bacteria being put into a hypertonic solution causing water to leave out of the cell and ruptures the cell wall

Question 47

what is the mode of action of alcohols?

Answer 47

usually denatures proteins

Question 48

what microbes does alcohol work best on? not best on?

Answer 48

bacteria and fungi not endospores and nonenveloped viruses

Question 49

what are some examples of alcohols that can be used to kill microbes?

Answer 49

ethanol isopropanol Purell GermX

Question 50

what type of microbial control do alcohols offer?

Answer 50

degerming (best used on surfaces)

Question 51

mode of action for phenols?

Answer 51

injures lipids of plasma membranes causing leaky cells

Question 52

what is the chemical used in Lysol to give it its disinfecting properties?

Answer 52

cresols (phenols)

Question 53

mode of action of biguanides?

Answer 53

disrupt plasma membranes (esp. gram-positive bacteria)

Question 54

mode of action of halogens?

Answer 54

impairs protein synthesis and alters cell membranes

Question 55

what is the example of biguanide?

Answer 55

in surgical hand scrubs (mouthwash?)

Question 56

what are examples of some halogens?

Answer 56

iodine betadine chlorine

Question 57

what is the oldest and most effective chemical control agent?

Answer 57

iodine

Question 58

mode of action of chlorine?

Answer 58

Inhibits cellular enzyme system

Question 59

how do surfactants act to rid the body of microbes?

Answer 59

it attaches to pieces of dirt(microbes) and lift them off the surface, making them then able to be washed away

Question 60

mode of action of heavy metals?

Answer 60

denature proteins

Question 61

what are examples of heavy metals that KILL microbes?

Answer 61

silver copper zinc

Question 62

what are two examples of oxidizing agents used to kill microbes?

Answer 62

peracetic acid benzyl peroxide

Question 63

what are two examples of aldehydes used to kill microbes?

Answer 63

formalin glutaraldehyde

Question 64

which chemicals act as sterilants?

Answer 64

peracetic acid glutaraldehyde

Question 65

*written question* what are the 4 factors that effect microbial death rate?

Answer 65

time of exposure type of microbe number of microbes environmental factors (temp/pH/O2/organic material)

Question 66

*wq* what are three parts of the cell that various control agents target/ kill/ inhibit in microbes?

Answer 66

plasma membrane (lysing cell) proteins (enzymes) nucleic acids (DNA/RNA)

Question 67

*wq* how do surfactants act to rid the body of microbes?

Answer 67

(degerming agent) Surfactants act as an emulsifier that reduces surface tension between liquids, breaking apart any oily film into tiny drops with microbes attached, then being able to be rinsed/scrubbed off