chapter 7: control of microbial growth

Question 1

sepsis

Answer 1

bacterial contamination

Question 2

asepsis

Answer 2

absence of significant contamination; Ex) aseptic surgery technique

Question 3

sterilization

Answer 3

removing and destroying all microbial life

Question 4

commercial sterilization

Answer 4

killing clostridium botulinum (botulism) endospores from canned goods

Question 5

disinfection

Answer 5

destroying harmful microorganisms

Question 6

antisepsis

Answer 6

destroying harmful microorganisms from living tissue

Question 7

degerm

Answer 7

removal of microbes from a limited area

Question 8

sanitization

Answer 8

lowering microbial counts to safe levels

Question 9

biocide / germicide

Answer 9

treatments that kill microbes

Question 10

bacteriostasis

Answer 10

inhibiting, not killing, microbes

Question 11

what are the effects of damaging the plasma membrane?

Answer 11

disrupting / damaging the cell

Question 12

how can proteins be damaged and what are the effects?

Answer 12

cross-linking and denaturing damages proteins; impedes enzyme function and halts biological activity

Question 13

what are the effects of damage to nucleic acids?

Answer 13

possible permanent mutation caused by damage beyond DNA repair capability

Question 14

dry heat sterilization

Answer 14

kills by oxidation; Ex) flaming, incineration, hot-air sterilization

Question 15

boiling

Answer 15

can sanitize but doesn’t sterilize

Question 16

pressure cooking / autoclaving

Answer 16

steam under pressure; used for sterilization; kills all organisms and endospores; one of the most reliable and widely used sterilization techniques

Question 17

pasteurization

Answer 17

reduces spoilage organisms and pathogens; Ex) milk

Question 18

filtration

Answer 18

form of sterilization; passage of substance through screen-like material; used to prevent from being ruined by autoclaving

Question 19

one thing all forms of radiation have in common:

Answer 19

they work well on smooth, flat surfaces; not so well sterilizing large, porous objects

Question 20

ionizing radiation

Answer 20

damages DNA by causing lethal mutation; ionizes water to create reactive hydroxyl radicals; Ex) x-rays, gamma rays, electron beams

Question 21

nonionizing radiation

Answer 21

damages DNA by creating thymine dimers; Ex) ultraviolet

Question 22

microwaves

Answer 22

kill by heat; not especially antimicrobial

Question 23

bacteriostats

Answer 23

biological or chemical agent that stops bacteria from reproducing while not necessarily killing them; uses cold, dry and unfavorable osmotic conditions

Question 24

disk-diffusion method

Answer 24

evaluates efficacy of chemical agents; filter paper is soaking in a chemical and placed in a culture; looks for zone of inhibition around disks

Question 25

tincture

Answer 25

iodine solution in aqueous alcohol

Question 26

surfactant

Answer 26

wetting agent; paired with a chemical agent to cover a complicated shape

Question 27

antibiotic

Answer 27

a substance which was originally produced by a microorganism to kill other microorganisms

Question 28

decreasing order of resistance of microorganisms to chemical biocides

Answer 28

[most resistant] prions → endospores of bacteria → mycobacteria → cysts of protozoa → vegetative protozoa → gram-negative bacteria → fungi (including most fungal spores) → viruses without envelopes → gram-positive bacteria → viruses with lipid envelopes [least resistant]

Question 29

prions

Answer 29

proteins which can cause other proteins to misfold into more prions; hard to destroy; nonliving