EXAM 3 P1

Question 1

static agents

Answer 1

stops growth of an organism

Question 2

cidal agents

Answer 2

stops and kills an organism

Question 3

lytic agents

Answer 3

stops and lyses a cell

Question 4

minimum inhibitory concentration

Answer 4

MIC
in a liquid medium
a series of identical tubes contain sterile growth mediums. various concentrations of a chemical agent are added.
there is a zero chemical tube and a zero uninoculated tube for controls.
we’re trying to define the minimum concentration required to completely inhibit growth

Question 5

agar diffusion method / zone of inhibition

Answer 5

done on plates, solid medium
a small amount of started culture is spread. we’re trying to get a lawn of growth rather than single colonies. immediately after spreading, sterile paper discs that’ve been soaked with chemicals are placed on top. we’re looking for chemicals that inhibit growth

Question 6

zones of inhibition

Answer 6

come in different sizes
large zones of inhibition means high sensitivity and low resistance. small zones of inhibition mean low sensitivity and high resistance.

Question 7

characteristics of MIC and agar diffusion method

Answer 7

they’re specific for the species and strain, the chemical concentration / agent, the medium, and the environment

Question 8

sterilants

Answer 8

strongest antimicrobial treatment
sterilizes the environment where they are placed. kills all microorganisms, including spores.
examples include chlorine gas, chlorine dioxide, and H2O2 vapor, often used in hospitals

Question 9

spores

Answer 9

the most resistant form of life

Question 10

disinfectants

Answer 10

kill all microorganisms except spores

examples include sodium hypochlorite (bleach), chlorine or ozone in drinking water, and some alcohols

Question 11

sanitizers

Answer 11

don’t kill everything, but significantly reduce the number of microorganisms.
relatively nontoxic to humans and are used in food preparation
examples include cationic detergents and sodium hypochlorite (bleach)

Question 12

antiseptics / germicides

Answer 12

kill or inhibit microorganisms but are nontoxic to human tissue
examples include alcohol, H2O2 (hydrogen peroxide), and iodine compounds

Question 13

antibacterial chemotherapeutic agents

Answer 13

aka antibiotics
something that inhibits bacteria
do not work on fungi or viruses
needs to target an essential cell process

Question 14

streptomycin, chloramphenicol, and clindamycin

Answer 14

targets for protein synthesis

Question 15

vancomycin

Answer 15

target for peptidoglycan synthesis

effective against species that have become resistant to penicillin

Question 16

broad spectrum

Answer 16

target a wide variety of different bacteria

examples are tetracycline and penicillin

Question 17

narrow spectrum

Answer 17

targets a specific area
micro bacteria cause some serious diseases (tuberculosis and leprosy)
prevented with isoniazid

Question 18

challenges of making antifungals and antivirals

Answer 18

fungi are eukaryotes like us

viruses use our cellular enzymes for reproduction

Question 19

antifungals

Answer 19

cell membranes contain a fungus specific lipid that can be targeted, known as an ergosterol inhibitor
cell walls are made of chitin, not produced by humans

Question 20

antivirals

Answer 20

azidothymidine AZT targets reverse transcriptase
protease inhibitor, anti HIV
interferon is produced in response to a virus infection

Question 21

naturally resistant

Answer 21

have no target or they’re impermeable

examples include mycoplasma (no peptidoglycan wall)

Question 22

modify the target of antibiotics

Answer 22

mutations in the genome that modify the cell’s normal enzyme

Question 23

medical misuse of antibiotics

Answer 23

incomplete course of treatment (stopping when you feel better)
use for non-bacterial or minor infections

Question 24

agricultural misuse of anitbiotics

Answer 24

use in healthy animals simply for growth promotion