• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/35

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

35 Cards in this Set

  • Front
  • Back

generation time

time required for a cell to divide or a population of cells to double.



-it is most accurately calculated during the logarithmic growth phase

initial stationary phase

a. adjustment of bacteria to the new environment


b. few cells die due to osmotic shock

lag phase

a. lag in reproduction or cell division


b. cells are still viable and metabolically very active


c. cells increase in size


d. cells are getting ready to divide

logarithmic growth phase

a. maximum metabolism


b. maximum cell division


c. cell size becomes normal


d. shortest generation time found here


e. staining becomes most effective here

maximum stationary phase

a. number of cells dividing equals the number of cells dying


b. growth rate slows down due to accumulation of wastes, depletion of nutrients and over crowding


c. endospores and exospores

logarithmic death phase

a. cells die at a constant rate, much faster than divisions


b. few cells still survive, curve never reaches zero

sterilization

process of destroying all forms of life, including spores and viruses, utilizing either physical or chemical agents


disinfection

process by which all vegetative cells are killed, but not spores unless prolonged contact (20 min)

disinfectant

chemical substance used on non-living objects that is toxic to skin and mucous membranes, kills vegetative cells and viruses, but not spores unless prolonged contact



a. used on non living objects


b. toxic to living tissue


c. purpose- for disinfection of non-living tissue

antiseptic

chemical substance that is not toxic to skin and mucous membranes, kills vegetative cells but not spores



a. used on living tissue


b. non-toxic to living tissue


c. purpose- for disinfection of living tissue

bactericidal

a. inhibits growth and kills vegetative cells


b. cide means killer

bacteriostatic

a. inhibits growth but does not kill vegetative cells


b. temporary suspension of bacterial activities

sterilization by heat

involves denaturation of cell proteins and melting of membrane lipids

autoclave

-121 degrees


-15 lb./in^2


-15 minutes



use is limited in that you can not put heat sensitive materials and the pH of your material may be unintentionally reduced due to the acceleration of production of gases such as CO2

boiling of material

*not a true form of sterilization


considered an emergency sterilization

tyndallization

used to kill vegetative cells, moist steam at 100 C at atmospheric pressure for one hour on three days


-advantage: heat sensitive material can be processed

dry heat

160 C - 180 C for 1 1/2 hours


- no moisture, no pressure

phenol

Lister used it as an aerosol disinfectant to surgical instruments


-melts lipids


-destructs protein gates


-inactivation of enzymes

chlorhexidine

-denatures proteins

halogens

strong oxidizing agents that remove H-bonds


-denatures proteins (non functional)

alcohols

swabbing skin, instruments


-denatures proteins


-melts lipids

heavy metals

-high concentration of this = bactericidal effect


-noncompetitive inhibition of enzymes

surfactants

works to lower the surface tension of water and is often used in conjunction with other disinfectant to increase their effectiveness

quaternary ammonium compound

cationic detergents


a. enzyme inhibition


b. protein denaturation


c. disruption of cell membrane

oxidizing agents: hydrogen peroxide

a good antiseptic for irrigation of open and shallow wounds because of its cleansing action and the release of oxygen due to the presence of cellular catalase

ethylene oxide

denaturation of proteins in cell wall, cell membrane, enzymes


a. kills all microbes and spores


b. requires long exposure times 4-24 hours


c. toxic


4. explosive in pure form


5. high penetrating ability


6. medical supplies, plastic ware, mattresses, textiles

millipore filter

best way for heat sensitive materials


a. most commonly used


b. most effective


c. electrostatic forces do play some role in filtration


d. pore size: .45 microns, .22 microns .01 microns

hepa filter

a. laminar flow hoods


b. filtering exhaust systems like biohazard buildings

ultraviolet light

260 nanometers causes most severe damage to the DNA molecule (bactericidal effect)


-formation of thymine-thymine dimers



disadvantage:


a. poor penetration power


b. little effect on spores

photoreactivation

90% effective


photoreactivation enzyme


a. recognize thymine thymine dimer


b. breaks thymine thymine dimer


c. restores normal DNA structure


excision

10% effective


DNA polymerases and DNA ligases


a. recognize T-T dimer


b. excision and removal of T-T dimers


c. repair damaged DNA by synthesis of new DNA to fill gap

ionizing radiation

causes splitting or ionization of water molecules


-formation of free radicals


-denaturation of proteins and DNA

gamma rays

have greatest penetration power


-used in food and preservation of spices

pateurization

controlled heating below boiling


a. kills pathogens


b. reduces total number of normal flora

4 sterilization of milk

under vacuum, less than 5 seconds


-74C---140C---74C


-used for coffee creamers and areas of poor refrigeration