Microbiology - Test #2

Front 1

facts about bacteria growth (4)

Back 1

facts:
*bacteria divide quickly by binary fission
*under optimal conditions for growth a few bacteria can become large in number in a short time
*by knowing the requirements for growth, we can encourage the growth of wanted bacteria we wish to study
*we can discourage the growth of unwanted bacteria (infections, contaminant, pathogenic)

Front 2

requirements for bacteria growth (3)

Back 2

physical requirements:
a) temperature
b) pH
c) osmotic pressure

Front 3

bactericidal (biocidal); germicide

Back 3

agents that result in the cell being killed

Front 4

bacteriostatic

Back 4

agents that inhibit bacterial growth that do not kill, when the agent is removed, growth resumes.
ex. colds, hypertonic solution, dessication (drying)

Front 5

mesophiles

Back 5

bacteria with an optimal temp range of 25-40*C (37-98.6*F)
- most common including:
a) normal microbiota
b) most pathogens
c) unknown bacteria, in BCC labs

Front 6

psychrophiles

Back 6

- 'cold-loving'
- can grow at 0*C
- optimum growth temp 15*C
- found in polar regions deep in the oceans; on top of high mountains

Front 7

psychrotrophs

Back 7

-can grow at 0*C
-high optimum temp 20-30*C
-CANNOT grow above 40*C
- found in refrigerator food spoilage

Front 8

thermophiles

Back 8

- heat-loving bacteria
- extreme high temp
- optimum growth temp 50-60*C
-optimum temp 121*C=245*F

Front 9

pH

Back 9

-most microorganisms grow at pH7
-the wrong pH, the unfavorable
pH, denatures enzymes or
BACTERICIDAL
-low pH inhibits most bacteria, not fungi

Front 10

buffers

Back 10

in the microbiological media prevent sudden, drastic chnages in pH and maintain a specific pH

Front 11

acidophiles

Back 11

-acid-loving
-microorganisms that can grow at a low (acidic) pH

Front 12

basophiles

Back 12

alkaline (acid)-loving

Front 13

osmotic pressure

Back 13

the amount of water outside the cell as there is inside

Front 14

hypertonic

Back 14

-less water outside the cell than inside
-water leaves the cell

Front 15

plasmolysis

Back 15

-the shrinkage of a cell's contents in a hypertonic solution
-the cell membrane, collapses but not the entire cell because of its rigid external cell wall. BACTERIOSTATIC

Front 16

halophiles

Back 16

-salt-loving
-live in very salty (HYPERTONIC) environment due to rigid cell walls

Front 17

nutrients

Back 17

-chemicals released when large complex food molecules are broken
1) energy source
2) building blocks of macromolecules
3) regulated & control cellular functions (vitamins & minerals)

Front 18

macronutrients

Back 18

- >10%
-carbon, nitrogen, phosphorus, sulphur

Front 19

micronutrients

Back 19

- <1%
-trace elements (inorganic metallic ions)
-organic growth factors (vitamins & minerals)

Front 20

carbon

Back 20

-makes ALL organic compounds the backbone of living matter (cells)
-50% of a cell's dry weight

Front 21

autotrophs

Back 21

organisms that use inorganic compounds (Co2 gas used)
-ie. photosynthetic organisms
-5% of the cell

Front 22

heterotrophs

Back 22

-fed by others
-organisms that obtain their carbon from pre-formed organic molecules
-95% of the cell

Front 23

nitrogen

Back 23

-synthesis of proteins (amino acids)
-synthesis of nucleotides (DNA, RNA, ATP) (CHONPS)
-14% of the cell

Front 24

sulfur

Back 24

- make amino acids
-4% of the cell

Front 25

phosphorus

Back 25

-make phospholipids for DNA, RNA, ATP (nucleotides)

Front 26

oxygen

Back 26

a highly reactive element that cause formation of free-radicals

Front 27

reducing media

Back 27

a microbiological growth medium that chemically reacts with dissolved gaseous oxygen & removes oxygen from the medium
ie. sodium glycolate broth, "fluid thio"

Front 28

obligate aerobe

Back 28

growth occurs only where high levels of oxygen have diffused into the medium

Front 29

obligate anaerobes

Back 29

growth occus only where there is no oxygen

Front 30

facultative anaerobes

Back 30

growth is best wehre most oxygen present, but occurs throughout the tube, although not evenly

Front 31

aerotolerant anaerobes

Back 31

growth occurs evenly; oxygen has no effect

Front 32

microaerophiles

Back 32

growth occurs only where a low concentration of oxygen has diffused into medium

Front 33

free-radicals

Back 33

chemically wastable molecules extensive lethal cellular damage (cause oxydation; electrons)

Front 34

trace elements

Back 34

- inorganic growth factors
- co-factors:
iron
copper
molybdenum
zinc

Front 35

co-factors

Back 35

inorganic metallic ions that attach to enzymes and make the enzyme function

Front 36

culture

Back 36

microorganisms growing in or on a nutrient substance (medium)

Front 37

medium

Back 37

any nutrient substance that can support microbial growth

Front 38

agar

Back 38

-a carbohydrate found in red sea weeds
*no microorganism can break down agar
*it melts at 100*C/212*F
*incubation is 37*C
*hardens at 45*C (warm but still melted agar won't kill heat-sensitive microorganisms)

Front 39

organic growth factors

Back 39

organic non-protein molecules ie. vitamins: ABCDEK
-act as co-enzymes

Front 40

co-enzymes

Back 40

organic non-protein molecules such as vitamins that attach to enzymes and make the enzyme functional

Front 41

criteria for a useful medium

Back 41

1) must supply all the physical and chemical requirements for microbial growth
2) able to be sterilized (without breakdown)
3) able to be incubated

Front 42

chemically-defined medium

Back 42

exact chemical composition is known (every ingredient to an exact amount )

Front 43

selective medium

Back 43

inhibits growth of unwanted microorganisms BUT allows the growth of wanted microorganisms
ie. pH, salt, EMB dyes, antibiotics

Front 44

complex medium

Back 44

a microbial growth medium whose exact chemical compositions isn't known
-is made up of extracts or digests from plants, meats, or yeasts
the batch differs if it is not uniform
ie. heterotrophic

Front 45

differential medium

Back 45

indicates color change due to some unique metabolic process or product

Front 46

enrichment culture

Back 46

-selective medium that is designed to grow to small microorganisms to become large in inoculum

Front 47

reducing medium

Back 47

chemically reacts with dissolved oxygen remove to gaseous oxygen from the medium to create an anaerobic environment

Front 48

pure culture

Back 48

only that one specific species (type of microorganisms)

Front 49

streak plate method

Back 49

physically separating bacteria out on the surface of solid media far enough apart so that individual cells can grow in to pure colonies

Front 50

standard plate count

Back 50

serial dilution (setting a series of sterile water blanks, and diluting the bacteria and the pour plate method so that you have individual cells that can grow into pure colonies)

Front 51

deep-freezing

Back 51

the bacteria has to be suspended in an anti-freeze so ice crystals don't form
ie glycerine, ethylene glycol
-50*C-95*C (bacteriostatic)

Front 52

freeze-drying

Back 52

fast-freezing, then in a vacuum, the ice sublimates, turns to a gas, not a liquid
(LYSPHILIZATION)
(BACTERIOSTATIC)

Front 53

binary fission

Back 53

an asexual form of reproduction in which one cell splits into two genetically identical cell

Front 54

generation time

Back 54

-the time needed for a cell to divide; or a population to double
-or a population to double
-vary by species (20' propagate)
-vary by physical or chemical requirements

Front 55

lag phase

Back 55

-occurs after the inoculum is put into sterile media
-no cells are drying but no new cells are forming
a) the cells are adjusting to the new media
b) this is a biochemically acive stage in which the cells are preparing for rapid, intense growth

Front 56

log phase (logarithm)

Back 56

-exponential growth phase
- a period of rapid cell division (cell growth)
-all cells are metabolically active and dividing.
-the shortest generation time
-all cels are sensitive to any physical or chemical agents that could interfere with growth
-all cells can be producing a product

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stationary phase

Back 57

-occurs when microorganisms begin to use up the nutrients in the media
-the accumulation of metabolic wastes are beginning to affect bacterial growth
-the phase of the bacterial growth where # of new cells = # of dying cells

Front 58

death phase

Back 58

-decline phase
-because the nutrients on the media have now been used up and the accumulation of metabolic wastes has reached dealy toxin levels; more cells are dying then forming endospores

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1) direct method
2) indirect method

Back 59

methods of counting bacteria

Front 60

direct method

Back 60

-standard plate count
-serial dilution: pour plate
(+) viable cell count - very accurate because living cells that grow into viable colonies are counted
(-) too many steps, each a risk for contamination
(-) uses a lot of lab equipment
(-) takes 24 hrs. for results

Front 61

indirect method

Back 61

-aseptic technique is critically applied
-many tubes, pipette, timing (secs to min), dilution factor (1:10) (1:100) (1:1000), etc.
(+) immediate results
(+) only one step procedure, essentially no possible contamination
(-) not as accurate because living cells, dirt, fingerprints can contribute to light absorbency

Front 62

turbidity

Back 62

refers to cloudiness in the broth, usually due to the number of cells. "the more turbid, the more cells"

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spectrophotometer

Back 63

an instrument that measures light absorption

Front 64

light transmittance

Back 64

the amount of light that goes thru the sample and is not absorbed

Front 65

light absorbance

Back 65

the amount of light that does not leave the sample

Front 66

sterilization

Back 66

the complete physical or chemical destruction or removal of all forms of microbial life, including endospores

Front 67

-commercial sterilization

Back 67

-sufficient heat treatment to kill the heat-sensitive endospores of a specific deadly bacteria (clostridium botulism)
-any endospores of thermophilic bacteria that may survive, do not germinate under normal storage conditions

Front 68

disinfection

Back 68

the destruction of vegetative pathogens on non-living surfaces and objects

Front 69

disinfection

Back 69

the destruction of vegetative pathogens on non-living surfaces and objects

Front 70

antisepsis

Back 70

the destruction of vegetative pathogens on living tissues, skin, mucous membranes

Front 71

degerming

Back 71

-physically remove microorganisms from a limited area of the skin
-mechanically removing them by scrubbing soap and water as an alcohol swab

Front 72

sanitization

Back 72

treatment intended to lower microbial counts on eating and drinking utensils to safe public health levels

Front 73

bactericidal

Back 73

treatments that result in the killing of the cell

Front 74

biocide (germicide)

Back 74

kill microorganisms

Front 75

sporocide

Back 75

kills endospores

Front 76

fungicide

Back 76

kills fungi

Front 77

viruside

Back 77

kills viruses

Front 78

tuberculocide

Back 78

kills mycobacterium tuberculosis (TB)

Front 79

sepsis

Back 79

-decay, putrification
-the presence of microorganisms in normally sterile tissues
-the presence of bacteria in blood multiplying

Front 80

asepsis

Back 80

any procedure, treatment that prevents contamination, infection

Front 81

factors that influence the effectiveness of antimicrobial treatments (physical and chemical methods of control)

Back 81

1) the number of microorganisms
2) environmental influences: the presence of organic material (ie body fluids - can weaken and even reduce completely the actions of these methods)
3)time of exposure: autoclave 15psi=121*C/245*F=15mins
4) microbial characteristics: from least resistant to most resistant

Front 82

microbial characteristics (factors that influence the effectiveness of antimicrobial treatments)

Back 82

from the least resistant to most resistant
1) endospores
2)mycobacteria: TB can't gram-stain
3) Gram (-)
4) Gram (+) - least resistant because pores are open

Front 83

actions of antimicrobial agents

Back 83

1)alteration of cell membrane permeability-damage to the cell membrane and it loses selective permeability
-LYSE - destruction of cell wall
2) damage to proteins - denature (coagulation) precipitation
3) damage to nucleic acids (DNA) especially: (DNA=RNA=Proteins) makes new chromosomes BAD!!!

Front 84

physical methods of microbial control

Back 84

A. Heat
1. moist heat
2. dry heat
a. flaming
b. dry heat
3. Pasteurization
B. Filtration
C. Dessication
D. Osmotic pressure
E. Radiation
a. non-ionizing radiation
b. ionizing radiation

Front 85

heat

Back 85

very old, but still widely used type of microbial control

Front 86

moist heat

Back 86

very effective because water is a good conductor of heat
a) boiling water - limited to 212*F
b) autoclave - a device that uses steam under pressure 15 psi=245*F+15mins=sterilize (121*C)

Front 87

dry heat

Back 87

air acts as an insulator so a larger exposure time and higher temp as needed

a) flaming - Bunsen-burner incineration; denatures proteins
b) dry heat sterilization (hot-air)

Front 88

Pasteurization

Back 88

a brief mild heating of a liquid such as milk, beer, wine, cider to kill the heat-sensitive pathogens and or spoilage without destroying the flavor or quality of that liquid

Front 89

filtration

Back 89

a physical method of control by physically preparing microorganism from suspending liquid or gas (air) by passage through screen-like device
*doesn't use heat so that heat-sensitive (heat labile) solutions media, etc. can be sterilized

Front 90

dessication

Back 90

drying by evaporation (bacteriostatic)

Front 91

osmotic pressure

Back 91

bacteria in a hypertonic solution loses water, plasmolysis occurs, (bacteriostatic)

Front 92

radiation

Back 92

physical method of microbial control to sterilize

Front 93

non-ionizing radiation

Back 93

-long wavelengths = 265nm
-slow, low energy particles
-not very penetrating
-damages cellular DNA
ex. UV light (in lab)

Front 94

ionizing radiation

Back 94

-short wave lengths
-fast-moving particles, high energy
-very penetrating
-ionizes water to make free-radicals
-does extensive lethal cellular damage
ex. x-rays, gamma rays

Front 95

free-radicals

Back 95

chemically-unstable molecules

Front 96

chemical methods of control

Back 96

1) concentration
2) temperature
3) organic material can reduce the effectiveness of some chemical agents
4) pH

Front 97

concentration

Back 97

dilution

Front 98

temperature

Back 98

has an effect on exposure time
room temp (20*C = 68*F)

Front 99

what happens if the chemical come into contact with the material to be disinfected?

Back 99

oils, organic material can reduce the effectiveness if some chemical agents

Front 100

disc diffusion method

Back 100

- a way to evaluate the effectiveness of disinfectants/antiseptics
-uses sterile paper discs dipped in a chemical agent and placed on an agar (TSA) that had previouly been swabbed with
- E. Coli = pseudomonas aerginousa (G-)
- Staph a (G+)

Front 101

BPME disc test that displays zone of inhibition

Back 101

B- bleach
P - phenol
M - mouthwash
E - ethanol

Front 102

bleach

Back 102

best, full-spectrum disinfectant; works on all G+ and G- bacteria

Front 103

zone of inhibition

Back 103

an area of no growth around a paper disc on an agar plate

Front 104

phenol

Back 104

the first accepted and widely used chemical agent for aseptic surgery
- used by Joseph Lister
-acts to denature proteins
not weakend or neutralized by organic material
-source was carbolic acid

Front 105

why phenol isn't generally used anymore?

Back 105

1) disagreeable odor
2) irritating to the skin
3) kills WBC
-used as a standard of comparison

Front 106

phenolics

Back 106

-compounds derived from phenol
-it reduces the irritating & disagreeable properties of phenol but retains the killing properties
-denature proteins/disrupt cell membrane
-not affected by organic material
ex. lysol or Cresol (to preserve wood)

Front 107

bis-phenols
"bis" = bridge

Back 107

a compound derived from two phenolics bridged together
-disrupts cell membrane
ex. hexachlorophene (phisoHex) - once used as a topical antiseptic
triclosan - use on cutting boards; overuse means bacterial resistance
-effective against G+, G-

Front 108

Chemical Agents

Back 108

1) phenol
2) phenolics
3) bis-phenols
4) halogens
5) alcohols
6) heavy metals & their compounds
7) surface active agents
8) quartenary ammonium compounds
9) aldehydes
10) gaseous chemosterilizers
11) peroxygens and other oxygens

Front 109

halogens

Back 109

- are powerful oxidizers
- inhibit protein functions
-alter cellular components
ie. chlorine
- gas is used in water disinfection
-calcium hypochlorite (chloride of lime use by Semmelweiss)
-sodium hypochlorite (bleach)

Front 110

iodine

Back 110

-tincture -an aqueous solution in alcohol

Front 111

iodophore

Back 111

iodine with an organics detergent

Front 112

alcohols

Back 112

are a goood degermer

Front 113

degermer

Back 113

agent that physically remove microorganisms from a limited area of the skin

Front 114

what a good degermer does

Back 114

-evaporates quickly
-doesn't leave residue

Front 115

why alcohols are bad antiseptics

Back 115

-evaporates quickly
-doesn't leave residue
-denature/coagulate proteins

Front 116

heavy metals & their compounds

Back 116

-metals form cations (+) ions
-metallic elements are attracted to acid will bind to enzymes

Front 117

oligodynamic action

Back 117

the ability of small amounts of heavy metal ions to exhibit antimicrobial activity
ex. silver zinc, copper, mercury, mercurochrome - mercury compound

Front 118

surface active agents

Back 118

-surfactants
-soaps & detergents
-lower the surface tension of water
-also act as emulsifier

Front 119

emulsification

Back 119

breaking down lipids (oils) into small droplets (globules) that go into solution

Front 120

quarternary ammonium compounds

Back 120

-a group of detergents derived from the ammonium ion
-disrupt cell membranes of bacteria
-odorless
-colorless
-stable
-easily diluted in water
-non-toxic
-works well against G+ bacteria
-tasteless
*does NOT work against G- bacteria bec of outer cell membrane

Front 121

aldehydes

Back 121

-group of liquid chemical agents
-formalin, formaldehyde, gluteraldehyde
-inactive proteins
-gluteraldehyde is one of the few liquid chemical sterilents (long exposure time leaves a residue)
-preserve specimens

Front 122

sterilents

Back 122

means long exposure time leaves a residue

Front 123

gaseous chemosterilizers

Back 123

-device that uses a gas to sterilize
-sterilizing gas is ethylene oxide - very penetrating,
-doesn't use heat,
-denatures proteins,
-sporocidal,
-used to sterilize heat-sensitive equipment
-doesn't leave a residue

Front 124

explosive gas

Back 124

mix it with an inert gas

Front 125

peroxygens and other forms of oxygen

Back 125

-hydrogen peroxide ozone
-peralcitic acid
-powerful oxidizers that do extensive lethal cellular damage
-forms free radicals
-chemical sterilant

Front 126

microbial characteristics

Back 126

an important influence on the effectiveness of physical and chemical methods of microbial control

Front 127

endospores

Back 127

most resistant bacteria

Front 128

G-

Back 128

less resistant (has an outermembrane)

Front 129

G+

Back 129

least resistant

Front 130

metabolism

Back 130

all the chemical reactions within a cell or organism; a life process

Front 131

catabolism

Back 131

decomposition,
exergonic
exothermic
(A-B = A+B+energy)

Front 132

anabolism

Back 132

synthesis
endergonic
endothermic
(A+B+energy = A-B)

Front 133

ATP

Back 133

-is energy-carrying molecule of cells
-ATP can't make another ATP
-energy is transferred from one substance to ATP (the energy-carrying molecule)
-heat
-work
-ATP supplies the energy to drive most anabolic reactions

Front 134

ATP: metabolic pathways

Back 134

1. aerobic respiration
2. anaerobic respiration
3. fermentation

Front 135

metabolic pathways

Back 135

energy is transferred to ATP in a series of biochemical metabolic steps

Front 136

activation energy

Back 136

the amoung of energy needed to begin a chemical reaction

Front 137

substrate

Back 137

the substance that is catalyzed by the enzyme

Front 138

apoenzyme

Back 138

protein part of an enzyme

Front 139

co-factor

Back 139

inorganic metallic ione that binds to an enzyme

Front 140

co-enzyme

Back 140

a non-protein organic molecule that binds to an enzyme

Front 141

holoenzyme

Back 141

the complete functional enzyme

Front 142

active site

Back 142

area on an enzyme where a specific substance binds

Front 143

factors influencing enzymatic activity

Back 143

temp-optimal 37*C: "low slow; high die"
pH- optimal pH7
substrate concentration-saturation pt of enzyme activity vs substrate concentration
inhibitors-chemicals that bind to enzymes and stop enzyme activity

Front 144

oxidation

Back 144

the loss of electrons from an atom or molecule

Front 145

reduction

Back 145

the gain of electrons by an atom or molecule

Front 146

oxidation-reduction (redox) reactions

Back 146

energy is transferred from the molecule to ATP in a series of redox reactions (ie glucose to ATP)

Front 147

phosphorilation

Back 147

adding a phosphorus group to a molecule

Front 148

substrate level phosphorilation

Back 148

the phosphate is directly transferred from one compound to ADP

Front 149

oxidative phosphorilation

Back 149

glucose is used to make ATP from redox reactions

Front 150

glycolysis

Back 150

doesn't end product; pyruvate acid (2) added

Front 151

aerobic respiration

Back 151

final electron is oxygen; water is end product

Front 152

anaerobic respiration

Back 152

final electron is inorganic and molecule cannot make water; not efficient

Front 153

fermentation

Back 153

final electron is organic molecule to energy-reduced organic compound

Front 154

phototrophs

Back 154

light as energy source

Front 155

chemotrophs

Back 155

oxidation of chemical compounds as energy source

Front 156

autotrophs
"self-feeding"

Back 156

make own organic molecules CO2 gas = inorganic
5%

Front 157

heterotrophs
"fed by others"

Back 157

use pre-formed organic molecules
95%

Front 158

photoautotrophs

Back 158

light + carbon

Front 159

chemoheterotrophs

Back 159

organic compounds (glucose)

(ie animals, protozoans, fungi, most bacteria)

Front 160

chemoautotrophs
"rock-eaters or litotrophs"

Back 160

inorganic chemical compounds + inorganic CO2 gas

Front 161

saprophytes

Back 161

decomposers; energy from dead organic materials

Front 162

parasites

Back 162

nutrients from a living host

Front 163

photoheterotrophs

Back 163

light + organic compounds (fatty acids, organic acids, carbohydrates, alcohols)