Lab Quiz 2

Front 1

Purpose of Isolation Technique

Back 1

to obtain pure culture

Front 2

Define: Pure Culture

Back 2

all cell of a colony or culture had a common origin and are all descendants from one same parent cell

Front 3

Define: Colony

Back 3

Composed of billions of cells that originate from one parent cell

Front 4

Pure Culture Allows one to study

Back 4

1. Macroscopic (Colony) Characteristics
2. Microscopic (Morphology) Characteristics
3. Physiological (Biochemical) Characteristics

Front 5

Method of Obtaining a Pure culture and enumeration

Back 5

dilute out mixed bacterial culture to get individual, isolated colonies growing on agar plates

Front 6

Streak Plate Procedure (Isolation Technique)

Back 6

individual cells are spread out and separated which then develop into individual, isolated colonies, composed of billions of cells

Front 7

Pour Plate Procedure (Isolation and Enumeration Technique)

Back 7

Individual colonies develop and are separated (isolated) on the surface and below the agar surface (within the agar)

Front 8

Spread Plate Procedure (Isolation and Enumeration Techniques)

Back 8

individual colonies develop in the surface of agar plate

Front 9

Purpose of Enumeration Techniques of Microbes

Back 9

to find tilter in cells/ml of an unknown bacterial solution

Front 10

Cell Count Method

Back 10

a. counts number of bacteria in specific number of squares
b. use math formula to determine the titler (cels/ml)
c. Advantages
-quick and easy
d. Disadvantages
-exposed to living cells
-counts only small portion of the sample
-counts both living and dead cells

Front 11

Turbidometric Methods

Turbidity

Back 11

To determine cell densities

the cloudiness, which represents bacterial growth

Front 12

Spectrophotometer

Back 12

used to measure turbidity
1. determines the amount of light blocked by particulate material (ie) bacteria in a sample
2. measure the amount of light absorbed by microbes or the percentage of light transmittance

Front 13

Spectrophotometer

Back 13

note: absorbance increases linearly as bacterial concentration increases

Advantages:
quick and easy
Disadvantages
counts both living and dead cells
not that accurate
expensive

Front 14

Coulter Counter

Back 14

electronic counter machines that measures and counts particles
used in hospitals to count red blood cells
Advantages
quick and easy
Disadvantages
counts both living and deal cells
expensive

Front 15

Membrane Filter Method

Back 15

Disadvantages
incubation time 24 to 48 hours
hard to count colonies - small filter diameter
osmotic shock (bacteria lysis)
fastidious microbes will not grow

Front 16

Pour Plate Method

Back 16

countable colonies from 30 to 300

Front 17

Pour Plate Method

Back 17

Advantages
only counts living cells
standard text

Disadvantages
heat kills
time of incubation 24 to 48 hours
osmotic shock

Front 18

Spread Plate

Back 18

Advantages
doesn't involve heat
counts only living cell

Disadvantages
incubation time 48 hours
osmotic shock

Front 19

Dilution Factor

Back 19

all individuals dilutions need to get countable

Front 20

Platting Factor

Back 20

amount of stock solution pipetted and plated into plate

Front 21

Cultivation of Anaerobic Bacteria

Back 21

purpose: to determine the oxygen requirements of bacteria

Front 22

Obligate (Strict) Aerobes

Back 22

require 16% oxygen

Front 23

Obligate (Strict) Anaerobes

Back 23

require lack of oxygen

Front 24

Facultative Anaerobes

Back 24

(either/or) with or without oxygen (most prefer oxygen)
a. enzymes system allows them to utilize free oxygen or some alternate oxygen source such as nitrate
b. most grow best in the presence of oxygen
c. indifferents- show no preference of oxygen or alternate form

Front 25

Microaerophilic

Back 25

grow in the presence of minute quantities of free oxygen
require oxygen is small quantities (6%-10% of oxygen)

Front 26

Aerobic Bacteria

Back 26

have the enzyme catalase to breakdown acccumulation of toxic hydrogen peroxide from respiration

Front 27

Anaerobes Bacteria

Back 27

lack the enzymes catalase and are killed by the buildup of toxic H2O2

Front 28

Thioglycollate Broth Tubes

Back 28

1. glucose
2. cystine
3. sodium thioglycollate
1. lowers oxidation and reduction potential

Front 29

Resazurin Indicator

Back 29

Aerobic = red/pink color
Anaerobic = clear

Front 30

Aerobic Bacteria

Back 30

grows at the top and in the red area

Front 31

Microaerophilic Bacteria

Back 31

growth just below the surface in the red area

Front 32

Anaerobic Bacteria

Back 32

growth only in the clear area

Front 33

Facultative Anaerobes

Back 33

growth throughout the entire tube - red to clear area

Front 34

Brewers Anaerobic Jar

Back 34

creates only anaerobic conditions

Front 35

Platidium

Back 35

oxygen is converted to water on surface of platidium pellets

Front 36

Gas Pak

Back 36

add water, and it creates an anaerobic environment by releasing CO2 and H2 gases

Front 37

Indicator strip

Back 37

methylene blue
white color-anaerobic conditions
blue color - aerobic

Front 38

Candle Jar (microaerophilic environment)

Back 38

used to reduce the oxygen concentration to between 6% to 10% by increasing co2

Front 39

What does staining do?

Back 39

microorganisms are usually transparent so staining can also increase the size of certain features such as flagella which other wise would be too small to be observed with the compound light microscope.

Front 40

Stain

Back 40

an organic compound that contain a chromophore and an auxochrome group lined to benzene rings.

Front 41

Chromophore

Back 41

the portion of the stain which gives it color

Front 42

Auxochrome

Back 42

gives the stain the salt forming properties which is neccessary for the compound to adhere to the substrate

Front 43

electrical charge

Back 43

the electrical charge on bacteria is negative due to their protein and DNA molecules

Front 44

Basic Stains

Back 44

the balance of the electrical charge on the dye molecules is positive. it will for a salt with a metallic anion.
(ie) methylene blue (+) - chloride (-)
stain negatively charged bacteria due to protein and DNA

Front 45

Acidic Stains

Back 45

The balance of electrical charge on the dye molecules is negative (-). it will form a salt with a metallic cation
(ie) Na+ sodium + - eosinate (-)
stains red blood cells

Front 46

Neutral Stains

Back 46

a complex dye containing a dye acid with a dye based with an over all neutral charge

Front 47

Process od Heat Fixation

Back 47

1. adhering/fixing cells onto the slide
2. killing microbes (pathogens)
3. unfolding protein molecules and exposing postive and negative charges and this increasing the affinity of the specimen for the stain
4. preserve cell structure

Front 48

Simple stain

Back 48

a single stain used to stain a heat fixed smear (cells) in one application
(ie) methylene blue

Front 49

Negative Stain

Back 49

living organism are made visible by staining the background not the organism (ie) spirochetes
advantages
1. observe living organism
2. observe true cell morphology (no distortion of cell morphology from heat fixation or staining)

Front 50

Differential Stain

Back 50

stains which use more than one dye and
a. differentiates or seperates microbes into major groups (ie) gram stain
b. distinguish/differentiates structures (ie) spore stain. capsule stain

Front 51

Primary Stain

Back 51

first stain applied during a differential stain procedure

Front 52

mordant

Back 52

any chemical substance
(ie) iodine or physical agent
(ie) heat that allows the primary stain to adhere to substrate
(ie) cell wall, spore

a chemical mordant forms a complex with the primary stain and a physical mordant such as heat drives the primary stain into the substrate

Front 53

destain

Back 53

functions to remove the primary stain during differential stain procedure

Front 54

Secondary Stain

Back 54

a background stain applied to stained material to increase contrast

Front 55

Gram positive bacteria

Back 55

organism which retain the crystal violet iodine complex after using the ethyl alcohol acetone destain and remain purple

Front 56

Gram negative bacteria

Back 56

organisms which are destained by the ethyl alcohol acetone destain that results in the loss of crystal violet iodine complex. they are then counter stained with safranin and become pink/red

Front 57

Acid-Fast Bacteria

Back 57

organisms which are not readily stained but when stained during the acid fast staining procedure retain the color of the primary stain carbolfuchsin and stain red. acid fast positive bacteria are resistanct to decolorization with acid alcohol and they contain mycolic acid
(ie) mychobacterium

Front 58

Spore Stain

Back 58

the species of bacillus and clostridium produce endospores and exospores which resist staining. the spores can be stained by using a strong dye such as malachite green and heating (mordant) to drive the primary dye in. spores appear green and the vegetative cells are countered stained with safranin and appear pink/red