Chapter 4 & 5 Flashcards
Polymer-encased community of microorganisms
Biofilm
A culture medium of exact chemical composition; generally used for experiments where nutrients must be precisely controled.
Chemical defined medium
A culture medium that contains protein digests, extracts, or other ingredients that vary in their chemical composition
Complex medium
A culture medium with an ingredient that certain microorganisms change in a recognizable way; used to differentiate based in metabolic traits
Differential medium
Stage in the growth curve during which cells divide at a constant rate; generation time is measured during this period of active multiplication
Exponential (Log)Phase
Organisms that grow best if O² is available, but also grow with out it.
Facultative Anaerobe
The time it takes for 1 population to double in number
Generation Time
Organisms that requires O²
Obligate Aerobe
Organsim that cannot multiply, and is often killed, in the presence of O²
Obligate Anaerobe
A population descended from a single cell
Pure culture
A culture medium with an ingredient that inhibits the growth of microbes other than the one being sought
Selective medium
Asexual process of reproduction in which one cell divides to form 2 daughter cells
Binary fission
Planktonic cells are …
Free floating
Mixture of hydrophobic polyermes ,polysaccharides, DNA, and proteins secreted by microbial cells as part of biofilm formation
Extracellular Polymeric Substances
Simplest and most commonly used technique for isolating bacteria; a series of successive streak patterns is used to sequentially dilute on the surface of an agar plate.
Streak-plate method
A system such as a tube, flask, or agar plate where nutrients are not replenished and waste are not removed as microorganisms grow
Closed system
Bacterial growth curve phase where there is ATP synthesis but no increase in cell numbers
Lag phase
When are bacteria most sensitive to antimicrobial medications and why?
During exponential growth phase
They are dividing and thus penicillin works best during this time
Compounds synthesized by a cell during the log phase
Primary metabolites
Microbial compounds that are made for purposes other than growth are called
2nd metabolites
Antibiotics are an example of this type of metabolite
2ndary
Primary metabolites are synthesized during the period of ______ . 2ndary metabolites begin to be synthesized in ________
Active multiplication / Early Log Phase
Late log phase
When neutrient levels are too low to sustain life and the stage where the number of viable cells remains constant
Stationary Phase
What does a chemostat do?
Allows nutrients to be added and waste to be removed from a bacterial growing enclosed
When organisms use O² in aerobic respiration, harmful derivatives called __________ form as by products
Reactive Oxygen Species
Harmful derivatives of O² such as superoxide O²- and hydrogen peroxide H²O²
Most organisms that grown in oxygen produce this enzyme that turns superoxide into O² and hydrogen peroxide
Superoxide dismutase
The enzyme catalase does …
Converts hydrogen peroxide into O² and water
Dehydration and shrinkage of cytoplasm from the cell as a result of diffusion of water out of a cell
Plasmolysis
______ require high level of salt
Halophiles
Hetrotrophs use ____ carbon
Autotrophs use _____ carbon
Organic
Inorganic
The conversion of nitrogen to ammonia is called
It is then incorporated into amino acids
Nitrogen fixing
Nutrients that limit growth because it is present at the lowest level concentration relative to need
Exp Phosphorus & Iron
Limiting nutrients
Compounds that a particular bacterium require in a growth medium because they cannot synthsize them
Growth factors
Fastidious means
Having complicated nutritional needs
This type of medium contains variety of Ingredients such as meat juices, digested proteins, & Blood agar
Complex media
What is chocolate agar and which type of media is it an example of
Lysed red blood cells + supplements
Complex media
Blood agar is which types of media.
Explain how this media is used to distinguish between Streptococcus bacteria
Describe alpha and beta lysis
Complex & Differential
Streptococcus pyogenes cause Beta lysis, clear zone around the colony
Alpha is characterized by a greenish discolorization
MacConkey agar is this type
It contains lactose and ph indicator that turns bacteria that ferment sugar Ph indicated pink-red.
Differential and selective
Culture method that provides conditions to enhance the growth of 1 particular species in a mixed population
Enrichment Culture
How does direct microscope count work to determine the number of cells?
Cells are put on a square with a known amount of water. This number is averaged and multiple by the volume of water
Cell counting and Direct cell count machines have 1 major disadvantage ….
It can’t distinguish between living and dead cells
To count colonies on an agar plate which 2 methods can be used.
Spread-plate method
Pour-plate method
Which cell count method is used to count with the least possible bacteria
Such as a lake
Membrane filtration
Tech used to obtain statical estimates of cell numbers,a sample is successively diluted until the subsequent dilution receives no cells
Most probable number (MPN) method
The cloudiness of a sample is called….
Turbidity
This cell counting method is very rapid and used routinely. A correct is done between the fluid first than the fluids cloudiness is measured with a Spectrometer
Turbidity
_______ counts determine the number of cells capable of multiplying
Plate
________ estimates the cell concnetration
Most probably number MPN
______ use inorganic compounds for energy and derive their carbon from CO ²
Chemolithoautotrophs
Organisms that use light as the energy source and organic compounds as a carbon source
Photoheterotrophs
Organisms that obtain energy and carbon from organic compounds
Chemoorganoheterotrophs
A candle jar makes this type of environment
High Co2
This type of cell count involves counting cells through a microscope
Direct count
An isolated cell on an agar plate will….
Form a single colony
Population of prokaryotic cells undergo 5 stages
Lag
Exponential growth log
Stationary
Death
Prolonged death
Is boiling an example of sterilization
No, endospores can survive it
Difference in useage in High-Temperature-Short-Time &
Ultra-High-Temperature method of pasteurization
HTST 72C for 15 seconds (Milk / Ice Cream)
UHT 140C few seconds (juice boxes/ boxed milk)
Chemical endoscopres and heat tape are 2 ways to verify an autoclave is working
True or False
True
Give an example of Dry heat (Incineration)
Moist heat used to destroy microbes
Dry = The loop in class
Moist = Auto Clave
The wavelength is ________ proportional to the frequency
Radiation with _____ waves has a _____ frequency
Inversely
Short / High
Ionozing radiation harms cells by destroying ______
It also reacts with O² to produce _____________
DNA
reactive oxygen species
Which are most susceptible to Ionizing Radiation
Which are the least
Gram-negative Salmonella & Pseudomonas
Bacterial Endospores
Categories of Germicidal Potency
These destroy all microbes and endospores in about 6 -10 hrs
Used to treat critical instruments
Steriliants
Categories of Germicidal Potency
These detroy all viruses and vegetative microorganisms Not Endospores.
Used to treat semi critical instruments
Contact with mucos membranes and non-intact skin
High level disinfectants
Categories of Germicidal Potency
Destroys all vegetative bacteria (including mycobacteria)
Disinfectant Non Critical instruments
Intermediate level disinfectants
Categories of Germicidal Potency
Destroy fungi, vegetative (Not Mycobacteria) , most viruses
Used on floors, walls, and furniture
Low-level disinfectants
Aqueous solution used as antiseptics to clean skin before it is broken (needle) & a disinfectants for cleaning instruments
Alcohols
Glutaraldehyde and ortho-phthalaldehyde are used to sterilize medical instruments.
Formalin is used in vaccine production and to preserve biological specimens
Aldehydes
Used in a variety of cleaning products disinfectant solutions, antiseptics by Healthcare & prescription mouthwash.
Incorporated into catheters and surgical mesh
Biguanides (chlorhexidine)
Commonly used to sterilized medical devices
Ethylene Oxide Gas
_____ is used in topical dressings to prevent infection of burns.
Silver
Used to disinfect drinking and waste water
Ozone
____ is used to sterilize juice and milk containers
______ is a widely used to disinfect and sterilez medical devices
Hydrogen peroxide
Peracetic acid
________ were common antiseptics in the past but there are now safety concerns
Triclosan & hexachlorophene
Quaternary Ammonium Compounds
(Benzalkonium chloride) are cationic detergents that….
Disinfectant of inanimate objects and preserve non food substances
Not very toxic, safe for counter tops
Benzoic, sorbic, propionic are what
Acids that are added to food to preserve
What do Nitrates & Nitrites do
What bacteria do they prevent
Prevent bacterial growth
Give preserved meats a pink color
Endospores & Clostridium botulinum
Ultra violet light damages the structure and function of …
Nucleic Acid
Pseudomonas fluorescents Gram-positive or Gram-negative
Gram-negative
Time, temp, pressure required to killed everything
121 Celsius, 15 lb sq In, 15 minutes
