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Microbiology Pt 2
Concepts and words from Tortora,Funke,Case, chs 6,7,18,20
134
Biology
Undergraduate 2
10/23/2008

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Term
Hyperthemophiles (extreme thermophiles)
Definition
These are found in volcanoes. One species can grow at 121°C (boiling water is 100°C). These are members of Domain Archaea.
Term
Mesophiles
Definition
Grow well at room temperature and at body temperature. Most human pathogens are -----s. Some can divide every 20 minutes.
Term
Psychrotrophs
Definition
Grow at slightly warmer temperatures than cold-loving ones. These microbes can grow better than most other microbes at near freezing temperatures and can grow well at room temperature. These microbes are responsible for spoiling food in the refrigerator.
Term
pH
Definition
refers to the concentration of H+ in a solution.
Term
High pH (pH > 7) refers to: (2 names)
Definition
a basic solution (alkaline).
Term
Low pH (pH < 7) refers to
Definition
an acidic solution.
Term
Buffer
Definition
solution that resists changes in pH
Term
Acidophiles
Definition
microorganisms that grow at low pH; very few bacteria; yeasts and fungi can grow and spoil at pH 5-6
Term
Osmotic pressure
Definition
pressure caused by differences in solution concentrations across a selectively permeable membrane
Term
Isotonic
Definition
concentration same on both sides
Term
Hypotonic
Definition
concentration is less on this side than other side
Term
Hypertonic
Definition
concentration is higher on this side than other side
Term
plasmolysis
Definition
loss of water by osmosis
Term
Hyperthemophiles (extreme thermophiles)
Definition
These are found in volcanoes. One species can grow at 121°C (boiling water is 100°C). These are members of Domain Archaea.
Term
Mesophiles
Definition
Grow well at room temperature and at body temperature. Most human pathogens are mesophiles. Some can divide every 20 minutes.
Term
Psychrotrophs
Definition
Grow at slightly warmer temperatures than cold-loving ones. These microbes can grow better than most other microbes at near freezing temperatures and can grow well at room temperature. These microbes are responsible for spoiling food in the refrigerator.
Term
pH
Definition
refers to the concentration of H+ in a solution.
Term
High pH (pH > 7) refers to: (2 names)
Definition
a basic solution (alkaline).
Term
Low pH (pH < 7) refers to
Definition
an acidic solution.
Term
Buffer
Definition
solution that resists changes in pH
Term
Acidophiles
Definition
microorganisms that grow at low pH; very few bacteria; yeasts and fungi can grow and spoil at pH 5-6
Term
Osmotic pressure
Definition
pressure caused by differences in solution concentrations across a selectively permeable membrane
Term
Isotonic
Definition
concentration same on both sides
Term
Hypotonic
Definition
concentration is less on this side than other side
Term
Hypertonic
Definition
concentration is higher on this side than other side
Term
plasmolysis
Definition
loss of water by osmosis
Term
halophiles
Definition
grow in salty solutions
Term
Obligate halophiles
Definition
require salt for growth.
Term
facultative halophiles
Definition
don't require salty solutions for growth but can tolerate them.
Term
heterotrophs
Definition
get carbon from organic materials (eg, humans)
Term
autotrophs
Definition
get carbon from "fixing" CO2 gas; there are 2 types of autotrophs
Term
photoautotrophs
Definition
get energy from light, and carbon from CO2 gas
Term
chemoautotrophs
Definition
Get energy from inorganic materials such as hydrogen sulfide, sulfur, ammonia, nitrate, hydrogen gas, ferrous iron, etc.). Get carbon from CO2 gas.
Term
Chemoheterotrophs
Definition
Get energy and carbon from organic materials. We (humans) are __________s.
Term
Important chemicals needed
Definition
carbon, nitrogen, sulfur, phosphorus
Term
nitrogen is used for...
Definition
is used to build proteins, nucleic acids.
Term
nitrogen is gotten by...
Definition
Most organisms that we are familiar with gain ____ from other organisms (digestion, decomposition); some get it from ammonium or nitrate. Others get it from atmosphere, photosynthesis by cyanobacteria..
Term
NITROGEN is necessary for...
Definition
all MICROORGANISMS require a source of (not s, p, c, or o)...
Term
Phosphorus is necessary for...
Definition
all MICROORGANISMS require a source of (not s, n, c, or o)...
Term
Sulfur is necessary for...
Definition
all MICROORGANISMS require a source of (not p, n, c, or o)...
Term
Oxygen is necessary for...
Definition
only SOME microoganisms need this, which is thought to contribute to aging...
Term
sulfur is used for...
Definition
proteins and vitamins; also chemoautotrophs use this for energy etc.
Term
Calcium, potassium, and magnesium are used for
Definition
...are used for a variety of purposes. They can be used for signaling or can be used as cofactors for enzymes. Remember that enzymes are biological catalysts and are used to assemble organic compounds (nucleic acids, proteins) and break down materials for energy. Enzymes often require cofactors to function properly.
Term
cofactors
Definition
A substance, such as a metallic ion or another enzyme, that must be associated with an enzyme for the enzyme to function.
Term
Trace elements (copper, iron, zinc, molybedum) are useful for...are gotten by...
Definition
are useful as enzyme cofactors. These are often found in tap water, so they don’t have to be added to bacterial growth media.
Term
Organic growth factors (vitamins**, amino acids, purines, pyrimidines). Used for ...
Definition
These are the building blocks used to assemble proteins and nucleic acids. Some microorganisms can assemble these from scratch, but many need to get these from another source in order to grow. (the first item in the parenthesis list is a thing that are often enzyme cofactors).
Term
we require ... for respiration, energy generation in mitochondria
Definition
we require oxygen for...
Term
reactive ----- species are ----
Definition
oxygen ... toxic
Term
list of the reactive oxygen species
Definition
Singlet oxygen (1O2-) Superoxide (O2-) Peroxide (O22-) Hydroxyl radical (OH?) Ozone (O3)
Term
oxidizing agents damage what? and the damage does what?
Definition
damage nucleic acids, fatty acids, etc. Damage to DNA produces mutations, phospholipids damages plasma membrane.
Term
oxidizing agents are used usefully by
Definition
phagocytes
Term
phagocytes (are)
Definition
(name for) macrophages of the immune system
Term
SOD
Definition
Superoxide dismutase
Term
Superoxide dismutase
Definition
neutralizes superoxide and produces hydrogen peroxide... O2- + O2- + 2H+ -> H2O2 + O2
Term
Catalase
Definition
Converts hydrogen peroxide to water and oxygen gas. 2H2O2 -> 2H2O + O2
Term
obligate aerobes
Definition
require oxygen for growth
Term
facultative anaerobes (define, give example)
Definition
can use oxygen when present, but grow ok (but less) without oxygen. Examples: yeast, E.coli;
Term
All oxygen-using microbes need these enzymes
Definition
catalase and superoxide dismutase
Term
obligate anaerobes (define, give example)
Definition
cannot survive in oxygen, must have non-oxygen environ. Example is clostridium.
Term
Aerotolerant anaerobes (define, give example)
Definition
Cannot use oxygen but are tolerant. An example includes Lactobacillus, a microorganism used to make yogurt and cheese. Have superoxide dismutase, no catalase.
Term
Microaerophiles
Definition
These do require oxygen, but at a much lower concentration than is present in the atmosphere. These microorganisms probably produce less superoxide dismutase and catalase.
Term
culture media (define, explain)
Definition
artificial growth environment for microorganisms is called ---, and can be liquid or solid; it must be sterilized.
Term
Liquid culture media (explain)
Definition
define: ---- is sometimes called broth, and you can mix agar with it to make it non----
Term
agar
Definition
polysaccharide used to make liquid culture media into a solid media. Most bacteria can't metabolize it, and it melts near 100C but remains liquid near 40C; it can be incubated near 100C, and there are many types.
Term
chemically defined media
Definition
the exact composition of this media is known; Used to grow chemoautotrophs and photoautotrophs, or this medium can be used to test the effect of a specific component (vitamin) on the rate of growth.
Term
complex media
Definition
The exact composition of the medium is not known. This is used in routine lab work for growing chemoheterotrophs. This type of media is made from extracts of plants, meat, and yeast to provide vitamins and organic growth factors. It also contains digested proteins (peptones) to provide carbon, energy, etc.
Term
Liquid complex media is called
Definition
*nutrient* broth,
Term
solid complex media is called
Definition
*nutrient* agar.
Term
Selective media (what is it; example)
Definition
This type of media is helpful for studying disease causing microorganisms because it suppresses the growth of unwanted microorganisms and allows for the desired microorganism. An example is bismuth sulfite agar, which prevents the growth of most Gram positive and intestinal Gram negative organisms, but allows the growth of certain Salmonella species. Sabouraud’s dextrose agar selects for fungi because it has a low pH.
Term
Plaque method
Definition
Growth of bacteriophages on solid media. This is typically done by mixing bacteria, bacteriophages, and melted agar, then pouring on the surface of an agar plate. The bacteria grow to make a “lawn,” a layer of bacteria on the surface of the plate. As the virus infects a bacterial cell it reproduces itself and infects neighboring bacteria. As more and more bacteria die, a clear area appears on the plate. These are called plaques. These plaques contain bacteriophages.
Term
plaques
Definition
clear areas on a lawn of bacteria, caused by bacteriophages
Term
PFU - determines the number of ---- or the concentration of viruses on a solid media
Definition
plaque forming units
Term
in vivo
Definition
viruses maintained in animals are called
Term
three ways viruses are maintained
Definition
in vivo, in embryonated eggs, in cell culture
Term
CPE(cytopathic effect)
Definition
when animal cell's biological properties change thanks to virus infections (eg, a monolayer on a surface becomes rounded or piled up)
Term
transformed
Definition
cells affected by the CPE are said to be...
Term
primary cell lines
Definition
cells or tissue slices derived from tissue; die after a few generations
Term
diploid cell lines
Definition
derived from human embryos, used to culture human viruses
Term
continuous cell lines
Definition
transformed tissue cultures with cancerlike properties; maintained indefinitely; produce viral particles indefinitely
Term
binary fission
Definition
bacteria reproduction by splitting via invagination.
Term
methods of cell reproduction
Definition
binary fission, budding, produce chains of conidiospores, fragmenting
Term
four stages of bacterial growth
Definition
lag phase, log phase, stationary phase, death phase
Term
Lag phase
Definition
A period of time where little cell division occurs. It is a period of intense metabolic activity, where enzymes and molecules are synthesized.
Term
Log phase
Definition
A period of time where cells divide rapidly. This is a time when the generation time is the smallest. This phase of growth is where many cellular products are synthesized, including the cell wall. Thus Gram positive cells are susceptible to penicillin during this kind of growth.
Term
Stationary phase
Definition
A period where the growth rate slows and the resources (nutrients) in the culture medium are exhausted. Here waste products accumulate, and changes of pH slow growth. During this phase the rate of cell growth and the rate of cell death are roughly equal. The metabolic activity of cells also slows down.
Term
Death Phase
Definition
A period where the rate of death exceeds the rate of growth. The population may die off completely or very few cells will remain. The cells in the solution may look sick. Involution occurs.
Term
Involution
Definition
when dying, cell morphologies can change dramatically
Term
A spectrophotometer
Definition
is used to measure turbidity; used to estimate number of bacteria in a cell, not measure accurately. Two types of measurement are transmission and absorbance.
Term
is called sterilization.
Definition
To remove all traces of life, for example from a piece of surgical equipment or a solution; would refer to the removal of endospores, as well.
Term
The sterilizing agent is called
Definition
the sterilant.
Term
Commercial sterilization
Definition
a term used to describe the process of killing Clostridium endospores in canned foods. Destruction of all life by further heating would damage the quality of the food.
Term
Disinfection, disinfectants, refers to
Definition
the removal of all harmful microorganisms. usually removes growing (vegetative) cells. It does not destroy endospores. Surfaces are ---- using chemicals called --- , UV radiation, boiling water, or steam.
Term
antisepsis.
Definition
When you try to remove pathogens from the surface of living tissue, the process is called ---;
Term
A chemical used to remove the pathogens is called an
Definition
antiseptic
Term
Sepsis, septic
Definition
(1) is a term that indicated bacterial contamination. Blood can become (2).
Term
Asepsis
Definition
refers to the absence of bacteria.
Term
degerming.
Definition
Mechanically removing (scrubbing) microorganisms from a limited area, such as the surface of the skin prior to an injection is called
Term
Sanitation
Definition
refers a treatment that lowers microbial counts to safe levels. When you put your dishes in the dishwasher they are cleaned and ----.
Term
A chemical that kills microbes is a
Definition
germicide (biocides).
Term
A chemical that kills fungi is a
Definition
fungicide.
Term
A chemical or technique that slows the growth of bacteria is a
Definition
bacteriostatic agent.
Term
microbes die at a ---- rate
Definition
microbes --- at a constant rate (ie they --- by a fixed percent per minute)
Term
Things that afffect death of microbes
Definition
number of them (more means longer); environment (antimicrobials work better in warm solutions); exposure time (needs to be longer if more microbes or if have endospores etc)
Term
porins
Definition
protein pores in outer membrane.
Term
prions
Definition
infective proteins, eg mad cow disease.
Term
Thermal death point (TDP)
Definition
Lowest temperature where all microorganisms can be killed in 10 minutes.
Term
Thermal death time (TDT)
Definition
The minimum length of time for all bacteria of that species to die at a given temperature. This time changes for different temperatures.
Term
Decimal reduction rate (DRT)
Definition
The time, in minutes, in which 90% of the bacteria in a sample are killed.
Term
An autoclave
Definition
uses steam under pressure to increase the temperature for sterilization.
Term
Pasteurization
Definition
This process uses mild heating to kill pathogenic microbes and lower the total number of microbes, but not affect the taste of the food.
Term
dry heat -
Definition
used to sterilize equipment, such as with a bunsen burner (flaming).
Term
hot air sterilization
Definition
requires placing an item in an oven (eg, 170C for 2 hrs)
Term
Refrigeration as microbe control is
Definition
bacteriostatic form of controlling microbes with temperature.
Term
desiccation
Definition
absence of water is bacteriostatic; this is called...
Term
microwaves
Definition
type of radiation that doesn't harm microorganisms.
Term
ionizing radiation
Definition
high energy radiation (gamma, x) hydroxyl radicals form; sterilize certain foods and medical supplies;
Term
nonionizing radiation
Definition
lower energy, such as UV; damages DNA; used to disinfect hospital rooms and medical equipment.
Term
Use-dilution test
Definition
Metal rings are coated with three microbes, usually Salmonella choleraesius, Staphylococcus aureus, and Pseudomonas aeruginosa. Different version of this test can examine the effectiveness of disinfectants on endospores, Mycobacteria, and fungi. These rings are then placed in serial dilutions of a solution of the disinfectant that is to be tested (10 minutes at 20°C). Then the rings are placed in growth media. If the culture grows, that particular concentration of the disinfectant is ineffective. This is a --- test.
Term
Disk-diffusion method
Definition
in the --- method, A filter paper disk is saturated with a disinfectant (or an antibiotic) and is place on an agar plate containing a lawn of a particular microorganism. If the disinfectant works, a clear zone will form around the disk.
Term
phenol, eg O-phenylphenol
Definition
The action of these compounds (1) is to disrupt the plasma membranes of microbes, and the cell walls of mycobacteria. They are used to disinfect complex substances that contain organic compounds (i.e. pus, feces). A good example is (2), found in Lysol.
Term
bisphenols
Definition
composed of two phenolic groups.
Term
example of bisphenols
Definition
triclosan
Term
biguanides
Definition
disinfectants used on skin and mucous membranes, such as chloroheidine which blocks lipid synthesis in membranes of microbes
Term
halogens
Definition
chlorine and iodine - iodine blocks protien synth of plasma membr. chlorine makes hypochlorous acid in water which oxidizes cellualr components.
Term
alcohols
Definition
eg isopropanol and ethanol - kill veg cells, not endosp or nonenv viruses; denatures proteins and dissolves lipids; degerms.
Term
heavy metals
Definition
germicidal effect by oligodynamic action, denature proteins.
Term
Quaternary Ammonium Compounds (Quats)
Definition
These are cationic detergents, meaning that they contain a positively charged ion. This cation is related to the ammonium ion (NH4+). These destroy Gram positive cells, fungi, amoeba, and enveloped viruses effectively. These LIKELY DISRUPT THE PLASMA MEMBRANE. An example is Zephiran (benz-alkonium chloride). These are not effective against endospores and mycobacteria.
Term
Aldehydes-
Definition
These are probably some of the best antimicrobials. Examples are formaldehyde and gluteraldehyde. These function to inactivate proteins in bacteria and viruses.
Term
Peroxygens
Definition
These contain reactive oxygen species that oxidize cellular components. one of these can be used to destroy bacteria faster than the bacterial cell’s superoxide dismutase and catalase can inactivate it.
Term
Factors influencing growth of microorganisms
Definition
Physical and Chemical factors
Term
Chemical factors
Definition
carbon, nitrogen, sulfur, and trace inorganic and organic growth factors
Term
correct temperature, pH, and osmotic pressure
Definition
Physical factors
Term
Psychrophiles, grow at ?
Definition
cold-loving microorganisms.
Term
Thermophiles
Definition
Heat loving microorganisms, generally above 40degC
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