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Microbiology chapter 1, 3, 4, 5


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Study organisms too small to be seen with the naked eye.
Anthony Van Leeuwenhoek
The first to observe bacteria
Louis Pasteur
Father of modern microbiology, refuted spontaneous generation by a series of experiments
Role of microorganisms
Production of nitrogen and O2, decomposers, food and alcohol production, bioremediation
The use of living organisms to degrade environmental pollutants
Genetic engineering
Introduction of genes from one organism into an unrelated organism to confer new properties on that organism (the manipulation of genes)
Gene therapy
Viruses being studied as means of delivering genes into humans to correct conditions such as cystic fibrosis, heart disease and cancer
Three major groups of living organisms:
bacteria, Archaea, Eucarya
Single-celled Prokaryotes with no nucleus
-- genetic information stored in DNA
-- specific shapes have mostly cylindrical or spherical
-- rigid cell walls
-- multiply by binary fission
Single-celled Prokaryotes with no nucleus
-- multiply by binary fission
-- rigid cell walls
-- ability to grow in extreme environments: extreme hot/cold, presence of large amounts of salt
All members of the living world except Prokaryotes
-- consist of eukaryotic cells
-- algae, fungi, protozoa
Diverse group of eukaryotes
-- single/multicellular
-- many different shapes and sizes
-- contain chloroplasts
-- derive energy from sunlight
-- found near water surfaces
-- rigid cell wall
Diverse group of eukaryotes
-- singular/multicellular
-- -- single -- East
-- -- Multi -- moles
-- gain energy from organic materials
-- mostly online
Diverse group of microscopic, single-celled organisms
-- live in both water and on land
-- complex and larger than Prokaryotes
-- no rigid cell wall
-- major feature of classification is means of locomotion
Binomial system of classification
Two word naming system:
-- first word -- Genus (always capitalized)
-- second word -- species in (not capitalized)
-- both always italicized or underlined
-- members of the same species may vary resulting in strain designations
Non-living: viruses, viroids, prions
Consist of a piece of nucleic acid surrounded by a protein current
-- need to reproduce copies of themselves in order to exist
-- can only multiply inside living host cells
-- inactive outside of the host
-- considered obligate intracellular parasites
-- frequently kill the cells in which they multiply
-- can exist harmonious within the host cell without causing obvious ill effects
Simpler than viruses
-- single, short piece of nucleic acid, specifically RNA, without a protective coat
-- much smaller than viruses
-- can only reproduce inside cells
-- cause a number of plant diseases
Unusual agents responsible for at least seven neurodegenerative diseases in humans/animals (always fatal)
-- scrapie in shee and shep
-- mad cow disease
**consist of only one protein without any nucleic acid
Important tools for studying microorganisms
-- uses visible light for observing objects
Ocular lens times objective lens equal total magnification
-- typically 4x, 10x, 40x, 100x
Clear separation of two objects are close together
Resolving power
The minimum distance between two objects when those objects can still be observed as separate entities
-- determines how much detail can actually be seen
Reflects the number of visible shades in a specimen
-- high contrast being two shades, black and why
Scanning electron microscope
-- used for observing surface details of sales
Transmission electron microscope
-- used to observe fine details of cell structure
-- require elaborate specimen preparation
-- 1 of two most common shapes of bacteria
-- 1 of two most common shapes of bacteria
Rod-shaped bacterium, very short
Short curved Rod's
Curved Rod long enough to form spirals
Long helical cell with a flexible cell wall
-- unique mechanism for motility
Bacteria that characteristically vary in shape
-- Pleo -- many
-- Morphic -- shape
Binary fission
After a cell has increased in size and doubled all of its parts, it divides one cell divides into two, those two divide to become four and those four become eight and so on
Cell divides in one plane
Cell divides into or more planes perpendicular to one another
Cell divide in several planes at random
Cell wall
Rigid barrier that functions as a tight corset to keep the cells contents from bursting out
A macromolecule found only in bacteria that provides rigidity to the cell wall
Selectively permeable
Membrane that allows some but not other molecules to pass through freely
Simple diffusion
Movement of molecules or ions for a region of high concentration to a region of low concentration
-- does not involve transport proteins
Viscous fluid within a cell
Region of a prokaryote cell containing the DNA
Long protein structures responsible for most types of bacterial motility
Enable attachment of cells to specific surfaces
-- shorter and thinner than flagella
Glycocalyx that is distinct and gelatin this
-- sometimes correlated with organisms ability to cause disease
Deoxyribonucleic acid
Small extrachromosomal circular DNA molecule that replicates independently of the chromosome
-- often codes for ABT resistance
Structure that facilitates the joining of amino acids during the process of translation
-- composed of protein and ribosomal RNA
Light microscope
Microscope that uses visible light to observe objects
Differential staining
Type of staining procedure used to distinguish one group of bacteria from another by taking advantage of the fact that certain bacteria have distinctly different chemical structures in some of their components
Gram stain
Staining technique that divides bacteria into one of two groups on basis of color
-- gram-positive -- purple
-- gram-negative -- pink/red
Acid-fast stain
A procedure used to stain certain microorganisms
-- particularly Mycobacterium (do not readily take up dye)
Endoplasmic reticulum
Organelle of the eukaryotes where the macromolecules destined for the external environment of other organelles are synthesized
Smooth reticulum
Organelle of eukaryotic cells that is the site of lipid synthesis and degradation of calcium storage
Wrath reticulum
Organelle where proteins destined for location other than the cytoplasm are synthesized
Membrane-bound structure in eukaryotic cell that contains powerful degradative enzymes
Membrane-bound organelle in a eukaryotic cell that contains chromosomes and the nucleolus
Process by which cells take up particles by enclosing them in a vesicle pinched off from the cell membrane
Process by which eukaryotic cells expel material
-- membrane-bound vesicles inside the cell fuse with the plasma membrane, releasing their contents to the external medium
Most common form of endocytosis and animal cells
-- the and decided vesicle fuses with an endospore, which then fuses with a lysosome
Plasma membrane
Phospholipid bilayer embedded with proteins
Generation -- doubling time
The time it takes for a population to double in number
Polysaccharide encased community of microorganisms
Pure culture
A population of organisms descended from a single cell and therefore separated from all other species
Liquid media
Broth like
Solid media
Liquid with agar added
A polysaccharide extracted from Marine algae, is used to solidify a liquid culture medium
Streak plate method
Simplest and most commonly used technique for isolating bacteria. A sterilized inoculating loop is dipped into a solution containing the organism of interest as lightly drawn several times across agar plate creating a set of parallel streaks covering approximately one third of the plate. The loop is then sterilized and a new series of parallel streaks are made across the at an angle to the previous ones, covering another third of the plate. The loop is sterilized again and another set of parallel streaks are made dragging into a third area some of the organisms that had been moved into the second section by the third set of streaks cells should be separated enough so that distinct well isolated colonies will form
A mass of cells all descended from the original one. About one million cells are required for a colony to be easily visible to the naked eye
Organisms usually found in such environments as the Arctic and Antarctic regions
-- optimum conditions between -5°C and 15°C
An important cause of food spoilage
-- have a temperature optimum between 20°C and 30°C, but grow well at lower temperatures
Includes E. coli and most other common bacteria
-- optimum temperature between 25°C and 45°C
Have an optimum temperature between 45°C and 70°C
-- these organisms commonly occur in Hot Springs and compost heaps
-- they are also found in artificially created thermal environments such as water heaters and nuclear power plant cooling towers
Have an optimum growth temperature of 70°C or greater
-- these are usually members of the Archaea
Obligate Aerobe
Have an absolute or obligor requirement for oxygen
-- use oxygen to transform energy and the process of aerobic respiration
-- includes micrococcus species, gram-positive Cocci that are common in the environment
Obligate Anaerobe
Cannot multiply in the presence of O2; in fact they are often killed
-- transform energy by fermentation or anaerobic respiration
-- include members of the genus bacteroides, Clostridium botulinum
Facultative Anaerobe
Grow better if O2 is present, but can also grow without it
-- the organism is flexible in regards to O2 requirements
-- use aerobic respiration if O2 is available
-- fermentation or anaerobic respiration and absence of O2
-- growth more rapid when O2 is present
Bacteria the typically require O2 concentrations less than what is achieved in a candle jar
-- these bacteria are often incubated in a gas tight jar with special disposable packets containing chemicals that react to generate hydrogen and carbon dioxide
Aerotolerant Anaerobe
Indifferent to O2
-- can grow in its presence that do not use it to transform energy
-- also called obligate fermenters
-- example is Streptococcus pyogenes which cause strep throat
Bacteria that can live and multiply within the range of pH 5 (acidic) to pH 8 (basic) and have a pH optimum near neutral (pH7)
Grow optimally at a pH below 5.5
Grow optimally at a pH about 8.8
-- often live in alkaline lakes and soils
Uses inorganic carbon in the form of carbon dioxide
-- plays a critical role in the cycling of carbon and the environments because they can convert inorganic carbon 10 organic form
-- process of carbon fixation
Prokaryotes they use organic carbon
Organisms that harvest the energy of sunlight
-- these include plants, algae and photosynthetic bacteria
Organisms that obtain energy by metabolizing chemical compounds
Differential media
Bacteriological medium that contains an ingredient which can be changed by certain bacteria in a recognizable way
-- used to differentiate organism's based on their metabolic traits
Microorganisms that display a wide spectrum in their growth factor requirements set chest Neisseria that require many growth factors
Blood agar
A rich medium commonly used in clinical laboratories that contains red blood cells, which supply variety of nutrients including hemin, in addition to other ingredients
Organisms requiring increased CO2 along with approximately 15% O2
-- one of the simplest ways to provide this atmosphere is to incubate them in a closed candle jar
The cells may be killed if they are exposed to O2 for even a short time
Idea that there are specific compartments in eukaryotic cells in each perform specific function
The process of destroying or removing all microorganisms and viruses three physical or chemical means
-- filtration
-- heat
-- chemicals
-- irradiation
A treatment, usually brief heating, used to reduce the number of spoilage organisms and to kill disease causing microbes
The process that eliminates most or all pathogens on or in a material
*SOME microbes may persist
Disinfect and that is non-toxic enough to be used on scan
A chemical used to destroy many microorganisms and virus this
-- biocides
-- used on inanimate objects
The process of delaying spoilage of foods or other perishable products
-- inhibiting the growth of microorganisms
Single most important step in preventing the speed of many infections
-- simple -- soap and H2O
Nosocomial infections
Hospital acquired infections
Selection of anti-microbial procedure
Determined by the microbial population president on or in the product
Bacterial endospores
Most resistant forms of life
-- only extreme heat or chemical treatment ensure complete destruction
Protozoan cysts and oocytes
Disinfectant resistant forums excreted in PCs of infected animals and humans
-- causes diarrheal disease if ingested
-- readily destroyed about boiling
Mycobacterium species
Resistant to many chemical treatments
-- stronger or more toxic disinfectants must be used
**example: M. bacterium (TB)
Pseudomonas species
Not only resistant to some chemical disinfectants, in some cases actually grow in them
**importance in hospital setting
Naked viruses
Resistant to disinfectants
-- lack lipid envelope
-- envelope the virus this (HIV) tend to be sensitive to heat and chemical disinfectants
Decimal reduction time
D. value
-- time required for killing 90% of a population of bacteria under specific conditions
-- commercial canning industry
Moist heat
-- boiling for five minutes destroys most microorganisms and viruses
Pressurized steam
-- typical treatment is 121°C/15 psi for 15 minutes this
Filter retains microbes while leading the suspending fluid or air pass through small holes
Filtration of fluids
Various pore sizes available
-- used to produce beer/wine/sterilized sound heat sensitive medications
Filtration of Ayer
HEPA filters are used to remove microbes that have a diameter greater than 0.3nm
Dry heat
Not as efficient as wet heat and killing microorganisms
-- requires longer times and higher temperatures
-- incineration, dry heat oven
Way it has to rising commercial food products
-- treatments of 130,000 psi is thought to destroy microorganisms by denaturing proteins altering the permeability of the cell
-- products retained flavor/color
Substantially reduces microbial population that meet acceptable health standards
Treatment used to decrease the number of microbes in an area
-- usually the scan
Tree menus to reduce the number pathogens to a level considered safe to handle
-- handwashing, heat, disinfectants
Chemicals as control
-- sterilants
-- high level disinfectants
-- intermediate level disinfectants
-- low level disinfectants
Can destroy all microorganisms including endospores and viruses
-- 6 to 10 hour treatment to kill endospores
example: scalpels
High level disinfectants
Destroy all viruses and vegetative microorganism
** DO NOT readily kill endospores
example: endoscopes
Intermediate level disinfectants
Destroys all vegetative bacteria including mycobacteria, fungi, most but not all viruses
** DO NOT kill endospores
example: stethoscopes
Low-level disinfectants
Detroit fungi, vegetative bacteria EXCEPT mycobacteria an enveloped viruses
--DO NOT kill endospores, don't readily destroyed naked viruses
Piece of protein that causes infection
60 to 80% isopropyl or evil alcohol rapidly kill vegetative bacteria and fungi
evaporates fast
Unstable form of O2 that is a powerful oxidizing agent
Organic acids
Sometimes added to foods such as bread, cheese, juice to prevent microbial growth
-- Benzoic, Sorbic, Proprionic
-- alter cell membrane function
Removing water from food
Sales a hearing to one another following division from characteristic arrangements such as chains, packets, clusters
Cell wall contains a relatively thick layer of peptidoglycan
-- Teichoic acids stick out of the peptidoglycan later
Cell wall has a relatively thin layer of peptidoglycan sandwiched between the cytoplasmic membrane and an outer membrane
Prevents peptidoglycan synthesis
Use the energy released during the dead predation of organic compounds to generate ATP
take up of debris by protozoa and phagocytes
-- phagosome fuses with lysosome where material is digested
Phospolipid Bilayer
barrier between the cytoplasm and the outside environment
Basic dyes
Carry a positive charge
-- are more commonly used for staining
-- stained the negatively charged components of sales, including nucleic acid and many proteins
-- methylene blue, Crystal violet, saffranin and, Malachite green
Acidic dye
Carry and negative charge
-- sometimes used to stain battlegrounds against which colorless sales can be seen
Zone of Complete Clearing
beta hemolysis
Zone of Green Clearing
alpha hemolysis

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