Microbiology Exam 1
What is Spontaneous Generation?
an early belief that some forms of life could arise from vital forces present in nonliving or decoposing matter. (ex flies from manure, maggots/flies)
What type of experiment was done to disprove spontaneous generation?
Who disproved spontaneous generation?
What is the theory of Biogenesis?
The idea that living things can only arise from other living things.
Who proved the Theory of Biogenesis?
Who had the first demonstration of bacterial disease?
Robert Koch in 1876
Who was Ignaz Semmelweis?
Austrian physician that realized that disease was being carried from the autopsy room to maternity ward. He also promoted hand washing. He look at death of mothers caused by puerperal fever or childbirth fever associated with childbirth.
What did Joseph Lister do?
An English surgeon who promoted heat and chemical sterilization. He introduced the aseptic technique to reduce microbes in medical settings and prevent wound infections.
Who was Florence Nightingale?
Founder of modern nursing and introduced antiseptic technique into nursing practice.
What did John Snow discover?
Figured out that the London Cholera epidemic in 1854 was caused from infected water pump.
What did Edward Jenner do?
Used cowpox to vaccinate for smallpox in 1796.
Hans Christian Gram
introduced gram stain, 1884.
1892, discovered viruses
What did the Electron Microscope do?
Allowed Virology to become a major discipline by 1950s.
What is Taxonomy?
Organizing, classifying, and naming living things.
Who started Taxonomy?
Carl Von Linne
What is taxonomy concerned with?
Classification (arragement of organisms into groups)
Nomenclature (assigning names)
Identification (determining and reording traits of organisms for placement into taxonomic schemes)
What is a Taxon?
a group of organisms of any rank that is sufficiently distinct to be worthy of a name. (plural=taxa)
What is Rank?
a category or level in a hierarchical classification.
What is the taxonomy list?
Kingdom, Phylum, Class, Order, Family, genus, species.
(King Phillip came over for great sex)
the delimiting order and ranking of taxa
is the determination of the taxonomic identity of an organism
came up with the tree to classify different types of microbes
is the process of assigning names to the different taxonomic ranks of each species
Binomial System of Nomenclature
a system of naming requiring that the scientific name will always consist of a combination of the genus name and the specific epithet.
How is Specific names of species written?
Genus name is capitalied
Species is lowercase
both are italicized when typed or underlined when written
natural relatedness between groups of organisms
all new species originate from preexisting species.
Closely relatedorganisms have similar features because they evolved from common ancestral forms.
Evolution usually prgresses toward greater complexity.
What are the 6 I's in studying microorganisms?
How do you incubate a microorganism?
In the same condition you found it in.
What is Inoculation?
Producing a culture.
What are common specimens for inoculation?
body fluids, tissues, foods, waters or soil.
Selection of media with specialized functions can improve later steps of isolation and identification. Some microbes may require a live organism as the inoculation medium (animal or egg).
growing the inoculum under the right conditions
How long do you incubate for?
setting the optimum temperature and gas cotent promotes multiplication of the microbes over a period of hours, days and even weeks.
What is isolation?
separating one species from another. The macroscopic product of incubating the inoculum.
What type of culture is ideal?
a pure culture.
What is a colony?
A discrete mound of cells of one species formed from a single original cell.
What are the different ways to isolate a species?
Streak plate method, loop dilution (pour plate), spread plate.
What are the conditions for media preparation?
Asepsis and Aseptic technique
What is Asepsis?
the absence of contamination by unwanted organisms
What is Aseptic technique?
Sterile technique. Means that sterile media and inoculating tools must be used.
What are the 3 categories or media classification?
Physical state (medium's normal consistency), chemical composition (type of chemicals medium contains), functional type (purpose of medium)
What are the 4 types of physical states of medium?
3. Solid (can be converted to liquid)
4. Solid (cannot be liquefied)
What are the types of chemical compositions?
1. Synthetic (chemically defined)
2. Nonsynthetic (not chemically defined)
Types of Function Types for media classification?
1. General purpose
2. Enriched- extra nutrients
3. Selective- (only certain things will grow)
5 Anaerobic growth-grows only organisms with no O2
Example of liquid media
Broths and milk
example of semisolid media
sulfur indole motility
has a stab zone that shows if media moves. Cloudy/ turbitity is how you can tell if it has motility.
Examples of Solid Media
TSA- was liquid and will liquify
rice grains- never in a liquid state
also can use cooked meat
What is synthetic media?
chemically defined, man made
what is non-synthetic media (complex)?
non chemically define.
example tsa- made from seaweed
What is enriched media?
For fastidious bacteria (hard to grow bacteria)
example- sheep blood agar, enriched TSA with blood
What is selective media?
only grows certain types bacteria.
example- MSA mannitol salt agar- will only grow staph species because of salt. (salt will kill other bacteria)
What does Eosin Methylene Blue (EMB) Agar grow and what type of media is it?
It is a selective media that will only grow E Coli because of its antibacterial properties in the dye.
What does Mac Conkey Agar grow and what type of media is it?
It is a selective media that grows intestinal parasites.
What is differential media?
Media that produces some sort of change.
example- it causes a change in ph or color.
What is Thioglycollate broth?
Media that looks at oxygen requirement.
examples- Facultative Anaerobe, Aerobe, Obligate Anaerobe.
What is fermentation media?
Uses Durham Fermentation tubes and Phenol red to show PH and to see if it breaks down sugar. It also shows gas.
What is an Aerobe?
What is an Anaerobe?
Aerobe requires oxygen.
What is facultative anaerobe?
Means it can do with or without oxygen.
What is obligate anaerobe?
means it can not live with oxygen.
What is subculturing?
The process of further isolation, to prodcue a pure culture.
Where do contaminated colonies usually form?
They hang out on the edge of the plate.
What is inspection?
4th step in culturing microorganism. It is macroscopic observation of the oclonies and microscopic observations (staining smears).
What is identification?
To identify the species and/or strain. The 5th step in methods for culturing microorganism.
What is an autoclave?
What is an incinerator/inceneration?
Autoclave is used to sterilize instruments with heat.
Incinerator is machine that burns to sterilize or destroy.
What is magnification?
the ability to enlarge objects.
What is resolution?
ability to show detail.
What is maginification in microscopes a result from?
an interaction between visible light waves and the curvature of a lens.
The extent of enlargement is the what?
What were the 4 early types of microscopes?
1. Martin pocket microscope
2 Nairne chest microscope
3.Nuremberg "toy" microscope
4. Solar Microscope by Dolland
What is the total magnification?
is a product of the separate magnifying powers of the two lenses.
objective power x ocular power= total magnification.
What is Resolution?
The capacity to distinguish or separate two adjacent objects. It depends on the wavelength of light that forms the image along with characteristics of the objectives.
(example hands/balls, flagellar or legs)
When you have a shorter wave length, can you see the resolution and details better? true or false
Shorter wave lengths can?
Enter the small spaces and produce a more detailed image that is recognizable as a flea.
What is a Transmission Electron Microscope?
Transmit the electrons through the specimen.
Darker areas indicate more transparetn, less dense parts.
What is a scanning electron microscope?
provides a detailed three dimensional view. You can see surface.
Which microscope has to use a dead organism and can't see color?
Scanning Electron Microscope
Toxoplasma gondii is what type or microorganism?
Protozoan that causes toxoplasmosis
What type of preparation allows you to see live, motile organisms?
Wet mounts and hanging drop mounts.
What type of preparation is temporary?
wet mounts and hanging drop mounts.
What does wet mount and hanging drop mount preparations allow you to examine?
The characteristics of live cells, the size, shape, motility and arrangement.
What is a fixed mount?
a permanent prepared slide that is a smear that is stained using dyes for permit visulaization of cells or cell parts.
What type of slide is a hanging drop slide?
a depression slide
Do you need to use a slide cover with smear that is stained?
How do you made a fixed or stained smear?
Using heat fixation
What are heat fixations 2 accomplishments?
fixes specimen to slide and kills specimen.
What type of charge does basic have?
what type of charge does acidic have?
What are the advantages of negative or background staining?
size is more acccurate (because head is not suded which causes shrinking)
Better for spirochetes since they don't stain well (with a positive stain)
It is simpler to do (since there is not smear prep and no heat fixation)
If we have acidic and basic dyes to stain bacterial cells and if bacterial cells are negatively charged, which dye is going to do a better job?
basic or positively charged stains.
All bacteria cells are _________ charged?
What are the 2 subtypes of positive stain?
Simple stains and differential stains
What is a simple stain?
uses one type of stain.
example- Methylene blue, basic fuchsin or carbol fuchsin and crystal violet, malachite green and safranin.
What is a differential stain?
uses 2 dyes, primary and counterstain to differentiate between 2 cell tupes or cell parts.
Example- gram stain.
what are the steps for gram stains?
1. crystal violet, gram's iodine (mordant), alcohol, safranin
What is an example of acid-fast stain?
Mycobacterium tuberculosis and M. leprae and some spp. of Nocardia.
What is the purpose of acid fast stain?
hard to get into the cell wall and acid allows you to get into the cell wall and stain.
allow protection from phagocytes and has an outer gelatinous or slimy layer.
negatively stained background, positively stained cell and halo.
What is the purpose of a flagellar stain?
to visualize flagella with light microscope.
What is a flagellar stain considered?
What are halophiles?
a type of extremophile. They can live in high salt contents, higher than the ocean. example- dead sea and salt lake in Utah.
What is Glycocalyx?
Surface coating of Prokaryote
What are the 2 major groups of Appendages?
Motility (flagella and axial filaments (periplasmic flagella)) and Attachment or channels (fimbriae and pili)
What are the 3 parts of Flagella?
Filament (long, thin helical structure composed of protein flagellin)
Hook- curved sheath
Basal body- stack of rings firmly anchored in cell wall
How does a prokaryote flagella move?
rotates 360 degrees
What are the 4 types of flagellar arrangements?
amphitrichous- tails at each end
peritrichous- all over
What is periplasmic flagella?
internal flagella that is between the outer sheath and the cell wall peptidoglycan.
What 2 structures is perplasmic flagella between?
outer sheath and cell wall of peptidoglycan
What type of motion does perplasmic flagella produce?
motility by contracting and imparting twisting or flexing motion.
What are Fimbriae?
hair like bristles emerging from the cell surface
What is the Fimbriae made of, and what are their function?
made of proteinaceous material and adhesion to other cells and surfaces.
what is pili?
rigid tubular structure that joins bacterial cells together for partial DNA transfer called conjugation. (cell sex)
What is pili made of?
Where are pili found?
only in gram negative cells
What is the cell envelope?
covering outside of the cytoplasm, maintains cell integrity.
What are the 2 basic layers of the cell envelope?
cell wall and cell membrane
what type of cell wall is there in a positive gram stain bacteria?
thick cell wall of peptidoglycan and cell membrane.
what type of cell wall is there in a negative gram stain bacteria?
thin peptidoglyan layer and cell membrane.
How does the gram stain work?
It uses alcohol to wash away lipid layer.
What are the 2 types of Glycocalyx?
Slime layer and capsule
how is the slime layer organized?
loosely organized and attached
how is the capsule layer organized?
highly organaized and tightly attached.
what are the functions of Glycocalyx?
protects cells from dehydration and nutrient loss.
inhibits killing by white blood cells by phagocytosis
attachemnt- formation of biofilms.
what does the cell wall do?
determines cell shape, prevents lysis due to changing osmotic pressures.
what is peptidoglycan a primary component in?
how thick is the layer of peptidoglycan in a gram positivve cell wall?
what does a gram positive cell wall include?
teichoic acid and lipoteichoic acid
what is found on the outer layer for a gram negative cell wall?
what is found in the lipid portion of a gram negative cell wall?
endotoxin, which may be release during infections.
What may function as receptors and blocking immune response?
outer membrane (lipopolysaccharides (LPS))
What is porin?
proteins in upper layer of gram negative cell wall.
What do porins do?
regulate molecules entering and leaving cells.
What is important basis of bacterial classification and identification?
the gram stain.
What are 2 difference in gram negative and gram positive cells?
gram negative have LPS and contain endotoxcins and gram positive have teichoic and lipoteichoic acids to stimulate specific immune response (antigenicity) from the patient.
what is it called when a gram positive cell wall structure has a lipid mycolic acid?
What is the name of the organism that has no cell wall?
What is the cell wall stabilized by in Mycoplasma?
What does pleomorphic mean?
can change shape.
What is the phospholipid bilayer embedded with?
proteins-fluid mosaic model
what are the functions of the cell membrane?
providing site for energy reactions, nutrient processing and synthesis.
passage of nutrients into the cell and discharge of wastes.
cell membrane is selectively permeable
what is an aquaporins function?
water leaves through this
what is cytoplasm and what does it contain?
denses gelatinous solution of sugars, amino acids and salts. It is 70-80% waters and serves as solvent for materials used in cell functions.
What is mesosomes?
internal folds in cytoplasm.
What does mesosomes do?
increase the internal surgace area available for membrane activities. This is the internal surface of prokaryotic cell.
What does a Prokaryote have instead of a nucleus?
What is an endospore?
hard to kill cell that is formed when a bacteria feels threatened and environmental sources are depleted. It hoards food if there are environmental changes.
Prokaryote chromosome is what?
single circular, double stranded DNA molecule that has genetic informationrequired by a cell.
free small circular double stranded DNA, not essential to bacterial growth and metabolism. Used in genetic engineering.
What do ribosomes doe?
bacterial ribosomes are made of what?
60% ribosomal RNA and 40% protein
What are the 2 subunits of ribosomes?
large and small
How do the prokaryotic and eukaryotic ribosomes differ?
in the size and number of proteins.
What is the site of protein synthesis?
What are inclusions and granules?
a bacterial internal structure that serves as an intracellular storage body. They varie in size, number and content.
What are examples of endospores?
Clostridium, Bacillus and Sporosarcina
What is the 2 phase life cycle of an endospore?
Vegetative cell and the endospore.