Micro Lab Midterm Flashcards
A process in which vegetative microorganisms are destroyed on non-living objects and surfaces is known as:
Disinfection
The COMPLETE/TOTAL destruction or removal of all microorganisms (including viruses & endospores) is known as:
Sterilization
The following describe what term?
- the growth (multiplication) of microorganisms in normally sterile tissues
- decay, contamination, purification
- the presence of bacteria in blood that are actively multiplying
Sepsis
A medical term, any procedure that prevents the entrance of infectious agents into sterile tissue, thus preventing infection is called:
Asepsis
Practices used by microbiologists to exclude ALL organisms from contaminating media or contacting living tissues is called:
Aseptic techniques
Chemical agents (often dilute disinfectants), that can be safely applied, externally, to living tissues (skin, mucous membranes) to destroy or inhibit vegetative bacteria is known as:
Antiseptics
Define vegetative.
Actively growing
- Most numerous and most widely distributed organisms
- Microorganisms are found everywhere in nature
- While the environment where a microorganisms is normally found in presumably the environment to which it is best adapted
- They are not necessarily confined to those areas (environmental niches)
- Microorganisms found in and on you can be transferred easily to other environments
These characteristics describe:
Bacteria
The fine (microscopic) details of organisms, tissue and cells is called:
Ultrastructure
The ability of a lens, or lenses, to make an image larger; to have the power of causing objects to appear larger than they are. This is called:
Magnification
The ability to see the fine details of an image in clear sharp focus is called:
Resolution
A microscope consisting of only 1 lens, also called a “magnifying glass” is called:
Simple microscope
A microscope consisting of an objective lens and an ocular lens mounted in a draw tube and consists of 2 lenses. This is called:
Compound microscope
The lens in a compound microscope that you look through and which magnifies the image made by the objective lens; usually 10x and is also known as the eye piece. This is called:
Ocular lens
The lens in a compound microscope that does the initial magnification of the specimen on the microscope slide is called:
Objective lens
What are the 4 characteristics for morphology of bacteria?
- size
- shape
- cell arrangement
- Gram staining reaction
40x
Scanning
100x
Low power
400x
High power
1000x
Oil immersion
1 permanent shape of bacteria, due to its rigid external cell wall, (composed of the unique complex carbohydrate peptidoglycan) is called:
Monomorphic
Bacillus (Bacilli)
Rod shaped
Coccus (Cocci)
Sphere or round-shaped bacteria
Spiral
Helical or curved shaped
Vibrio
Comma- shaped bacteria
Spirochetes
Flexible “S”shaped
Spirillum
Rigid, cork-screwed shaped
Random arrangement
Single cells, no overall arrangement
Diplo arrangement
Pair of cells
Tetrad arrangement
Group of 4 cells
Sarcinae arrangement
Cubes of 8 cells
Strepto arrangement
chains of cells
Staphylo arrangement
Grape-like clusters of cells
Pink color after staining
Gram negative (G-)
Purple color after staining
Gram positive (G+)
A color dye used to visualize specific structures or cells on a sample (a smear) when viewing through a microscope is called:
Stain
A staining procedure that results in colorless (clear, unstained) bacteria against a dark stained background is called:
Negative (background) stain
The color- bearing ion in a stain is called:
Chromophore. If chromophore is negatively charged (anionic) it is repelled by bacteria.
This is generally used for negative staining which is known as:
Nigrosine
A thin film of material containing microorganisms spread over the surface of a clean microscope slide which is known as:
Smear
Using a flame; the heating of a smear on a slide briefly and gently. This procedure partially melts the cell walls of bacteria, causes cells to adhere (stick) to the slide so they wont wash off, kills the microorganisms and causes changes in the bacterial cells which causes them to stain better. This is called:
Heating-fixing
The chromophore is positively charged (cationic), it is attracted to and will only stain the slightly negatively charged bacteria. This is known as:
Basic stain
This is used when information about cell size, shape and arrangement are wanted. Methylene blue (basic stain) commonly used as simple stain.
- a single dye which is added to a smear
- A one-step staining procedure
- The use of a single stain to color a bacterial organism
This describes:
Simple stain
A stain that distinguishes bacteria based on their reactions to the staining procedure, this is due to a structural difference among different bacteria. This type of stain is called:
Differential stain
- Thick cell walls, many layers of peptidoglycan and teichoic acid
- No outer membrane (of lipids&proteins) external to the cell wall
- Retains the primary stain (crystal violet) and resists decolorization
- Sensitive to antibiotics, detergents, disinfectants, antiseptics and lysozyme
This all describes what?
Gram positive bacteria (G+)
An enzyme occurring naturally in human tears, mucus, saliva, capable of destroying the cell walls of certain bacteria (G+) and acting as a mild antiseptic. This is called:
Lysozyme
- Very thin cell walls of peptidoglycan (and no teichoic acid)
- An outer lipid protein membrane external to the cell wall
- The decolorizer, ethanol, removes the outer lipid protein membrae so the cell decolorizes
- Lose primary stain, crystal violet, and can be counterstained with safranin
- Appear pink
- More resistant to antibiotics, detergents, disinfectants, antiseptics, lysozyme
This all describes:
Gram negative bacteria
A substance added to a staining solution to make it stain more intensely; a fixative which forms an insoluble chemical complex with the crystal violet dye. This is called:
Mordant
What may go wrong with Gram variable cells?
- The smear can be too thick and all the cells may not decolorize
- Age, old cultures tend to be Gram variable. Cultures more than 24hrs old may contain non-viable cells that are beginning to decompose
- Exposing the smear on the slide to excessive heat when heat-fixing. This causes the cell walls to rupture and cells can decolorize.
- Overuse of the decolorizer
- underuse of the decolorizer
What is the primary stain?
Crystal violet
What is the counterstain?
Safranin
The ability of the bacterial cell to move by itself from place to place is known as:
Motility
Thin structures that are much smaller than the limit of resolution of the oil immersion lens. Complex structures composed of many different kinds of proteins. This is called:
Flagella
This type of media permits the isolation of specific groups of organisms from a mixed sample. Contains compounds that inhibit the growth of 1 group of organisms, while allowing the growth of another group of organisms to continue. This is known as:
Selective media
This allows for the recognition of specific types of bacteria growing in the culture This is known as:
Differential media
Microorganisms that grow and multiply in or on a culture medium. This is known as:
Culture
Many different microorganism growing together on a culture medium. Found in nature, especially on the body, soil, water and food. This is known as:
Mixed culture
Only that one specific species (1 type of microorganism) growing on the culture medium. Usual occurs under extreme environments. This is known as:
Pure culture
Why is it necessary to have a pure culture?
- The germ theory calls for a pure culture
- To identify unknown bacteria, need to have and maintain a pure culture
- need for identifying specific spoilage and pathogenic microorganisms
- Pasteur needed them to explain fermentation
- Needed to test for water quality and safety
- Needed to determine the quality and safety of food and milk
The microorganisms that are introduced to a sterile medium. This is called:
Inoculum
Methods used to obtain pure culture:
- streak plate method- physically spreading cells over the surface of solid media
- pour plate method
the degradation of tooth enamel and dentin in the formation of tooth decay. Occurs as a result of the production of lactic acid by bacteris in the presence of high levels of sucrose, considered bacterial infections & chronic disease, most widespread infection worldwide, microbes present in saliva & tooth plaque produce acid which can dissolve teeth, and acidogenic potential of microbes this is called:
Dental caries
The microorganism most frequently isolated from the surface of decayed teeth is called:
Streptococcus mutans
- Caries susceptibility test is a relatively simple test that has a high reliability
- Relies on the rapidity of microorganisms in the saliva to lower the pH in a medium that contains 2% dextrose (sugar)
- De calcification of enamel begins at pH 5.5 and progresses rapidly as the pH is lowered to 4.4 and less
- The demonstration of pH lowering becomes evidence of susceptibility to dental caries
What type of test is this describing?
Snyder test agar
If the results are green in a Snyder test agar, would it be positive or negative?
Negative
If the results are yellow from a Snyder test agar, would it be positive or negative?
Positive
A habitat supplying the factors necessary for the existence of an organism or species is called:
Ecological niche
What produces perspiration which contains nitrogenous wastes (urea, acid, ammonia) and nutrients (lactic acid)?
Sweat (sudoriferous) glands
What type of glands produce sebum?
Oil (sebaceous) glands
What is the normal pH of skin?
Between 4-6 pH
An oily substance composed of lipids and fatty acids is called:
Sebum
A tough, flexible, water proof protein found in skin cells of the epidermis and is a resistant barrier; and the low pH of the skin inhibits many microbes. This is known as:
Keratin
The ability of the established normal microbiota to prevent the overgrowth of harmful microorganisms. This is known as:
Microbial antagonism
Any non-living inanimate object that can carry and transmit bacteria and other microorganisms. This is only present on the skin for a few hours to a few days and is sensitive to antiseptics. This is called:
Fomite
What type of microorganisms does this describe?
- NOT permanent skin residents
- Vigorous hand washing can remove them all
- Easily removed from the skin and transmitted by fomites
Transient (Contaminant) microorganisms
Those organisms found in and on the human body. Which under normal conditions do not cause infection. Can only be removed by hand washing and are PERMANENT residents that are firmly entrenched in the skin. Mostly Gram +, less sensitive to antiseptics.
This describes:
Normal microbiota
The prevention of sepsis by preventing or inhibiting the growth of disease-causing microorganisms. Are chemical agents used on living tissues to destroy, inhibit, remove vegetative disease-causing microorganisms. This is called:
Antiseptics
Agents, such as heat or chemicals, that destroy, neutralize or inhibit the growth of disease-causing vegetative microorganisms on non-living objects and surfaces. This is called:
Disinfectants
Agents that physically remove microorganisms from a limited area of the skin, mostly a mechanical removal by soap and water, alcohol swab or other agent. This is defines:
Degermers
A visible mass of bacterial cells on the surface of solid media is called
Colony
- As bacteria grow and multiply on the surface of solid media they form colonies
- each colony consists of a mass of cells that arises from a single bacterial cell
- colonies produced by different bacterial species vary in their characteristics
- pure colony can be made by aseptically transferring a small inoculum to a fresh medium and using one of two common methods
These are facts for:
Facts that make the isolation of a pure culture possible
These characteristics describe what?
- The most important Staph
- normally found on the skin and nasal membranes
- causes: skin infections, throat infections, staphylococcal food poisoning and toxic shock
- causes these mixed infections: abscesses, boils, carbuncles, osteomyelitis and fatal septicemias.
Staphylococcus aureus
A localized collection of pus in anybody part that results from invasion of pyogenic bacterium, staphylococcus aureus. This is called:
Abscesses
Tender, dome- shaped, skin lesions; typically caused by an infection around a hair follicle with staphylococcus aureus this is called:
boils
A painful inflammation of the skin deeper tissues with the discharge of pus and dead tissue. This is called:
carbuncles
