Study Guide Lecture 1 Part 2 Flashcards
Is a microscopic organism that is too small to be seen with the naked eye
Microbes
Refers to a set of practices and procedures used to prevent contamination by unwanted microorganisms in medical, laboratory, and other settings.
Prevent contamination of sterile surfaces
Aseptic technique
Hand hygiene
Sterilization of equipment
Use of PPE
Disinfecting surfaces
Minimizing exposures
Aseptic techniques
A ______ is a substance used to set or stabilize stains of dyes; in this case, grams iodine acts like a trapping agent that complexes with the crystal violet, making the crystal violet iodine complex clump and stay contained in thick layers of peptidoglycan in the cell walls.
Mordant
Combines positive staining with negative staining
Basic dye stains the cell
Acidic dye stains the background
The ______ appears as a halo around a colored cell
Capsule
The major component of bacterial cell walls is called _______; it is only found in bacteria.
Peptidoglycan
Typically Form the bulky mass of extra cellular matrix
Proteoglycans
Gram negative cell walls are structurally more complex, containing a thin layer peptidoglycan and an outer membrane containing
Lipopolysaccharide
Functions as an endotoxin in infections involving gram negative bacteria, contributing to symptoms such as fever, hemorrhaging, and septic shock.
Lipopolysaccharide
States that diseases may result from microbial infection
Germ theory of disease
Occurs when when a wave bounces off of a material.
A red piece of cloth may reflect red light to our eyes while absorbing other colors of light.
Reflection
Occurs when a material captures the energy of a light wave.
In the case of glow and the dark plastics, the energy from light absorbed and then later re-emitted as another form of phosphorescence.
Absorbance
Occurs when light waves change direction as they enter a new medium
Refraction
Is defined as the ability of a lens to enlarge the image of an object when compared to a real one
Magnification
Magnification of 10X means that the image appears _____ the size of the object as viewed with the naked eye
10 times larger
Is the ability to tell that two separate points or objects are separate
Poor _____ results in a fuzzy image
Resolution
Resolution is affected by
Wave length
Numerical aperture
The _____ of a lens indicates how much it can magnify a specimen
Power
Bacteria require greater _____ than eukaryotic cells
Magnification
Is the visible difference between a specimen and its background
Contrast
Most cells are transparent, resulting in low _____ when viewed on a light background
Contrast
Staining cells increases ______, increasing visibility
Contrast
Placing _____ between the lens and specimen reduces refraction
More light is captured by objective lens
Results in greater resolution at higher magnification
Immersion oil
Immersions oil lenses (usually 100x) are specially designed to be used with immersion oil. Do not use immersion oil with
40 x objective
Adheres the specimen to the slide
Kills the cells
Coagulates cytoplasm proteins, which can increase visibility when stained
Common fixatives : heat and chemicals
Fixation
If a sample is to be stained a ____ must be made
Smear
A ____ is composed of all the microbes that live in and on a host
Estimated ranges 1:1 to 10:1
Microbiome
Colonize the host long term
Do not cause disease under normal conditions
May cause opportunistic disease
Normal microbiota
Colonize the host for a short period of time
May be present for days, weeks, or months
Transient microbiota
This pump uses ATP as energy to move three Na+ ions out and two K+ in
Sodium potassium pump
More microbes are established during and immediately after birth
Vaginal birth
Cesarean birth
Lactobacillius and bacteriodes
Staphylococcus epidermis
Antibiotic use is associated with
Yeast infections
Vaginitis
Thrush
C. Difficile colitis
Is a disease caused by a eukaryotic parasite transmitted to humans by mosquitoes
Malaria
Is a common fungal infection of the skin
Ringworm
Causes thrush and vaginitis
Candida albicans
A dimorphic fungus, causes subcutaneous mycoses also know as
Rose gardener disease
Algae May cause disease in humans due to harmful algal blooms
Red tide
Is an effective method to distinguish between bacteria with different types of cell walls, and is the most frequently used staining techniques
Gram staining
Steps to gram staining
- First crystal violet, primary stain is applied to heat fixed smear
- Next gram mordant is added
- Next a decolorizing agent is added usually an ethanol or an acetone
- Finally a counterstain usually Safranin
Gram stain process step 1
Crystal violet
Primary stain is added to specimen smear
Stains cells purple or blue
Gram stain step 2
Iodine
Mordant makes dye less soluble so it adheres to cell walls
Cells remain purple or blue
Gram staining step 3
Alcohol
Decolorizer washes away stain from gram negative cells
Gram positive cells remain purple or blue
Gram negative cells remain colorless
Gram staining step 4
Safranin
Counterstain allows dye adherence to gram negative cells
Gram positive cells remain purple or blue
Gram negative cells appear pink or red
An ______ is able to differentiate two types of gram positive cells: those that have waxy mycolic acids in their cell walls, and those that do not.
Acid fast stain
Do not absorb basic dyes; therefore, a negative staining technique (staining around the cells) is typically used for _______.
The dye stains the background but does not penetrate the capsules, which appear like halos around the borders of the cell.
Capsule staining
Uses two stains to differentiate endospores from the rest of the cell. The schaffer Fulton method uses heat to push the primary stain _________ into the endospore. Washing with water decolorizes the cell but the endospore retains the green stain.
Counter stain for endospore staining ?
Endospore staining
Malachite green
Safranin pink
Endospore staining techniques are important for identifying ____________ and _________, the two genera of endospore producing bacteria that contain clinically significant species.
Bacillus and clostridium
Anthrax and c. Diff
The waxy acid fast cells retain the carbolfuchsin even after a Decolorizering is applied, a secondary counter stain methylene blue, is then applied, which renders non acid fast cells blue.
Acid fast staining
When light passes from one medium to another, the light ray bends
Refraction of light
Are tail like cellular structures used for locomotion by some bacteria, archea, and eukaryotes
Flagella
