Ch 4 Flashcards
Microorganism
Organisms that are too small to be seen with the naked eye we use microscope to see microorganisms, and other microbes, micro organisms include bacteria, archaea, fungi, protozoa, microscopic, algae
Sizes from big to small
KM big—-M—— CM—— MM—— UM—-NM very small
Bacteria is measured in
Micrometers
Viruses are measured in
nanometers
Light microscope
Light microscope uses visible light to observe specimens light microscope can magnify up to 1000 X
Most common is the brightfield compound light microscope
Ocular lens is 10 X and includes 4 10 40 100 oil immersion only
Refractive index
Measure of the bending of a light ray, when will it from one medium to another, adding oil to the side, helps the light to stay and focus on the slide because it prevents and reduces refraction
Light, microscope, and contrast
Because many micro organisms are transparent there’s a need for microscope contrast or stain in order to see these microorganism
However, straining is not always desirable because I could kill or damage cells some cells can’t be stained
Dark field microscope’s
are use the dark background to examine live cells. No alteration of the cells can be used to see the bacteria that causes syphilis.treponema palidium
Fluorescent microscope
Cells or materials, either naturally fluorescent or tag with fluorescent dyes
Molecules absorb light at one wave length usually an ultraviolet light, and I meant like at the longer length wave
Most today our epic fluorescent UV projected onto Not through specimen
Electron microscope’s
Uses wave length of electrons which give greater resolutions instead of light
Used for images, too small to be seen by light microscope, such as viruses
Total magnification from from 100,000 to 1,000,000 times
3-D images
Transmission electron microscope’s TEM
Beam of electrons pass through a dense slice of the specimen, used to see the inside of a cell to see a 2-D image
Staining: preparing specimens for microscope
Number one smear: a thin film of a material containing microorganism spread over a slide
Number two air dry
Number three heat fixing attaching microbes to the slide the skills of microbes . You do the step by sliding through the flame 2 to 3 times to heat, fix a specimen
Number four stain the slide
Number five exam in the microscope 
Differential staining
Gram staining most common for bacteria
Acid-fast staining used for mycobacteria tuberculosis
Prokaryotic cells
Cell envelope includes capsule cell wall cytoplasmic membrane
Gram-positive cell wall versus gram-negative cell wall
Gram-positive has that teichoic acid and lipoteichoic acid? And has a thicker peptidoglycan layer
Gram-negative is closer to the outer membrane and has a thinner peptidoglycan cell wall 
Two common bacteria, cell shape types
Coccus round
Bacillus rod shaped 
Colors in gram staining
Gram-positive stands,, purple,
Graham negative red and pink
gram staining in healthcare
We use gram staining and healthcare to see if bacteria is present, and it narrowed down the possible bacteria type
Gram staining steps
One crystal violet stain, inside of all cells, purple
Two iodine is added, and forms of crystal violet iodine complex. That the cell wall prevents from being washed out, so the cell remains purple.
Three decolonizing agent, for the alcohol is added, and this remove the dye iodine complex from the gram-negative bacteria, but not from the gram-positive bacteria
Four a secondary stain or counterstain red dye saffron is added to give a different color to the now colorless, gram-negative, bacteria cells
Five. End result, gram-positive, bacteria, stain, purple, gram-negative, bacteria, stain, pink, or red.
Limitations to gram staining
Not all bacteria can be tested using gram staining
Some bacteria are Graham variable
Sam do not have a cell wall mycoplasma so Gram stain does not work
Gram stain’s alone John provide a diagnosis but it can help to narrow down the potential bacteria causing the infection to help lab. Focus on additional testing needed.
Can we use gram staining on archaea eukaryotes
Archaea do not have peptidoglycan in their cell walls and they have pseudo peptidoglycan and some pieces do not have any. They are very diverse and we don’t. We don’t use gram staining for archaea
Acid fast staining
Used to detect mycobacterium
Cell wall contains high concentration of mycolic acid
Waxi fatty acid that prevents uptake of dye
Harsher methods needed
Myco bacterium tuberculosis
Affects the lungs
weakness weight loss, chills, fever, night sweats 6 to 12 months treatment with antibiotics
Mycobacterium leprae
Affects the nerves, skin eyes and nasal mucosa
Can lead to nerve damage crippling of hands/feet paralysis, and blindness is left on treated
Endospore stain
Members of genera include bacillus clostridium
Form resistant, dormant endosperm
Appear as clear objects when put against Gram stain
Endo sporran staying uses heat to facilitate uptake of the primary dye malachite green
Counterstain usually saffron, used to visualize other cells
Endospore stain
Members of genera including bacillus and clostridium form resistant dormant often appear as clear objects when Gram stain endospore stain uses heat to facilitate uptake of the primary dye malachite green by endospore counterstain used to visualize other cells
Flagella stain
Flagella stain is used commonly for prokaryotic motility, and is too thin to be seen with light microscope. The flagella stain coats the flagella to thicken and make visible presents and distribution can help and identification.
