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MGY277 Exam Study Set
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MGY277 Exam Study Set ...
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MGY277 Exam Study SetJenner - Answer developed use of cowpox to vaccinate against smallpox
Semmelweis - Answer proposed hand washing: prevent spread of childbed fever in
maternity wards
Bassi - Answer -1st person to link microbe to disease
-found muscardine (fungal pathogen) that kill silk worms
Koch - Answer -founder of modern bacteriology
-discovered causes of anthrax, cholera, tuberculosis
-developed modern methods for working with microbes in lab
-postulates
Pasteur - Answer -disproved spontaneous generation: if sth is sterile it wont grow
microbes
-biggest contributor towards germ theory of disease
-developed techniques for vaccine production
Snow - Answer -one of the fathers of epidemiology
-mapped cases of cholera: contaminated water pumps
Lister - Answer -antiseptic surgery: instruments with carbolic acid (phenol)
-listerine named after him
refractive index - Answer measure of relative speed of light
bright field microscope - Answer -most common: cheap & simple
-ocular: 10X (at eyepiece)
-objective: 4X, 10X, 40X, 100X (for magnification)
-condenser: focuses light, DOES NOT magnify object
dark field microscope - Answer -directs light towards specimen at an angle, only light
scattered by specimen enters objective
-cells stand out bright against dark background
light microscope - Answer -magnify ~1000X
,-visible light spectrum (400~ 750 nm)
-cheap & simple
-easy to see shape, size, motility
electron microscope - Answer -magnify >100 000X
-fluorescent screen
-expensive & complicated
-must be in vacuum
-images black and white
-see more details: cell must be dead
scanning EM - Answer -3D: can see large specimens
-electrons scanned over surface
-for surface details
transmission EM - Answer -for fine detail of cell structure
-direct electrons that pass through or scatter
-dark areas = dense portions of specimen
-think sectioning: can see internal details, but can distort cells
gram-stain - Answer -inside of cell
-crystal violet stain (primary): cells are purple
-iodine (mordant): cells remain purple
-alcohol (decolorizer): gram+ = purple/ gram- = pink
-safranin (counterstain): gram+ = purple/ gram- = pink
differential staining - Answer distinguish different types of cell
e.g. gram, acid fast
simple staining - Answer -one dye
-increase contrast
immunofluorescence - Answer tag specific proteins fluorescently using antibody
-can detect specific organism
, -more expensive and complex than bright field
coccus - Answer -bacteria shape
-spherical
rod/ bacillus - Answer -bacteria shape
-cylindrical
streptococcus - Answer -groupings of bacteria
-long chains
-divide in same plane
sarcina - Answer -groupings of bacteria
-cubical packets
staphylococcus - Answer -groupings of bacteria
-grapelike clusters
-divides in different planes
porin proteins - Answer open channels for gram (-) outer membrane
peptidoglycan - Answer -one subunit = 1 NAM, 1 NAG, tetrapetide
-wall peptides end with 2 D-alanines (have L-AA in proteins)
-transpeptidation: side chain of AA in one subunit linked to C-term of another (after a
D-Ala is removed)
LPS - Answer -only in outer surface of gram (-)
-O antigen, score polysaccharide, lipid A
-change O antigen the most (what bacteriophages bind): low conservation
-lipid A & PG: high conservation
viruses - Answer -obligate intracellular parasites
-not alive outside cell
-basically gene info (DNA or RNA) in protective coat
-challenging to study: cannot be grown in pure culture; require live cells and electron
microscope
-= nucleic acid + protein coat (capsid)
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