Bright Field Microscope-produces a dark image against a brighter background,
-Most common
-Must fix cells
-Color of stain=bacteria color
-100x requires oil
-Light is bet through objective
-Basic dyes binf to neg
-Acidic dyes bind to pos
Dark Field Microscope-Background is dark, organism is ...
MIP 300
Questions and Answers
Bright Field Microscope✅✅-produces a dark image against a brighter background,
-Most common
-Must fix cells
-Color of stain=bacteria color
-100x requires oil
-Light is bet through objective
-Basic dyes binf to neg
-Acidic dyes bind to pos
Dark Field Microscope✅✅-Background is dark, organism is light
-Light is refracted by organism
-in the field, dont have to heat fix or stain
ex.Syphilis
phase contrast microscope✅✅-Shades of grey to show contrast in cell components
-slight differences in refractive indexes into light intensity
-Motility because no fixing or staining
fluorescence microscopy✅✅-Uses UV light to excite fluorescent molecules
-Some cells take up the dye
-Common in studying viruses
Magnification✅✅Objective X eyepiece
Resolution✅✅the ability of the lenses to distinguish between objects that are close together
Best resolution is .2um
human cells✅✅10-100 micrometers
Bacteria✅✅1 micrometer
Viruses✅✅.01-.1 micrometer
electron microscope✅✅-Resolution 1000x better than light
-Start to see viruses
Simple stain✅✅1 stain is used to increase microbes visibility
,Differential stain✅✅Divides microbes into different categories depending on structural
differences
Gram stain✅✅-Separates bacteria by the type of cell wall they have
-most common stain
Pos=purple neg=pink
acid fast stain✅✅Identifies bacteria that are neither gram + or -
that hav a thick waxy layer(mycolic acid) around them
Pos=hot pink Neg=blue
endospore stain✅✅Identifies spore-producing bacteria
Green spores pink vegetative cells
sporangium✅✅spore capsule in which haploid spores are produced by meiosis
flagella stain✅✅identifies bacteria that possess flagella used for motility
Coccus✅✅A spherical bacterium.
Diplococci✅✅cocci growing in pairs
Streptococci✅✅bacteria that form a chain
Staphylococci✅✅in random planes grape like clusters
Tetrads✅✅in 2 planes 4 cell groups
sarcina✅✅in three planes cube of 8 cell groups
Bacillus✅✅Rod shaped bacteria
coccobacillus✅✅short round rod, resemble cocci
diplobacillus✅✅bacillus growing in pairs
streptobacillus✅✅chain of rods
Vibrios✅✅comma shaped rods
Spirals✅✅long rods twisted into corkscrews
Spirilla✅✅spiral shaped bacteria with flagella
, Spirochetes✅✅corkscrew-shaped w/o flagella
Axiofillament✅✅Protein that wraps around and twitches it to move
Phospholipid bilayer components✅✅-phosphotidylethanolamine
-Hopanoids
-Proteins and glyco proteins
-Peripheral and integral proteins
hopanoids✅✅-Structurally similar to sterols
-stabilize membrane
Proteins✅✅-Nutrients and waste transport
-secreted protein transport
-Carry out metabolic processes
-Interaction with environment
-Flagellar motors
cell envelope✅✅All structures outside the Plasma membrane
-Peptidoglycan
Cell wall✅✅-Gives shape cell
-protection from osmotic pressure
-Protection from toxic substances
Gram neg cell wall✅✅-Large periplasmic space
-Periplasmic enzymes
This peptidoglycan layer
-Outer membrane
periplasmic space✅✅The space between the inner and outer cell membranes in Gram-negative
bactera. The peptidoglycan cell wall is found in the periplasmic space, and this space sometimes
contains enzymes to degrade antibiotics.
outer mebrane✅✅-Porin proteins allow for molecules to pass
-Larger molecules transported by permeases
-holds in periplasmic enzymes
-Avoid immune difenses
-Barrier to toxins
-contain endotoxin(LPS)
permeases✅✅substrate-specific carrier proteins
Endotoxins✅✅released only when bacteria die and their cell walls break down
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