Week 2: Microscopy Flashcards
what are the three principles of microscopy?
magnification
resolution
contrast
what magnification should be used to focus my sample first? then what?
10X, then move to higher magnification
what height should i start at with the 10X lens?
maximum height, then move the stage down until it comes into focus
100X always uses…
oil
oil is always used with…
100X
what magnification should i use on a unstained human red blood cell?
10X
what contrast should i use on an unstained human red blood cell?
BF
what resolution should i use on a unstained human red blood cell?
air
what magnification should i use on a capsule stained bacteria cell?
100X
what contrast should i use on a capsule stained bacteria cell?
DF
what resolution should i use on a capsule stained bacteria cell?
oil
what magnification should i use for eukaryotic cells?
40X
what magnification should i use for bacterial cells?
100X
when to use bright field?
live, no stain
when to use dark field?
capsule
when to use phase contrast?
unstained/colorless cells because staining provides a contrast
what resolution with 100X?
oil
what resolution with 10X?
air
what resolution with 40X?
air
when should i avoid bright field?
when viewing unstained wet mounts
how do organisms appear in dark field?
bright and glowing against a dark background
what magnification can and can’t we use with dark field?
CAN: 10X and 40X
CAN’T: 100X
what is the best contrast setting for unstained live organisms?
phase contrast
phase contrast is the best setting for…
unstained live organisms
match phase ring to objective: PH1
10X
match phase ring to objective: PH2
r40X
match phase ring to objective: PH3
100X
match objective to phase ring: 100X
PH3
match objective to phase ring: 40X
PH2
match objective to phase ring: 10X
PH1
what contrast to use for 100X?
BF/phase contrast for 100X, not DF
how to use oil immersion lens?
- 100X needs oil
- focus sample in 40X
- go back to 10X and put oil onto the slide.
- move 100X into place
