lab 1ab microscopy and cells

Ocular lens (eyepieces)

the lens you look through, magnification etched on the side (10x)

Turret (revolving nosepiece)

holds the objective lens

Objective lens

4x scanning (low power) lens, 10x medium power, 40x high power, 100x oil immersion; magnification on the lens

Stage

the flat part where you place the slide

Condenser lens

focuses light through the stage and onto the specimen

Iris diaphragm

controls the amount of light that reaches the slide; diaphragm lever is on the condenser lens

Coarse and fine focus knobs

allows you to bring your specimen into focus; always start with the coarse focus and the 4x, then only use the fine focus for all other higher power objective lens

Lamp and rheostat

rheostat controls the intensity of the lamp; rheostat found on base of microscope

Magnification

the factor by which an image appears larger than the actual object

Total magnification

• Power of objective lens, magnifies everything by label

• Multiply power of objective lens (10x) by power of ocular lens

• 4x objective lens, 10x ocular lens, total magnification is 40x

Resolution light

wavelength of light that determines level of detail

Microscope

by using light or electrons passing through specimen and then the glass lens, the image is magnified

Depth of field

how deep into a specimen you can see at a particular magnification

Field of view

how much of your specimen you can see with the lens

Cocci

spherical

Bacillus

rod-shaped

Spirillum

spiral-shaped

Gram stain

allows us to differentiate bacteria based on cell wall structure

Gram-negative

thin layer of peptidoglycan and thin lipid outer plasma membrane, looks red

Gram-positive

thick layer of peptidoglycan that holds crystal violet, looks purple