Microscopy

-Solid specimens

-Thin slices called sectioning, coverslip placed on top

Uses: hair, pollen, muscle tissue, plant tissue, muscle tissue

-Wet specimens

-suspended in water or immersion oil, cover slip placed at an angle

Uses: Aquatic samples and other living organisms

-Soft specimens

-Wet mount squashed between slide and coverslip

Uses: Root cells to look at cell division

-Body fluid specimens

-The edge of slide used to smear sample, create thin even coating

Uses: Blood smears to view erythrocytes

Samples sometimes need to be stained, as cytosol and other cell structures may be transparent or difficult to distinguish.

-Sample is first air-dried

-Then heated by passing it through Bunsen burner flame

-This allows sample to be fixed to the slide and take up stain.

Stains cell walls purple, used in gram staining

Stains the nuclei in animal cells to give contrast

Negative stain that is not taken up by the cell but provides a contrast between the cell and the background

1mm to 1μm= x1000 (vice versa)

1μm to 1nm= x1000 (vice versa)

Used to measure the size of the object when viewed under a microscope

-A disc placed in the eyepiece with 100 divisions

-Calibrated to the stage micrometer at each magnification

* 1 graticule division= no. of micrometers / no. of graticule division

* Graticule divisions x Magnification factor= measurement (μm)

is how many times bigger the image of the specimen observed is in compared to the actual size of the specimen

eyepiece lens magnification x objective lens magnification = total magnification

The ability to distinguish between two separate points.

The minimum distance that allows two objects to be viewed as separate.

Wavelength of light