Tools of Biologists

Types of Microscopes

Optical Microscope - One Lens only

Compound Microscope - 2 lens and has limited resolution

Dissecting Microscope

  • Objects appear normal

  • very low power

  • kinda crappy

Electron Microscope

  • very fancy and expensive

  • on a VERY fine scale

  • specimen must be thinly sliced

  • no living samples!!

  • 500,000x

  • scanning and transmission scope

  • only in black and white

Microscopy - The use of or investigation using a microscope


Microscope Units

  • micrometer (micron) = 1/1000 of a millimeter

Compound Microscope

  • specimen must be thin enough for light to pass through

  • magnification determined by ocular lens x objective lens = magnification

  • more magnification mean more light

  • object appear upside down and backward

  • never use coarse and high power knob together

  • always start with the lowest magnification and work our way up

Mounts

  • wet mount = don’t touch specimen with water dropper. any water bubble, just tap the slide.

  • wet mount stain = adding stain or colored dye to increase details of a specimen

Microscope Study Methods

Fixing - cutting specimens and soaking in fixative

embedding - submerge specimens in liquid wax

sectioning - using a machine called a micro tone and making extra thin slices

centrifugation - when substances are separated by density

micro dissection - a teeny tiny version of a dissection that include tiny tools to!!

spectrophotometry - measuring an amount of light

chromatography - method of separating chemicals

Formulas

Field of View

  • Is represented as “i” on the triangle

  • when under low power, use a millimeter rules and measure diameter against the slide

  • then you can convert to micrometers (move decimal 3 to the right or multiply by 1000)

  • when the magnification increase, the FOV decrease

  • how to find FOV

    • low power magnification dived by the high power field of view

    • WHICH IS THE SAME AS high power FOV divided by low power

Finding Object Size on Microscope

  • Represented as ‘a’ on the triangle

  • estimate! (decide the diameter of FOV by the number of object that can fit across it)

Total Magnification

  • Is represented as “m” on the triangle

  • Multiply the actual size and image size

  • HOWEVER, you can also just multiply the ocular lenses together

    • example; 10x(4x)40x = 1600x (total mag)