The Microscope

Getting “Up Close and Personal” with the Cell

Getting “Up Close and Personal” with the Cell

History Review

Robert Hooke Anton van Leeuwenhoek Matthias Schleiden Theodor Schwann Rudolph Virchow

What does it mean? Micro- Scope-

Microscope Characteristics Magnification = making an image

appear larger than its actual size.

Resolution = how clear the image is.

Types of Microscopes

Compound Light Microscopes

Electron Microscopes Transmission electron microscope Scanning electron microscope

Scanning Tunneling Microscope

Compound Light Microscope Light passes

through one or more lenses.

Magnifies the image up to 2,000X

Is commonly used in classrooms.

Good to view shape of cells and movement (cells that are alive).

Parts of the Compound Light Microscope

Eyepiece = Magnifies the image 10X.

Low-power objective = magnifies the image another 4X.

High-power objective = further magnifies the image, from 10X to 40X.

Nosepiece = holds the objectives.

Parts of the Compound Light Microscope

Body tube = maintains distance between nosepiece and objectives.

Stage = holds the slide with specimen.

Coarse adjustment = moves the stage up and down to focus.

Fine adjustment = moves the stage slightly to focus image.

Parts of the Compound Light Microscope

Stage clips = hold the slide in place.

Light source = provides light for viewing the image.

Arm = supports the body tube.

Base = supports the microscope.

Diaphragm = controls the amount of light that passes through.

Electron Microscope

Two types: Transmission

Electrons Microscope (TEM)

Scanning Electron Microscope (SEM)

Can magnify an image up to 200,000X

Used to view small structures inside cells.

Can only view dead cells.

Transmission Electron Microscope (TEM)

Show details of cell’s interior.

Images usually black and white.

Computers may add color to the images.

Scanning Electron Microscope (SEM)

Shows 3-D images of cell’s surface.

Images are black and white.

Computers may add color to the images.

Scanning Tunneling Microscope

Used to view very small objects (even individual atoms).

Creates 3-D image of specimen’s surface.

Can be used to view living things.

Which picture belongs to which microscope (LM, SEM,

TEM)?

Microscope Interactive Website

http://www.wisc-online.com/objects/index_tj.asp?objid=BIO905

Integrating Math

If you are viewing a cell on a compound light microscope and the eyepiece has a magnification of 10x and you are using the 40x high power objective, what is the total magnification of the image?

(10x) X (40x) = 400x The cell is being magnified 400 times.

Review Microscope Handling Procedures

Review Questions

How does the light microscope differ from the electron microscope?

What kind of microscope is used in most classrooms?

Which microscope would you use if the object you were viewing was too thick to let light pass through it?

What advantage does the compound light microscope have over the electron microscope?