ImportanceImportance

One of the most widely used tools in One of the most widely used tools in Biology Biology

Produces enlarged images of objectsProduces enlarged images of objects Microscope animation    

Microscopy Terms Microscopy Terms

MagnificationMagnification – the increase in an – the increase in an object’s apparent size   object’s apparent size  

ResolutionResolution – the power of a – the power of a microscope to clearly show detailmicroscope to clearly show detail ClarityClarity Focus Focus

TYPES OF MICROSCOPESTYPES OF MICROSCOPES

Compound Light Microscope  Compound Light Microscope   Electron Microscopes  Electron Microscopes  

Compound Light Microscope  Compound Light Microscope   Thin sliced and sometimes stained specimen is Thin sliced and sometimes stained specimen is

mounted on a slide to be viewed mounted on a slide to be viewed Uses a light source (a light bulb or mirror)Uses a light source (a light bulb or mirror) Light passes through the specimen and through the Light passes through the specimen and through the

objective lens objective lens total magnification= power of magnification of total magnification= power of magnification of

objective lens x the power of magnification of the objective lens x the power of magnification of the ocular lens ocular lens Ex. 40 X 10 = 400X total magnificationEx. 40 X 10 = 400X total magnification

Limitations of Compound Limitations of Compound Light MicroscopesLight Microscopes

The Resolution decreases as The Resolution decreases as Magnification increases Magnification increases

Electron Microscopes   Electron Microscopes   Able to view extremely small objects   Able to view extremely small objects     Uses a Beam of Electrons, rather than Uses a Beam of Electrons, rather than

light to produce an enlarged image   light to produce an enlarged image   Electron microscopes are more powerful Electron microscopes are more powerful

than LM's   than LM's   There are several types of electron There are several types of electron

microscopes microscopes

Transmission Electron Microscope Transmission Electron Microscope   

(TEM)(TEM) Can magnify objects up to 200,000 X  Can magnify objects up to 200,000 X  Projects image onto a screen or Projects image onto a screen or

photographic plate   photographic plate   Greatly magnifies internal details of a Greatly magnifies internal details of a

specimen specimen Cannot be used to view living specimensCannot be used to view living specimens    

(TEM)(TEM)

Scanning Electron Microscope Scanning Electron Microscope (SEM)(SEM)

Produces a 3-D image   Produces a 3-D image   Produce magnified image of Produce magnified image of surfacesurface details details Can magnify up to 100,000 times Can magnify up to 100,000 times   Can not be used to view living specimens  Can not be used to view living specimens     A beam of electrons is passed over the A beam of electrons is passed over the

surfacesurface of a metal coating of a metal coating Showered electrons are projected onto a Showered electrons are projected onto a

fluorescent screen or photographic plate  fluorescent screen or photographic plate  

(SEM)(SEM)