Microscopy

Microscope DEFINE: instrument that produces enlarged image of object Used to study organisms, cells, and cell parts Increase image of object and Show object’s details MAGNIFICATION: increase of object’s apparent size RESOLUTION: power to show object’s details clearly

Light Microscopes COMPOUND LIGHT MICROSCOPE (LM) To see small organisms and cells Specimen must be cut thin enough so light can pass through and mounted onto glass slide Different set magnifications

Light Microscope

Parts of LM STAGE: supports specimen LIGHT SOURCE: mirror, light bulb; directs light upwards, through specimen OBJECTIVE LENS: enlarges image of object NOSEPIECE: holds objective lens of different magnifications OCULAR LENS: near eyepiece; magnifies image further CONDENSER/ DIAPHRAGM: controls the amount of light projected to specimen COARSE FOCUS: focuses object into view FINE FOCUS: focuses fine details of object into view

Electron Microscope At about 2000x magnification images become blurry Uses beam of electrons instead of light to enlarge image of specimen Types: Transmission Electron Microscope (TEM) Scanning Electron Microscope (SEM) Black Walnut Tree Leaf

Transmission Electron Microscope Transmits beam of electron through very thin slice of specimen Magnetic lenses enlarge image and project it in screen or photographic plate PRO: 200,000x magnification CON: Can NOT view living things

Scanning Electron Microscope Provides 3-D images Specimen not sliced but coated with a fine metal spray Electrons bounce off metal coating and projected onto fluorescent screen of photographic plate PRO: 100,000x magnification; 3-D image CON: Can NOT be live specimens

LM vs TEM vs SEM Diatom, 1000x Mitochondria, mammalian lung Fly Head

USING THE COMPOUND LIGHT MICROSCOPE WET MOUNT REVIEW MOVING THE SLIDE LETTER INVERSION DEPTH OF FIELD MAGNIFICATION EYEPIECE (10x) x LENS (10X LOW OR 40X HIGH)=100X, 400X

USING THE COMPOUND LIGHT MICROSCOPE MEASUREMENT IN MICROMETERS ( µ ) 1mm = 1000 µm and .001mm = 1 µm DIAMETER OF FIELD EXAMPLE UNDER HIGH POWER DIAMETER (LOW POWER)= 4 mm DIAMETER (HIGH POWER) 40/10 = 4 4000/4 = 1000 µm PROPER CARE AND USAGE

MICROSCOPE LAB DIRECTIONS SUMMARY TEXTBOOK PAGES 691-694 NOTES: SEE MATERIAL LIST ON P.691 SKIP STEP #’S 19-24 REVIEW MICROSCOPE DIAGRAM ON THE TOP LEFT OF P.692 FOR PARTS A AND B YOU DO NOT HAVE TO DO TABLE PC.1 FOR PART C, MAKE WET MOUNT SLIDES OF THE LETTERS O, C, AND E AND DRAW WHAT YOU OBSERVE UNDER LOW OR HIGH POWER (10X OR 40X). KEEP YOUR WET MOUNT OF THE LETTER “E” FOR #33. NOTICE WHAT HAPPENS TO YOUR SPECIMEN WHEN YOU MOVE THE SLIDE ONE WAY OR THE OTHER. PAY ATTENTION TO WHAT HAPPENS TO YOUR FIELD OF VIEW WHEN YOU INCREASE MAGNIFICATION (AS WELL AS IF YOU HAVE TO ADJUST YOUR LIGHT DIAPHRAGM). FOR PART D, USE THE COLORED THREADS SLIDE IN THE BACK OF THE ROOM FOR #25-30. FOR PART E, USE THE TRANSPARENT RULER IN THE BACK OF THE ROOM TO MEASURE YOUR FIELD OF VIEW USING THE 4X OBJECTIVE LENS (USE mm MARKINGS AND PLACE THE RULER ON THE FAR LEFT OF YOUR FIELD OF VIEW, MAKE YOUR MEASUREMENT AND THEN CONVERT IT TO MICROMETERS). FINISH THE LAB BY DOING ANALYSIS QUESTIONS #1-6 ON P.694.

How to Use the Microscope

MICROSCOPE QUIZ FORMAT 21 M.C. QUESTIONS 3 M.C. BONUS QUESTIONS (1 PT. EACH) REVIEW: OUTLINE SHEET, LAB ANALYSIS QUESTIONS, STUDY GUIDE QUESTIONS, MICROSCOPE DIAGRAM p.692