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Bio 196 L > Light Microscopy > Flashcards

Light Microscopy Flashcards

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Biology 101 flashcards
1
Q

Proper care and handling of the microscope

A
  1. Always carry the microscope in front of you with one hand under the base and the other on the grasping hand
  2. Do not remove parts of the microscope
  3. Report any malfunctioning microscope to your instructor. You will not be penalized. Also report any broken slides and slides in which you can’t find a specimen.
  4. Do not tilt the microscope. Keep it flat on the bench top
  5. Keep the stage clean and dry to prevent rust.
  6. DO NOT USE THE OIL IMMERSION OBJECTIVE WITHOUT OIL. IT WON’T WORK PROPERLY. IF YOU USE OIL, BE SURE TO CLEAN THE SLIDE AND THE OBJECTIVE LENS AFTER USE.
  7. The ocular lenses, objective lenses, and the microscope stage can be cleaned using Kimwipes with glass cleaned on the paper. Do NOT spray cleaner onto the scope directly. Slides are also cleaned this way. Paper towels can scratch glass.
  8. THE SCANNING OBJECTIVE (SHORTEST, 4X) SHOULD BE IN POSITION AT THE BEGINNING AND THE END OF USE.
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2
Q

Eyepiece

A

Contains the ocular lenses. This is the part you look into.

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3
Q

Ocular lenses

A

Our microscopes have 10x or 15x

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4
Q

binocular

A

Equipped with two ocular lenses

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5
Q

Diopter ring

A

Allows for the possible inconsistencies of our eyesight. If your microscope has this, you may twist the ocular lens on the right to focus it separately.

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6
Q

Head

A

Upper part containing the oculars and rotating nose piece

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7
Q

Arm

A

Narrow, vertical part connecting the head and the base. Provides a carrying handle.

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8
Q

Nosepiece

A

Revolving device that holds objective lenses. The viewer can rotate the nose piece to change objective lenses.

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9
Q

Mechanical stage

A

Flat, movable area that holds and supports microscope slides.

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10
Q

Stage clips

A

Keeps the slide in place on the stage. The clips are spring loaded.

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11
Q

Stage control

A

Knob that allows the mechanical stage to move up/down and left/right

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12
Q

Iris diaphragm lever

A

Found just beneath the opening in the stage. Controls the amount of light used to illuminate the object. It can change the angle of the light rays creating contrast, making transparent items more visible.

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13
Q

Condenser

A

Below the stage. It features B for brightfield, D for darkfield and various other settings that bend or dim the light.

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14
Q

Condenser adjustment knob

A

Allows the viewer to position the condenser. Start with it closest to the stage

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15
Q

Coarse adjustment knob

A

At the base of the arm. Will raise and lower the stage, changing its distance from the lens. Used to bring object into initial focus; used only with the scanning (4X) lens

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16
Q

Fine adjustment knob

A

Raises and lowers the stage in smaller increments, used to bring object into final adjustment once the initial focus has been made. Used with any lens

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17
Q

Lamp

A

Light source for illumination of the specimen

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18
Q

Rheostat

A

Dial that adjusts the light intensity

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19
Q

Base

A

Supportive, flat surface of the microscope that rests on the table.

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20
Q

Scanning objective

A
  1. 4X magnification. ALWAYS used for the initial focusing of the slide. Should be in place before the slide is inserted and again before it is removed. Used to view a large portion of the slide (large field of view, low magnification)
  2. 40 total magnification
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21
Q

Low power objective

A
  1. 10X magnification. Longer than and used after the scanning power objective
  2. 100 total magnification
22
Q

High dry power

A
  1. 40X magnification. Used to view an object in even greater detail.
  2. 400 total magnification
23
Q

Oil immersion objective

A
  1. 100X magnification. Designed to be used only in conjunction with oil immersion to view specimens with the greatest magnification
  2. 1000 total magnification
24
Q

You need more light when you

A

Increase the objective

25
Q

Refraction

A

bending of light

26
Q

Focusing the magnification

A
  1. Keep both eyes open when looking through the eyepiece. Closing one eye can result in the eyestrain and headaches. Remember to adjust the distance between the oculars if you do not see light through both eyes when looking through the oculars.
  2. With the coarse adjustment knob, drop the stage to its lowest point.
  3. Make sure the 4X objective is in place; rotate the nosepiece until the scanning power objective is in place over the stage and you hear it click into position.
  4. Place the slide into the microscope specimen side up. Use the stage clips to secure it.
  5. Use stage control knobs to move the slide until the specimen is centered over the light.
  6. Raise the stage with the course adjustment knob until the slide and objective lens are at their closest point. While doing this, watch from the side, NOT by looking into the eyepiece.
  7. Looking into the eyepiece, adjust the light intensity using the rheostat dial (~5-7). Overly bright light may hide the object and cause eyestrain.
  8. While looking through the oculars, slowly turn the coarse adjustment knob (moving the stage downward) until the specimen is in focus.
  9. Slowly turn the fine focus adjustment knob to sharpen the image.
  10. Holding the rotating nose piece (not the lens), rotate the nose piece to the next lens (10X) until it clicks in place.
  11. Slowly turn the fine focus knob ONLY to focus the specimen at this higher magnification. Compound light microscopes are parfocal. Once the initial focusing is completed at scanning power, the course adjusment knob is not used again.
  12. The light intensity may need to be increased as the magnification is increased.
  13. If the specimen is no longer visible at 10X or 40X, you will need to refocus the specimen starting with the scanning (4X) lens. Do not yet attempt to use the 100X oil immersion lens.
  14. Notice the change in the working distance (the distance from the slide to the objective lens) as you change from one objective lens to another.
27
Q

How is the image of the letter “e” affected by magnification and movement of the slide?

A

The letter is is upside down and speckled

28
Q

Parfocal

A

Once the object is in focus with the scanning objective (4X), it should also be in reasonable focus at medium and high powers.

29
Q

Total magnification

A
  1. The magnification of the specimen when viewed through the microscope compared to the unaided eye.
  2. Calculated by multiplying the magnification of the ocular lens by the magnification of the objective lens.
30
Q

Resolution

A
  1. The shortest distance between two points on a specimen that can still be distinguished be the observer or microscope as separate points.
  2. As magnification goes up, THIS also goes up.
31
Q

Field of view

A
  1. The area of the slide that can be viewed when peering through the oculars.
  2. As magnification goes up, THIS goes down.
32
Q

When using the high dry power objective lens is the field of view larger or smaller than the low power objective lenses?

A

Smaller

33
Q

When using the high dry power objective lens is the working distance greater or lesser than the low power objective lens?

A

Lesser

34
Q

Working distance

A
  1. The distance from the slide to the objective lens.

2. When total magnification is higher, THIS is lesser.

35
Q

Depth of field

A

The vertical distance the remains in focus at one time.

36
Q

Procedure for making wet mounts

A
  1. Obtain a clean slide. Add a drop of specimen, if it is in solution. If the specimen is dry, first add the specimen, then add 1-2 drops of water.
  2. Take a clean coverslip and contact the edge of it to the edge of the water drop. Slowly lower the coverslip at an angle down over the specimen.
  3. Wick the excess fluid if necessary by placing a folded kimwipe at the edges of the coverslip. Do not press on the coverslip.
  4. When finished viewing under the microscope, make sure you dispose of the slide in either the glass disposal bin, or the biohazard glass disposal if so directly by your instructor.
37
Q

Different stains

A
  1. Methlene blue - useful for viewing the otherwise nearly invisible nucleus of the cell. (Many living cells are colorless)
  2. Iodine-Potassium Iodide
38
Q

Prokaryotic cells

A
  • Found in the domains Eubacteria and Archaea
  • Lack membrane-bound organelles
  • Contain DNA and ribosomes
  • Most organisms are unicellular
39
Q

Eukaryotic cells

A
  • Found in the domain Eukarya
  • Have membrane-bound organelles, each with its own specific structure and function.
  • Most organisms are multi-cellular, with one large exception being the protists.
40
Q

Similarities of prokarytoic cells and eukaryotic cells

A
  • Both contain DNA and ribosomes
41
Q

Differences of prokarytoic cells and eukaryotic cells

A
  • Eukaryotic cells have membrane-bound organelles and are multi-cellular
42
Q

Kingdoms of eukaryotic cells

A
  • Animalia
  • Plantae
  • Protista
  • Fungi
43
Q

Animal kingdom

A
  • Animalia

- Eukarya domain

44
Q

Plant kingdom

A
  • Plantae
  • Eukarya domain

Tissues include:

  • Epidermal tissue: Epidermis
  • Ground tissue: Palisade parenchyma
  • Vascular tissue: Vein
45
Q

Epidermal tissue

A
  • Epidermis
  • Protective layer may contain specialized cells (guard cells) that function to open and close pores in the leaves (stomata). These pores allow gas exchange and are found on the undersurface of leaves.
46
Q

Ground tissue

A
  • Palisade parenchyma
  • The upper most layer contains the cells that are actively involved in photosynthesis. These cells contain chloroplasts.
47
Q

Vascular tissue

A
  • Vein

- Contain both xylem and phloem cells

48
Q

Protists kingdom

A
  • Protista
  • Eukarya domain
  • unicellular
49
Q

Fungi kingdom

A
  • Fungi
  • Eukarya domain
  • Often filamentous
  • Cell wall made of chitin that surrounds their cell membrane.
  • Reproduce by releasing spores
50
Q

Bacteria Kingdom

A
  • Eubacteria
  • Prokarya domain
  • The only non-membrane bound organelle they contain is the ribosome, which cannot be seen with a light microscope. Due to their small size, bacteria are difficult to view with the light microscope.
51
Q

Biohazardous

A

Biological substances that pose a threat to the health of living organisms, primarily that of humans.

Bio 196 L (9 decks)

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