Biol 1115: Lab Midterm Section 1

Front 1

Dissecting Microscope

Back 1

Operates by light passing through specimen and lenses magnify image. Can magnify an object up to 2,500 times is original size. Resolution of 0.2 micrometers or 0.4 micrometers without oil.

Front 2

Compound Microscope

Front 3

Scanning Electron Microscope

Back 3

Specimen put on small copper grid, coated with thin layer of gold or platinum, and put into this unit in a vacuum. Electron beam bombards the surface of the specimen and scans it back and forth producing an image with 3D detail/ Electrons do not pass through specimen. Can magnify up to 300,000 times and resolution of 0.2nm.

Front 4

Transmission Electron Microscope

Back 4

Specimen stained, dehydrated, and embedded in resin that solidifies it. Sliced very thinly, then put into this unit in a vacuum. Electron beam is passed through and electromagnets are used as lenses to focus and magnify the image. Can magnify up to 300,000 times with a resolution of 0.2nm.

Front 5

Ocular

Back 5

contains magnifying lens (10x).

Front 6

Objective

Back 6

contains lenses to magnify the image

Front 7

Arm

Back 7

used for hand grip of microscope

Front 8

Stage

Back 8

large flat surface that supports the slide

Front 9

Coarse-Focus Knob

Back 9

changes distance from objective lens and specimen

Front 10

Blue Filter

Back 10

increases resolution by reducing wavelength

Front 11

Mechanical Stage

Back 11

holds slide on stage

Front 12

Mechanical Stage Knobs

Back 12

one know moves slide vertically and other horizontally

Front 13

Fine Focus Knobs

Back 13

more precise focusing

Front 14

Condenser

Back 14

contains 2 lenses that focus light onto the specimen

Front 15

Iris Diaphragm

Back 15

regulates amount of light passing through the lenses in the condenser

Front 16

Condenser Adjustment

Back 16

moves condenser up or down

Front 17

Lamp Switch

Back 17

turns light on or off

Front 18

Lamp Intensity Dial

Back 18

adjusts the intensity of light bulb

Front 19

Stage Clips

Back 19

holds slide in position over the stage

Front 20

Main Switch

Back 20

controls supply of power to scope

Front 21

T Switch

Back 21

turns light below a specimen on and off

Front 22

I switch

Back 22

turns light above a specimen on and off

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Parfocal

Back 23

An object in focus at low power will be relatively focused when you switch to medium or high power.

Front 24

Dissecting Microscope: upside down, etc.?

Back 24

Not upside down, moves in the direction that you move it in as well.

Front 25

Compound Microscope: upside down, etc.?

Back 25

Inverted movement and image.

Front 26

1mm = ? micrometers

1m = ? cm

Back 26

1000micrometers

1m = 100cm

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Ocular Lens Magnification

Back 27

10x

Front 28

Objective Lens Magnification for Dissecting Microscope

Back 28

Low Power: 2x

High Power: 4x

Front 29

Objective Lens Magnification for Compound Microscope

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Low power 4x

Medium Power 10x

High Power 40x

Oil Immersion 100x

Front 30

Total Magnification Calculations

Back 30

Ocular Lens (10x) * Objective Lens

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Measure of Size of Specimen

Back 31

Indirect Measurement: field diameter * estimated fraction of specimen = x mm, then convert to micrometers or other desired units.

Front 32

Measure of Speed of Specimen

Back 32

Amount organism moved / time it took. Then multiply this number by 60 seconds.

Front 33

Magnification of Drawing

Back 33

size of drawing (mm) / actual size of specimen (mm).

Front 34

Depth of Field

Back 34

The vertical distance that remains in focus at each magnification. As magnification increases, depth of field decreases.

Front 35

Resolution

Back 35

The clarity of an image. The minimum distance that two points or lines can be separated and still be distinguished as separate units.

Front 36

Resolution affected by:

Back 36

Wavelength of light used to produce the microscopic image (blue filter improves it), and by immersion oil. TEM and SEMs allow you to resolve objects 0.2nm apart.

Front 37

Contrast

Back 37

Allows you to make the image stand out better. Contrast can be altered by staining with artificial dyes, using special light microscopes, and reducing light intensity with the light condenser.