Labs 1-4 Flashcards Preview

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Flashcards in Labs 1-4 Deck (32):
1

Compound Light Microscope

An instrument that uses light and multiple lenses to magnify objects/view specimens

2

Magnification

The apparent increase in the size of an object

3

Light Switch/Light Intensity Knob (Dimmer)

Turn the lamp on/off and control brightness; the higher the magnification, the more light is needed

4

Ocular Lens

Magnify by 10X; pointer in the right lens; must be adjusted for your inter-eye distance

5

Objective Lenses

4 lenses with increasing powers of magnification:
- Scanning Lens 4X
- Low Power Lens 10X
- High Power Lens 40X
- Oil Immersion Lens 100X

6

Working Distance

The distance between an objective lens and the slide being viewed

7

Total Magnification

Ocular power multiplied by objective power
- TM (using scanning lens) = 10 (ocular) X 4 (scan) = 40X magnification

8

Condenser and Iris Diaphragm Lever

Controls the amount of contrast that the microscopic specimen has; moved right - field of view gets darker/more contrast; moved left - field of view gets brighter and clear cells become more difficult to see, but colors (stains) are brighter

9

Contrast

The difference in intensity between two objects or between an object and its background

10

Mechanical Stage

Horizontal platform that supports the microscope slide

11

Mechanical Stage Knobs

Move slide into correct position

12

Stage Clips

Fasten slide to the stage

13

Field of View

The area visible through the eyepiece

14

Coarse Focus Adjustment

Moves the stage up and down quickly; changes working distance and brings slide into focus; should only be used when using scanning power objective lens

15

Fine Focus Adjustment

Moves the stage up and down slowly; changes working distance and brings slide into focus; should be used to focus the specimen on low, high, and oil immersion

16

Nosepiece

Holds objective lenses and rotates them into position over the slide

17

Parfocal

An image will remain in focus when changing from a lower-power objective lens to a higher-power objective lens, with little focusing necessary with the fine focus adjustment

18

Immersion Oil

Decreases light refractivity entering the specimen; at high magnifications, light refractivity leads to poor resolution and blurry images; only a single drop is necessary on the area being examined

19

Resolution

The fineness of detail that can be examined using a scope

20

Micrometer (um)

The unit used to measure field of view or the size of cells; 1/1000 of a millimeter

21

Field of View Measurements

- Scan: 4.5 mm
- Low: 1.8 mm
- High .45 mm
- Oil Immersion: .18 mm

22

Average Diameter of Cells

Field of view divided by the number of cells across the field of view; to convert to um, multiply by 1000 or move the decimal point three places to the right

23

Protozoans

Protists, single-celled, motile

24

Flagellated Algae

Protists, single cells, green, motile

25

Filamentous Algae

Protists, cells form chains, green, motile

26

Nonfilamentous and Nonflagellated Algae

Protists, single cells, green, non-motile

27

Invertebrates

Animals, large, multicellular, motile

28

Aseptic Techniques

Procedures used to reduce the number (or kill) of microbes on a surface to prevent contamination; ex.: disinfection, flaming

29

Negative Stain (Smear Stain)

Useful procedure for studying the morphology of bacterial cells and characterizing some of the external structures that are associated with them; cells appear as transparent objects against a dark background

30

Negative Staining Procedure

Consists of mixing the organism with a small amount of stain (india ink or nigrosin) and spreading a very thin film over the surface of the microscope slide

31

Spirochaetes

Very thin cells that do not stain well with positive stains

32

Reasons for Conducting a Negative Stain

- Quick
- Determine morphology (shape and size)
- To view external features
- No heat fixation: no cell shrinkage or distortion and determination of size is more accurate
- Possible to view spirochaetes