Micro Lab Test 3

Front 1

condenser lens

Back 1

concentrates the light and makes illumination of the specimen more uniform

Front 2

refraction

Back 2

bending of light as it bypasses through the objective lens

Front 3

objective lens

Back 3

the microscope lens that first produces magnification of the specimen in compound microscope

Front 4

real image

Back 4

magnified image of a specimen produced by the objective lens of a microscope; the real image is magnified again by the ocular lens to produce the virtual image

Front 5

ocular lens

Back 5

the lens the microscopist looks through; produces the virtual image by magnifying the real image

Front 6

virtual image

Back 6

the image produced when the ocular lens of a microscope magnifies the real image; appears within or below the microscope

Front 7

resolution

Back 7

the clarity of an image produced by a lens; the ability of a lens to distinguish between two points in a specimen; high resolution in a microscope is desirable

Front 8

limit of resolution (or resloving power)

Back 8

the closest two points can be together for the microscope lens to make them appear separate; two points closer than the limit of resoluton will blur together

Front 9

Numerical aperature

Back 9

is a measure of a len's ability to "capture" light coming from the specimen and use it to make the image

Front 10

dark field microscopy

Back 10

a special condenser is used so only the light reflected off the specimen enters the objective. The appearance is of a brightly lit specimen against a dark background and often with better resolution than that of the britht-field microscope

Front 11

phase contrast microscopy

Back 11

uses florescent dye that emits fluorescent when illuminated with ultraviolet radiation

Front 12

contrast

Back 12

to be visible the specimen must contrast with the background of the microscope field

Front 13

morphologies

Back 13

the shape of an organism

Front 14

spirilla

Back 14

spiral shaped cell

Front 15

cocci

Back 15

spherical shaped cell

Front 16

bacilli

Back 16

rod shaped cell

Front 17

vibroios

Back 17

slightly curved rod sshaped cells

Front 18

coccobacilli

Back 18

short rod shaped cells

Front 19

spirochetes

Back 19

flexible spiral shaped cells

Front 20

plemorphic

Back 20

a variety of cell shapes

Front 21

diplococcus

Back 21

two spherical cells attached

Front 22

diplobacilli

Back 22

two rod shaped cells that are attached

Front 23

streptobacillus

Back 23

a chain of rod shaped cells

Front 24

tetrad

Back 24

(tetra=4)"x" shaped cell formations (only in cocci cells)

Front 25

sacina

Back 25

a cube shaped arrangement of eight cells (only in cocci cells)

Front 26

staphylococcus

Back 26

a cluster of cells

Front 27

surface to volume ratio

Back 27

when a cell reaches a size that cannot adequately supply the nutrient needs of its cytoplasm

Front 28

chromogen

Back 28

a colored molecule

Front 29

chromophore

Back 29

the charged region of a dye molecule that give it its color

Front 30

auxochrome

Back 30

the charged portion of a chromogen that allow it to act

Front 31

basic stains (alkaline)

Back 31

where the auxochrogen becomes positively charged as a result of picking up a hydrogen ion or losing a hydroxide ion) they are attracted to the negative charges on the surface of most bacterial cells, thus coloring the cells

Front 32

heat fixed

Back 32

kills the bacteria making them adhere to the slide and coagulates cytoplasmic proteins to make them more viable, it also distorts the cells to some extent

Front 33

negative stain

Back 33

an acidic chromogen gives up a hydrogen ion, which leaves it with a negative charge, the negative charge is repelled by negatively charged bacteria which only allow the background to be stained

Front 34

differential stains

Back 34

allow microbiologists to detect differences between organisms or differences between parts of the same organism, the gram stain is the most common

Front 35

structural stains

Back 35

other differential stains used for organisms not distinguishable by the gram stain and for those that have other important cellular attributes, such as a capsule, spores, or flagella

Front 36

decolorization

Back 36

gram stain step that occurs between the application of two basic stains (most critical stop) removes primary stain from gram negative cells are decolorized by the solution (usually alcohol or acetone)

Front 37

primary stain

Back 37

used gram stain and is crystal violet

Front 38

mordant

Back 38

used in gram staining to enhance crystal violet staining (crystal violet-iodine complex)

Front 39

counter stain

Back 39

final step in gram stain procedure, it colors the gram negative cells. Upon completion the gram poitive cells appear purple and gram negative cells appear reddish-pink

Front 40

Steps for gram staining

Back 40

heat fix emulsion, cover the smear with crystal violet, gently rinse with distilled water, cover the smear with iodine stain, gently rinse with distilled water, decolorize, counter stain