Microbiology Exam 1 Chapter 2

Front 1

bright-field microscope

Back 1

a scope that illuminates the speciment directly with bright light and forms a dark image on a brighter background

Front 2

confocal scanning laser microscope (CSLM)

Back 2

laser light scans across specimen, one area at a time, excellent contrast and resolution.

Front 3

dark field microscope

Back 3

brightly illiminates the specimen and leaves background black

Front 4

differential interference contrast microscopy

Back 4

combines two beams of plane polarized light after passing through a specimen; interference is used to create the image

Front 5

differential staining

Back 5

procedure that microbes into separate groups based on staining properties

Front 6

fixation

Back 6

internal and external structures of a cell are preserved and fixed into position.

Front 7

fluorescence microscopy

Back 7

exposes specimen to a light of a specific wavelenghth and then forms an image from the fluorescent light produced. Specimen stained with fluorescent dye

Front 8

Gram stain

Back 8

differential staining procedure that divides bacteria into gram+ and gram - groups based on ability to retain crystal violet when decolorized with an organic solvent like ethanol

Front 9

negative staining

Back 9

dye is used to make the background dark while the specimen remains unstained.

Front 10

parfocal

Back 10

retains proper focus when objectives have changed.

Front 11

phase contrast microscope

Back 11

converts slight differences in refractive index and cell density into easily observed differences in light intensity.

Front 12

refractive index

Back 12

a measure of how much a substance deflects a light ray from a straight path as it passes from one (glass) medium to another (air)

Front 13

resolution

Back 13

the ability of a microscope to separate or distinguish between small objects that are close together.

Front 14

scanning electron microscope

Back 14

an electron microscope that scans a beam of electrons over the surface of the specimen and forms an image of the surface from the electrons that are emitted by it.

Front 15

scanning probe microscope

Back 15

a microscope used to study surface features by moving a sharp probe over the objects surface.

Front 16

simple staining

Back 16

staining a specimen with a simple dye

Front 17

transmission electron microscope

Back 17

an image is formed by passing an electron beam through a specimen and focusing the scattered electrons with magnetic lenses.

Front 18

Cell characteristic

Back 18

Cells are mainly water and do not absorb much light - staining makes them visible.

Front 19

Visibility of cell

Back 19

based on absorption or refraction of light - colored cells absorb a lot of light

Front 20

staining

Back 20

usually kills cells