Micro Lab Exam 1

Front 1

how to label

Back 1

name, date, medium, inoculum

Front 2

condensor lense

Back 2

concentrates the light and makes illumination of the specimen more uniform

Front 3

resolution

Back 3

clarity of an image

Front 4

limit of resolution or resolving power

Back 4

an actual measurement of how far apart two points must be for the microscope to view them as being separate

Front 5

Numerical aperture

Back 5

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

Front 6

using immersion oil

Back 6

increases numerical aperture; makes limit of resolution smaller = better resolution

Front 7

why calibrate for each magnification?

Back 7

the size of the graduations on the stage micrometer increases as magnification increases. Consequently, the value of ocular micrometer divisions decreases as magnification increases.

Front 8

stains

Back 8

solutions consisting of a solvent (usually water or ethanol) and a colored molecule (often a benzene derivative), the chromogen

Front 9

chromophore

Back 9

the portion of the chromogen taht gives it its color

Front 10

auxochrome

Back 10

the charged portion of a chromogen and allows it to act as a dye through ionic or covalent bonds between the chromogen and the cell.

Front 11

basic stains

Back 11

(where the auxochrome becomes positively charged as a result of picking up a hydrogen ion or losing a hydroxide ion) are attracted to the negative charges on the surface of most bacterial cells.

Front 12

heat fixing

Back 12

kills the bacteria, makes them adhere to the slide, and coagulates cytoplasmic proteins to make them more visible. It also distorts the cells to some extent.

Front 13

negative stain

Back 13

uses a dye solution in which the chromogen is acidic and carries a negative charge (acidic chromogen gives up H); negative charge on bacterial surface repels the negatively charged chromogen so the cell remains unstained against a colored background

Front 14

negative staining used to

Back 14

determine morphology and cellular arrangement in bacteria that are too delicate to withstand heat-fixing. Also, where determining the accurate size is crucial, a negative stain can be used because it produces minimal cell shrinkage.

Front 15

acid fat organisms have what component in their cell wall?

Back 15

mycolic acid; a waxy substance that gives acid-fast cells a higher affinity for the primary stain (red) and resistance to decolorization by an acid alcohol resolution.

Front 16

acid fast negative color

Back 16

blue

Front 17

why stain interacts with cell

Back 17

carbolfuchsin is lipid soluble and penetrates the waxy cell wall. steam heating is used to melt the wax and allow the stain to move into the cell

Front 18

primary stain gram stain

Back 18

crystal violet

Front 19

mordant

Back 19

iodine; to enhance crystal violet staining by forming a crystal violet-iodine complex.

Front 20

counterstain

Back 20

safranin

Front 21

gram negative cell walls

Back 21

higher lipid content (because of the outer membrane) and a thinner peptidoglycan layer; alcohol in the decolorizer extracts the lipid, making the cell wall more porous and incapable of retaining the crystal violet-iodine complex.

Front 22

gram positive cell walls

Back 22

thicker peptidoglycan and greater degree of cross linking (because of teichoic acids) trap crystal violet-iodine complex more effectively.

Front 23

gram positive color

Back 23

violet

Front 24

gram negative color

Back 24

red

Front 25

endospore

Back 25

a dormant form of the bacterium that allows it to survive poor environmental conditions

Front 26

keratin

Back 26

tough outer covering of spores that make them resistant to heat and chemicals

Front 27

vegetative cells and spore mother cells in an endospore stain

Back 27

decolorized with water and counterstained with safranin

Front 28

endospores in an endospore stain

Back 28

stained with Malachite green (water soluble and has low affinity for cellular material so does not stain vegetative and mother cells)

Front 29

spores located in the middle of the cell

Back 29

central

Front 30

spores located at the end of the cell

Back 30

terminal

Front 31

spores located between the end and middle of the cell

Back 31

subterminal

Front 32

flagella stain mordant

Back 32

assist in encrusting flagella with stain to a visible thickness

Front 33

monotrichous

Back 33

single flagellum

Front 34

amphitrichous

Back 34

flagella at both ends of the cell

Front 35

lophotrichous

Back 35

tufts of flagella at the end of the cell

Front 36

peritrichous

Back 36

flagella emerging from the entire cell surface

Front 37

attendance policies

Back 37

-more than 2 absences=incomplete
-3 tardies= unexcused absence

Front 38

filiform growth

Back 38

dense and opaque with a smooth edge

Front 39

friable growth

Back 39

crusty

Front 40

pellicle

Back 40

some organisms float on top of the medium (broth) and produce a type of surface membrane called a pellicle

Front 41

flocculent growth

Back 41

some bacteria appear to clump in what is called flocculent growth (broth)

Front 42

ubiquitous

Back 42

organism can be found just about everywhere

Front 43

free living

Back 43

does not reside on or in a specific plant or animal host and are not known to cause disease

Front 44

opportunistic pathogens

Back 44

capable of producing a disease state if introduced into a suitable part of the body

Front 45

reservoir

Back 45

any area where microbe resides and serves as potential source of infection

Front 46

basic categories of colony morphology

Back 46

1. shape (round, irregular, punctiform)
2. margin (entire, undulate, lobate, filamentous, rhizoid)
3. elevations (flat, raised, convex, pulvinate, umbonate)
4. texture (moist, mucoid, dry)
5. pigment production (color + opaque, translucent, shiny, dull)

Front 47

3 conditions that affect pigment production

Back 47

age, nutrient availability, temperature

Front 48

agar slants useful primarily as

Back 48

media for cultivation and maintenance of stock cultures

Front 49

decontamination

Back 49

-lowest level of control
-reduction of pathogenic microorganisms to a level at which items are safe to handle without protective attire

Front 50

disinfection

Back 50

(low, medium, or high)
-kill large #s of targeted pathogens but typically not large #s of spores
-chemical agents, dry heat, moist heat, UV light
-antiseptics for living tissue

Front 51

sterilization

Back 51

highest level
complete elimination of viable organisms (and spores)
-chemicals, gases, incineration, dry heat, moist heat, ethylene oxide gas, ionizing radiation, low temp plasma or low temp ozone

Front 52

most effective method for sterilization

Back 52

steam (autoclave)

Front 53

biological indicators

Back 53

-test systems that contain something living (like bacterial spores)
-if spores killed in autoclave then no growth
-if not killed, pH indicating dye will reveal any acid produced (so not killed)
-purple= dead
-yellow= alive