Lab Exam

Question 1

Stage

Answer 1

Fixed platform with an opening in the center allowing for passage of light from illuminating source to lens system

Question 2

Mechanical stage

Answer 2

Can be moved vertically or horizontally by means of adjustment controls.

Question 3

Illumination

Answer 3

Light source positioned in the base of the instrument

Question 4

condenser

Answer 4

Component directly under the stage contains two sets of lenses that collect and concentrate light

Question 5

Iris diaphragm

Answer 5

Shutter controlled by a lever that is used to regulate the amount of light entering the lens system

Question 6

Body tube

Answer 6

Above the stage, attached to the arm of th microscope’

Question 7

Ocular lens

Answer 7

Eyepiece lens

Question 8

Nosepiece

Answer 8

Moveable, contains objective lens

Question 9

Coarse adjustment and fine adjustment knobs

Answer 9

Below stage

Question 10

Magnification

Answer 10

Enlargement of a specimen using a two lens system: ocular and objective

Question 11

Objective produces what kind of image?

Answer 11

Real image

Question 12

Ocular lens produces the

Answer 12

Final image

Question 13

Resolving power

Answer 13

How far apart two adjacent objects must be before a given lens shows them as discrete entities. When two objects look as one, the resolution has been lost

Question 14

Numerical aperture

Answer 14

Function of the diameter of the objective lens in relation to its focal length. RP=wavelength of light/2x numerical aperture

Question 15

refractive index

Answer 15

The bending power of light passing through air from the glass slide to the objective lens

Question 16

As the magnification of the lens increases,

Answer 16

The working distance decreases and the numerical aperture of the objective lens increases

Question 17

Parfocal

Answer 17

When one lens is in focus, others will also have the same focal length

Question 18

Heat fixation

Answer 18

Rapid movement of specimen over flame fixing to the slide

Question 19

Sub culturing

Answer 19

Transfer of organism from one medium to another

Question 20

Pure culture

Answer 20

Containing only one specimen

Question 21

Uniform fine turbidity

Answer 21

Finely dispersed growth throughout

Question 22

Flocculent

Answer 22

Flakey aggregates dispersed throughout

Question 23

Pellicle

Answer 23

Thick pad like growth on surface

Question 24

Sediment

Answer 24

Concentration of growth at the bottom of broth culture may granular, flaky or flocculent

Question 25

Crateriform

Answer 25

Liquefied surface is saucer-shaped

Question 26

Stratiform

Answer 26

Complete liquefaction of the upper half of the medium

Question 27

Simple staining

Answer 27

Stained with single reagent: methylene blue, crystal violet and carbon fuchsin

Question 28

Diplo

Answer 28

Pair

Question 29

Strepto

Answer 29

Chain

Question 30

Staphlyo

Answer 30

Cluster

Question 31

Tetrad

Answer 31

4

Question 32

Sarcina

Answer 32

Packet of 8

Question 33

Vibrios

Answer 33

Curved rod

Question 34

Spirilla

Answer 34

Helical and rigid

Question 35

Spirochetes

Answer 35

Helical and flexible

Question 36

Negative staining

Answer 36

Requires use of acidic stain - cells remain discernible to the background

Question 37

Differential Staining

Answer 37

Use of at least four chemical reagents

Question 38

Primary stain

Answer 38

Impart color to cells | Crystal Violet

Question 39

Secondary stain

Answer 39

Intensifies color Gram's iodine

Question 40

Third stain

Answer 40

Decolorizing agent Alcohol

Question 41

Counterstain

Answer 41

Fourth stain; has contrasting color to the primary stains Safranin

Question 42

Gram +

Answer 42

Purple

Question 43

Gram -

Answer 43

Red

Question 44

The best gram stains are made with cultures that are

Answer 44

Less than 24 hours old

Question 45

Types of acidic dyes

Answer 45

Sodium eosinate India ink Nigrasine

Question 45

Negative stain

Answer 45

Indirect stain that colors the background due to polarization of ions in cell coat and pigment Color is in the negative ion

Question 45

Positive stain

Answer 45

Color is in the positive ion.... basic dyes

Question 45

False gram reaction

Answer 45

Looks one way but is actually another False gram+ Smear is too think Specimen was not fully decolorized False gram - Over decolorized Over heat fixed Bacteria older than 24 hours

Question 45

Micrococcus luteus

Answer 45

Gram + Cocci in tetrads Yellow colonies on agar plate

Question 45

Escherichia coli

Answer 45

Bacillus No cell arrangement Gram - White colonies

Question 45

Serratia marcescens

Answer 45

Gram - Bacillus no arrangement Pink red colonies at 25 degrees celsius White colonies at 37 degrees Difference in color indicates activity of the pigment gene due to temperature differences

Question 46

Advantages of hanging drop

Answer 46

Can observe life processes such as motility, cell division, phagocytosis, Distortion of cells Observation of cells that stain poorly or not at all

Question 47

Advantages of acidic dyes

Answer 47

No distortion of cells since there is no heat fixing of the slide Can observe orgs that stain poorly or not at all

Question 48

True motility

Answer 48

Has directional movement with purpose

Question 49

Brownian movement

Answer 49

Stationary bouncing caused by random collisions