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BIO111: Microbiology > Lab Practical 1 > Flashcards

Flashcards in Lab Practical 1 Deck (52):
0

Why is the microscope called a compound light microscope?

The term light refers to the method by which light transmits the image to your eye. Compound deals with the microscope having more than one lens. Microscope is the combination of two words; "micro" meaning small and "scope" meaning view

1

Why are most college campuses equipped with compound light microscopes?

*

2

SCAN power

4x
total 40x

3

LOW power

10x
100x total

4

HIGH power

40x
400x total

5

Oil immersion

100x
1000x total

6

distance between the slide and the lens is called

working distance

7

magnificaion

the apparent increase in size of an object

8

total magnification

ocular power multiplied by objective power

9

located on the stage; this allows light from the lamp to penetrate the stage and illuminate the specimen

Aperture

10

What controls the amount of contrast the microscope specimen has

condenser and iris diaphragm

11

Which way do you move the diaphragm level to make the specimen darker

Right

12

Field of View

the area visible through the eyepiece

13

Most stains are charged.....

positive

14

Parfocal

the ability for an object to stay in relative focus when changing objectives

15

Why is oil used on oil immersion?

To decrease light refractivity entering the specimen.

16

Resolution

the fineness of detail that can be examined using a scope, the better the resolution the greater amount of detail that can be examined

17

What unit of measurement is usually used for measuring the size of cells

micrometer

18

Field of view SCAN

4.5 mm

19

field of view LOW

1.8 mm

20

field of view HIGH

0.45 mm

21

Field of view for OIL IMMERSION

0.18 mm

22

To determine average diameter of a cell

1. Count # of cells that fit strait across field
2. Estimate the size of cells by dividing field of view in mm by the number of cells that fit across the field of view.
3. Convert number to micrometers by moving decimal point to the right 3 places

23

Protozoans

Protists
Single Cell
Motile

24

3 ways protoza move

Psudopodia
cilia
flagella

25

flagellated algae

protists
single cells
green
motile

26

filamentous algae

protists
cells from chains
non-motile
green

27

nonfilamentous and nonflagellated algae

protists
single cells
green
nonmotile

28

invertebrates

animals
large
multicellular
motile
(mosquito larve, rotifer)

29

diatoms

usually very detailed with 2 parts connected together

30

S.epidermidis

clusters of spheres

31

B. megaterium

chains of rods

32

negative stain

nigrosin or India ink (acidic) is placed on the slide and the bacteria is mixed into it and then spread out in a thin layer and allowed to air dry.
The stain in anionic so it stains the background rather than the cells.

33

Benefit of negative staining over simple or differential staining is...

there is no heat fixation needed which can shrink the cells.

34

Reason for heat fixing

to ensure cells are adhered to the slide so they aren't washed off during staining and rinsing
and to ensure cell shrinking happens before staining so it doesn't happen during staining which could result in distortion and artifacts

35

Simple Stain

positive charge (basic)
Bacteria is stained bluish purple by the methylene blue

36

Gram Stain

a differential stain
Primary Stain - Crystal Violet (20 seconds)
Mordant - Gram's Iodine (1 minute)
Decolorization - Ethyl Alcohol (10 -20 seconds)
Counter stain - Safranin (1 minute)
*rinse with H20 for 2 seconds between each step and blot dry when finished

37

Gram+

Stained bluish purple by crystal violet
(B.megaterium & S. epidermis & S. aureus)

38

Gram -

stain pinkish red
(s. marcesens & E.coli)

39

Acid fast stain

Differential stain
presence of mycobacterium (rod shaped w. special lipids in cell wall that are hard to stain - mycolic acid)
+ red - blue

40

2 different methods of acid fast stain

Ziehl Neelson method (same as Kinyoun but uses heat after phenol)
Kinyoun Method

41

Acid fast staining method

Primary - Carbolfuschin (red) - 5 minutes rinse w. water
Mordant - heat or chemical concentration
Decolorant - Acid-Alcohol (1 minute) rinse with water to stop
Counterstain - Methylene blue - 30 seconds
DO NOT BLOT DRY

42

Why is phenol important in acid fast staining

it is able to penetrate the wall of the mycobacterium so they can be stained.

43

Acid fast positive

Red/pink in color
ex. M. smegmatis

44

Acid fast negative

stained blue/purple in color
ex. S.epidermis S.aureus

45

Endospore stain

Stains endospore
Vegetative cell is Red
Endospore is Green (pale)

46

Method of endospore staining

Schaeffer-Fulton Method
heat is applied to ensure malachite green can adhere/penetrate the tough outer coating of the endospore

47

3 locations of endospores

Central, Terminal, and lateral

48

Why is knowing if endospores are present and their size and location important to a microbiologist?

It helps them identify what bacteria the endospore is from

49

Euglena

a photosynthetic protist
Green
motile

50

Yeast

show Brownian movement but not motile
grayish white in color look like long jelly beans

51

types of flagellar arrangement

monotrichous
lophotrichous
peritrichous
amphitrichous