Lab Practical 1

Question 0

Why are most college campuses equipped with compound light microscopes?

Answer 0

*

Question 1

Why is the microscope called a compound light microscope?

Answer 1

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

Question 2

SCAN power

Answer 2

4x

total 40x

Question 3

LOW power

Answer 3

10x

100x total

Question 4

HIGH power

Answer 4

40x

400x total

Question 5

Oil immersion

Answer 5

100x

1000x total

Question 6

distance between the slide and the lens is called

Answer 6

working distance

Question 7

magnificaion

Answer 7

the apparent increase in size of an object

Question 8

total magnification

Answer 8

ocular power multiplied by objective power

Question 9

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

Answer 9

Aperture

Question 10

What controls the amount of contrast the microscope specimen has

Answer 10

condenser and iris diaphragm

Question 11

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

Answer 11

Right

Question 12

Field of View

Answer 12

the area visible through the eyepiece

Question 13

Most stains are charged…..

Answer 13

positive

Question 14

Parfocal

Answer 14

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

Question 15

Why is oil used on oil immersion?

Answer 15

To decrease light refractivity entering the specimen.

Question 16

Resolution

Answer 16

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

Question 17

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

Answer 17

micrometer

Question 18

Field of view SCAN

Answer 18

4.5 mm

Question 19

field of view LOW

Answer 19

1.8 mm

Question 20

field of view HIGH

Answer 20

0.45 mm

Question 21

Field of view for OIL IMMERSION

Answer 21

0.18 mm

Question 22

To determine average diameter of a cell

Answer 22

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

Question 23

Protozoans

Answer 23

Protists
Single Cell
Motile

Question 24

3 ways protoza move

Answer 24

Psudopodia cilia flagella

Question 25

flagellated algae

Answer 25

protists single cells green motile

Question 26

filamentous algae

Answer 26

protists cells from chains non-motile green

Question 27

nonfilamentous and nonflagellated algae

Answer 27

protists single cells green nonmotile

Question 28

invertebrates

Answer 28

``` animals large multicellular motile (mosquito larve, rotifer) ```

Question 29

diatoms

Answer 29

usually very detailed with 2 parts connected together

Question 30

S.epidermidis

Answer 30

clusters of spheres

Question 31

B. megaterium

Answer 31

chains of rods

Question 32

negative stain

Answer 32

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.

Question 33

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

Answer 33

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

Question 34

Reason for heat fixing

Answer 34

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

Question 35

Simple Stain

Answer 35

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

Question 36

Gram Stain

Answer 36

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

Question 37

Gram+

Answer 37

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

Question 38

Gram -

Answer 38

stain pinkish red | s. marcesens & E.coli

Question 39

Acid fast stain

Answer 39

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

Question 40

2 different methods of acid fast stain

Answer 40

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

Question 41

Acid fast staining method

Answer 41

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

Question 42

Why is phenol important in acid fast staining

Answer 42

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

Question 43

Acid fast positive

Answer 43

Red/pink in color | ex. M. smegmatis

Question 44

Acid fast negative

Answer 44

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

Question 45

Endospore stain

Answer 45

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

Question 46

Method of endospore staining

Answer 46

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

Question 47

3 locations of endospores

Answer 47

Central, Terminal, and lateral

Question 48

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

Answer 48

It helps them identify what bacteria the endospore is from

Question 49

Euglena

Answer 49

a photosynthetic protist Green motile

Question 50

Yeast

Answer 50

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

Question 51

types of flagellar arrangement

Answer 51

monotrichous lophotrichous peritrichous amphitrichous