Lab 1

Question 1

Whats the nomenclature for S. aureus

Answer 1

Staphylococcus aurues (italized, second word isnt capitalized)

Question 2

Whats staphylococcus

Answer 2

in clusters (grape like)

Question 3

Whats streptococcus

Answer 3

chains

Question 4

Whats nuemerical aperture

Answer 4

measure of the lightgathering ability of a lens

Question 5

Purpose of using immersion oil

Answer 5

the numerical
aperture of the lens increases,
improving the resolution of the microscope.

As light rays move through the specimen,
through the oil (as opposed to air) there is less refraction and thus more light will enter
the objective lens allowing this increase in resolution

Question 6

Stage micrometer major division length

Answer 6

100 micrometers apart

Question 7

Smallest divisions in stage micrometer

Answer 7

10 micro meters apart

Question 8

Ocular micrometer has numbers

Answer 8

yes

Question 9

Stage micrometer has numbers

Answer 9

no

Question 10

30 OU is measured to be 200 micro meters. 1 OU is

Answer 10

200/30 = 6.67 um

Question 11

As magnification incrases

Answer 11

the value of ocular micrometer divisions will decrease

Question 12

What do stains contain

Answer 12

a coloured molecule called a chromogen.

Question 13

What do chromogens contain

Answer 13

a chromophore (gives the color)
and auxochrome (portion that forms an ionic or cvalent bond)

Question 14

A basic stain is — charged

Answer 14

positive charged -> can bind to negatively charged cell surface

Question 15

A acidic stain is — charged

Answer 15

negatively charged -> background is stained and cell is colorless

Question 16

Purpose of heat fixation

Answer 16

1) To kill the bacterial cells
2) Coagulate the cytoplasmic proteins to make them more visible
3) Help cells adhere to the slide

Question 17

Downside of heat fixation

Answer 17

Can distort the cell to some degree causing shrinkage

Question 18

Before you start staining, what must you do

Answer 18

Clean slides with 95% ethanol

Sterilizae inoculating loop

Cool inoculating loop

Question 19

If you are preparing a bacterial smear from a slant (solid culture)

Answer 19

spirt a drop of H2O

Question 20

Before staining you must,

Answer 20

Air dry the smear

Heat fix the bacteria

Question 21

Process of staining

Answer 21

1. Aspectically add the bacterial smear until approx size of a nickel and slimmer consistency than milk
2. All smear to air dry
3. Heat fix
4. Place on rack, apply stain
5. Rinse of dH2O
6. Dry with bibulous paper
7. View and see

Question 22

What are some primary stains

Answer 22

Crystal violet

Safranin

Methylene Blue

Question 23

What is the negative stain

Answer 23

• used with an acidic stain which is repelled by the
  negatively charged bacterial cell surface
• The background becomes stained, and the cell
  appears white (unstained)

-

Question 24

When should you not heat fix

Answer 24

• Negative staining
• Capsule stain
• Hanging drop (keep cells alive)

-> bc heat fixing can distort and shrink the cell

Question 25

Whats an acidic/negative stain

Answer 25

Nigrosine

Question 26

Whats the procedure for negative staining

Answer 26

1. Add 1 drop of Nigrosine to one side of the slide 2. Using the inoculating loop, transfer a small amount of 1 culture to the drop of stain. Mix stain with culture and loop 3. Place second clean glass side and spread the mixture across 4. Allow to air dry. 5. Do not heat fix 6. Observe under light microscope, look for regions where the nigrosine is not too thick

Question 27

When are cells truly motile

Answer 27

When they possess a single flagellum or flagella

Question 28

When are cells nonmotile

Answer 28

They exhibit brownian motion. They vibrate in their spot due to bombardment of water molecules in their enviornment.

Question 29

Do u heat fix cells in hanging drop?

Answer 29

No, need them to be alive

Question 30

Is E. coli motile

Answer 30

Yes

Question 31

Is Staphylococcus epidermidis motile

Answer 31

No. Its non-motile: brownian motion

Question 32

Procedure for flagella

Answer 32

1. Obtain depression slide. Obtain glass cover slide 2. If using solid (must put 1 drop of water on slide first, liquid: can put direectly on top of it) 2. apply petroleum jelly on the depression 5. incert depression and place on top of the cover slide

Question 33

How long can flagella be

Answer 33

several times longer than the bacteria cell

Question 34

Problem with flagella

Answer 34

Too thin to be observed with the light microscope and basic staining techniques

Question 35

Whats a mordant

Answer 35

e of a mordant so that the stain adheres in layers to the flagella, allowing visualization. In other words, the mordant is used to enhance the thickening of the stain around the flagella so it can be seen

Question 36

Procedure for flagella staining

Answer 36

Involves using a wet mount of the motile bacteria and drying the slide for 10-15 minutes, then applying the Ryu stain (mordant) using a syringe under the cover slip

Question 37

Whats the mordant used for flagella stianing

Answer 37

Ryu stain

Question 38

Whats monotrichous

Answer 38

Single flagellum at one end of the cell

Question 39

Whats amphitrichous

Answer 39

flagella at both ends

Question 40

Whats lophotrichous

Answer 40

tufts of flagella at the end of the cell

Question 41

Whats peritrichous

Answer 41

Flagella emerging from entire cell surface