Microbio Lab Practical #1

what is 1

Ocular/Eyepieces

What is 2

Body tube

What is 3

Nose piece 

What is 4

Condenser Lens

What is 5

Objective lenses

What is 6

Coarse knob

What is 7

Fine knob

What is 8

Stage

What is 9

Illuminator

What is 10

Iris Diaphragm

Nosepiece function

revolves and contains the objectives 

Ocular/Eyepieces function

what you view through

Body tube function

Houses the lens system that magnifies the specimens

Ethanol class

Alcohol

mouthwash class

Quaternary ammonium

Bleach class

Halogen

Hydrogen peroxide class

Oxidizing agent

Stage function

a platform used to place the slide with a hole in the center to let light from the illuminator pass through.

Iris diaphragm function

regulates the amount of light entering the lens system.

Condenser lens function

a two-lens system that collects and concentrates light from the illuminator and directs it to the iris diaphragm

Illuminator function

the light source in the base of the microscope.

Coarse function

moves stage closer or further away from objective lenses

Fine knob function

sharpens image of specimen

What is the total magnification for 4x

40x

What is the total magnification for 10x

100x

What is the total magnification for 40x

400x

What is the total magnification for 100x

1000x

Which focus knob(s) should you use with the 4x objective?

Coarse and fine knobs

Which focus knob(s) should you use with the 10x objective?

only fine knob

Which focus knob(s) should you use with the 40x objective? 

only fine knob

Which focus knob(s) should you use with the 100x objective?

only fine knob

If you are unable to focus at the 40x, what should you do?

make sure slide is not upside down and clean objective lens

Sould you just skip ahead to the 100x, if you cant focus at 40x?

No, if its not clear at 40x, it won’t be at 100x

What do you need to add when transitioning from the 40x to 100x objective lens?

Immersion Oil

Describe how to use the par-focal nature of your microscope when observing a sample?

first focus on the specimen at the lowest magnification using the coarse focus knob. Then, center the specimen in your field of view before switching to a higher power objective and only make fine adjustments after

What is the purpose of adding oil when using the 100x objective lens?

to increase magnification clarity and resolution by minimizing light refraction

How do you properly carry a microscope?

One hand on handle, one hand supporting base

What kind of paper do you use to clean oil off a microscope lens?

Lens paper

How do you properly store a microscope?

in cabinets with stage all the way down, 4x objective lens, no oil, oculars facing the back of the cabinet with their dust cover put back on

Identify shape

Cocci

Identify arangement

chain-like

identify shape

Bacillus

identify arragement

diplococci or in pairs

Identify arrangement

clusters

Identify arrangement

tetrad

What tool should be used to inoculate a plate?

Inoculation loop

Do you use the loop immediately after taking it out the incinerator

No, wait for it to cool off or it can kill the bacteria

All cultures must be properly labeled with

Name, date, section, and culture

Should you keep culture tubes open even when not in use

no, close them

Which micropipette would you use to transfer 12 μL?

20 microliter pipette

Which micropipette would you use to transfer 198 μL?

200 microliter pipette

Which micropipette would you use to transfer 300 μL? 

1000 microliter pipette

What volume is this pipette transfering

13.6 microliters

What volume is this pipette transfering

198 microliters

what volume is this pipette transfering

950 microliters

How should your plates be stored?

Upside down

What is a pure culture

laboratory culture containing only one species of microorganism, free from other organisms

What would the result be if you were culturing an agar plate and forgot to let the

inoculating loop cool between sections 2 and 3?

No isolated colonies just culture spread all around

Where do you label on your plate?

At the bottom of plate

Where do you label on your tube?

on the tube, not the cap

purposes of heat-fixing a slide

so it can kill bacteria, smear can stick, and retain stains better

What happens if you heat fix a slide before drying it

the smear will boil

What could happen if you overheat the slide during the heat-fixing

process?

The slide can break

could happen if you underheat the slide during the heat-fixing

process?

cells might wash off during staining

How does the gram-staining differ when making a smear from a solid culture vs. a

liquid culture

from a solid culture you need to add 20-25 microliters of DI water

What is the term for the liquid used to promote primary stain retention in a

gram stain?

mordant

Crystal violet

primary stain

Iodine

mordant

Ethanol

Decolorizer

Safranin

counterstain

Purple gram stain

Gram Positive

Pink gram stain

Gram Negative

What is the difference between direct and indirect quantitation?

Direct quantitation measures a quantity directly with an instrument and Indirect quantitation calculates or estimates a value using a known relationship with another

CNA stands for

Colistin and Nalidixic Acid

Columbia CNA Agar

Selective, Differential, and Enriched

Columbia CNA agar selective ingredients

Colistin and Nalidixic Acid

Columbia CNA agar selective for

gram positive bacteria

Columbia CNA agar differential ingredients

hemolysins

Columbia CNA agar enriched ingredients

blood

MAC agar is called

MacConkey Agar

MacConkey Agar

Selective and differential

MacConkey agar selective ingredients

Crystal violet and bile salts

MacConkey agar is selective for

gram negative bacteria

MacConkey agar differential ingredients

Lactose Carbohydrate and pH indicator

If bacteria ferments lactose on a MacConkey agar plate, what color will it be

Pink

MSA agar stands for

Mannitol Salt Agar

MSA agar

Selective and differential

MSA agar selective ingredients

high concentrations of NaCl

MSA agar differential ingredients

mannitol (sugar alcohol) and pH indicator

If bacteria ferments mannitol on a MSA plate what color will it be

Yellow

What plate does not have any selective, differential or enriched ingredients

Mueller-Hinton agar

greenish-gray or greenish yellow on a blood agar plates means

alpha hemolysis

clearing on a blood agar plate means

beta hemolysis

no change on a blood agar plate means

non-hemolytic, gamma

BEA agar 

selective and differential

BEA agar selective for

Streptococcus and enterococcus bacteria

BEA agar differential ingredients

bile esculin

If bacteria hydrolizes bile esculin what happens

turns black

Carbohydrate metabolism is more

acidic

protein metabolism is more

basic