Microm 302 Quiz 1

UW

Where is the closest fire extinguisher?

front of lab, by the door to the inner hallway

Where is the closest eye wash?

at the front sink

Where is the closest safety shower?

in the inner hallway

Where can you access aditional safety info?

• in the computer in the inner lab

• on 302 Canvas, under "link to lab safety manual"

Why should proper aseptic technique be used when handling microorganisms?

• to prevent contaminating yourself

• to prevent contaminating the environment

New car

• to prevent contaminating the environment

• to prevent contaminating other individuals

Where should you dispose of ubiquity plate/larger disposables with microbial growth? (disposables)

large orange bag in the bin at the front of lab

Where should you dispose of a pipette to transfer bacteria?

small bins with orange bags on benches without the wrapper it came in (regular trash)

Where should you dispose of the paper towel used to disinfect the benches? (anything not contaminated)

regular trash

How should the bunsen burner be when actively streaking out a bacterial culture?

on full flame

How should the bunsen burner be when not actively using flame, but maybe later?

on pilot light

Why should you disconnect the bunsen burner hose when you're done?

• ensure gas jet is off

• make sure no gas in tubing

• to prevent fires if leaking

• instructor can quickly check it's off

What prevent aerosol formation in lab?

• start flaming loop near handle to the end of the loop

• wait for loop to cool before using on culture

Why do you wipe off oil off 100x lens?

otherwise it can gather dust and damage lens

how should microscope be stored?

Remove darkfield, clean any oil off, 4x lens down, stage down, cord around cord holder at the back of the microscope.

What is allowed on top of the bench?

Materials, but never books/backpacks. those cannot be decontaminated

Where are lab coats allowed?

ONLY in lab

Where should you dispose of reusable contaminated items?

Plastic bin by inner hallway door

Where is broken glass discarded of?

in can labeled "broken glass"

Where should contaminated gloves be disposed of?

large orange bag in the bin at the front of lab

When are inoculating loops sterilized?

Before and after each use, with minimal culture on it as not to aerosolize

Where are microbial cultures stored?

in incubators, NEVER in supply bin

What things should be boiled, when, and how?

Wet mounts, but cover slips are disposable to broken glass bin after boiling them for 5-10 mins. this kills any remaining live cultures. A can of cold water can cool the boiling water and then the slides washed and reused.

What do you do if you spill a culture?

Cover with paper towels, soak in disinfectant, soak, remove into broken glass/large orange bag in the bin at the front of lab, wash hands

What is an agar plate?

Petri dish with solidified nutrient. Melts at 100C and solidifies at 45C

What is TSY medium?

Trypticase Soy Yeast - trypticase peptone, soybean enzymatic digest, yest extract, all together are rich in nutrients for microorganisms to grow.

What and where should you label your samples with?

Name, date, sample/experiment on the bottom, not the lid

What temperature is room temperature?

22C

How high can you stack plates?

6 maximum

Why are plates inverted for incubation?

To eliminate condensation which could potentially move the bacteria in a pool of liquid and they won't grow in distinct colonies.

What factors influence bacteria growth?

Nutrient accessibility, environment they grow in (temp, pH, moisture, O2, genetics,etc)

How should you carry a microscope?

Upright and away from your body with one hand on the handle, one underneath the microscope.

What do the ocular lenses do?

Magnify by 10x

What do the objective lenses do?

Magnify 4x, 10x, 40x, 100x on top of the ocular lens

What is the maximum possible magnification?

1000x = 10x(ocular) * 100x(objective)

What does the condenser lens do?

focuses light on specimen

What does the mechanical stage do?

Hold the slide in place

What do the stage adjustment knobs do?

Adjust the mechanical stage back, forth, laterally

What does the iris diaphragm do?

adjusts the amount of light entering the condenser lens and can increase contrast when being closed.

What does the coarse knob focus do and when is it used?

Used to focus image when using 4x or 10x ONLY

What does the fine focus knob do and when is it used?

Used to focus image when using 40x and 100x typically

What does the lamb brightness control dial do?

Controls the microscope lamp brightness

When is the 4x lens used?

Typically isn't since not strong enough to see microorganisms well.

How do you check if what you're looking at is on the slide?

Move the stage using the stage adjustment knobs and if it moves, it is on the slide

What is the width of the pointer body when using the 10x objective lens?

~25 micrometers

What is the width of the pointer body when using the 40x objective lens?

~6 micrometers

What is the width of the pointer body when using the 100x objective lens?

~2.5 micrometers

How small is a micrometer?

1 micrometer = 10^-6 meters = 1/25,600 inches

How big are protozoa in micrometers?

20-100 micrometers

How big is yeast in micrometers?

4-10 micrometers

How big are bacteria in micrometers?

1 micrometer

How big are viruses in micrometers?

0.1 micrometer (too small to see with light microscope)

What does a darkfield stop do?

It increases contrast by darkening the background and illuminating the cultures on the slide

How do you use a darkfield stop?

You insert it on the left side under the stage near the iris diaphragm with "DF" pointing up. Open the iris diaphragm completely and only use 10x and 40x objective lenses.

What is a wet mount?

It is a slide with a diluted culture covered with a cover slip

What is a wet mount used for?

For quickly determining the general organism type and some characteristics

What is a hay infusion?

Collected water with added barley/hay and contain bacteria/protozoa

What is euglena?

It is a motile and photosynthesizing protozoan

What is yeast?

Microscopic fungi that forms in buds and is used to make bread and alcoholic beverages

What is yogurt juice?

Liquid that seeps out of yogurt containing streptococcus thermophilus (sphere) and lactobacillus bulgaricus (rod)

What is the best way to see organisms behind a colorless background?

By increasing the contrast by closing the iris diaphragm

What does parfocal mean?

Once a lens is in focus, the others should be as well or close enough.

What is Brownian motion?

Motion that looks like random vibration due to atom bombardment

What is true motility?

When an organism swims and shows directional movement

What is aseptic technique?

When anything used with the culture is sterilized before and after contact.

Why is aseptic technique used?

To prevents contamination to yourself, your surroundings, and others

How is an inoculating loop sterilized?

It is held at the tip of the flame of a Bunsen burner until it is glowing hot and is moved from the intersection with the handle to the loop at the end. It is cooled before use.

Where should the cap be when using aseptic technique?

It should be held in the pinky and palm of the hand holding the instrument (opposite of the container it came from)

What are the aseptic technique steps?

1. sterilize

2. cool

3. open container with cap in pinky

4. insert instrument without touching sides

5. close container with cap and set down

6. pick up other container and open with pinky

7. insert instrument and release sample

8. tap sides to get rid of extra culture

9. remove instrument and close cap and set down

10. sterilize and cool

Why should you wait to cool the inoculating loop?

If it's too hot, it can burn away organisms that are needed, and can aerosolize bacteria that may be toxic to inhale.

Why is one end of a pipette stuffed with cotton?

To filter incoming air and prevent liquid from being drawn up over the pipette.

Which pipette aid is used for 1mL pipettes?

The blue one

Which pipette aid is used for 5-10mL pipettes?

The green one

How do you sterilize a pipette?

You don't, its already packaged as sterile so don't touch it. It will also melt in a Bunsen burner

What is the temperature of the non-room temperature incubator?

37C

When is aseptic technique successful?

When the sample/broth is transparent.

What is a stain used for?

To make their shape and grouping more visible

What happens to the cells during staining?

They die

How do you make a sample for staining from solid medium?

You sterilize, but a loop full of tap water down, sterilize, add a small amount of solid medium, spread to dime-size that is faintly cloudy, heat-fix.

What happens if a solid medium sample for staining is too thick?

It will not stain thoroughly

How do you make a sample for staining from broth cultures?

sterilize, loop full of culture, put onto slide without smearing, heat-fix.

What does heat-fixing do?

It makes the organisms stick to the glass

What are basic dyes attracted to?

Negative compounds since it carries a positive charge

Acidic dyes?

Have negative charge and are repelled by cell surface

How do you stain a heat-fixed sample?

Cover with a basic dye, stain for 30-60 secs, rinse, dry thoroughly, see through oil immersion