Lab Exam Flashcards
Wear proper clothing
wear appropriate shoes no open-toe shoes or sandals no easily flammable garments long hair tied back clothes must reach knees (no shorts/skirts)
Know location, operational details of all laboratory emergency safety equipment, disposal procedures, and evacuation routes.
eye wash in the front and at every sink
shower in the front
dispose of glass in ceramic jar, biohazards in red box, trash in trash
Eating, drinking, or use of tobacco products is strictly prohibited in science labs.
Food & drinks in backpacks
Do not work in the laboratory without the permission of and presence of responsible staff.
Do not work in the laboratory without the permission of and presence of responsible staff.
Perform only assigned laboratory activities, behave in a professional manner
careless/reckless behavior increases safety risks for everyone
Use proper techniques in handling lab materials and equipment
If you are unsure, ask for instructor’s help.
Stay out of the stockroom and preparation areas of the laboratory
Areas are off limits to students
Know what to do in an emergency
a. report all accidents immediately. All personal injuries – regardless of how trivial they may seem at the time, must be reported to the instructor and or professional laboratory personnel. College is required by law to file accident reports.
b. Know the procedure to be followed in case of personal injury:
- report it immediately
- in cases of severe injury, notify campus police (3111) and/or dial 911
c. Know what sorts of accidents are most likely to occur in the lab, as well as what action to take if an accident occurs.
Wash all glassware, dissecting supplies, etc,. that you use when you are finished with your lab exercise.
Wash all glassware, dissecting supplies, etc,. that you use when you are finished with your lab exercise.
Clean your lab table and turn off all hot plates, propane burners, and water faucets. Many students use the lab. No one but you should have to clean up your mess.
Clean your lab table and turn off all hot plates, propane burners, and water faucets. Many students use the lab. No one but you should have to clean up your mess.
Never use flammable liquids such as alcohols, gasoline, or ether near a flame.
Read the label carefully before taking any substance from a bottle. Be sure you are using the correct chemical.
Only take the amount of chemical necessary to conduct the experiment. Using larger quantities won’t make the experiment work any better. Never return unused chemicals to the reagent bottles.
Only take the amount of chemical necessary to conduct the experiment. Using larger quantities won’t make the experiment work any better. Never return unused chemicals to the reagent bottles.
Never throw solid materials (i.e., litmus papers, pH papers, lens paper, toothpicks, animal parts, etc) into the sinks. Dispose of these materials in the appropriate receptacles. Some liquid wastes may be dumped into the lab sinks (check w/ instructor); flush drain with plenty of running water.
Never throw solid materials (i.e., litmus papers, pH papers, lens paper, toothpicks, animal parts, etc) into the sinks. Dispose of these materials in the appropriate receptacles. Some liquid wastes may be dumped into the lab sinks (check w/ instructor); flush drain with plenty of running water.
If you have used a microscope during the lab period, clean all microscope lenses with lens paper when you are finished, clean off the microscope stage, shut off the light. Return to its proper shelf.
If you have used a microscope during the lab period, clean all microscope lenses with lens paper when you are finished, clean off the microscope stage, shut off the light. Return to its proper shelf.
If you have used prepared microscope slides during the lab period, clean off any immersion oil from the slides, return them to their proper box or tray (check the label).
If you have used prepared microscope slides during the lab period, clean off any immersion oil from the slides, return them to their proper box or tray (check the label).
If you are working with live microorgs and spill them on:
a. work surface or floor:
b. skin:
c: clothes
a. work surface or floor: cover w/ paper towel, flood with disinfectant; wait 15 minutes, clean up.
b. Skin: wash area thoroughly with soap and water.
c. Clothes: change clothes; wash and disinfect clothes.
When dealing with bodily fluids (saliva, urine, blood), only work with your own, or wear disposable surgical gloves and avoid skin contact.
When dealing with bodily fluids (saliva, urine, blood), only work with your own, or wear disposable surgical gloves and avoid skin contact.
Disinfect all work surfaces after working with body fluids or microorganisms. Spray & wipe down tables after every lab.
Disinfect all work surfaces after working with body fluids or microorganisms. Spray & wipe down tables after every lab.
Discard all items contaminated with body fluids or microorganisms in designated biohazard containers.
Discard all items contaminated with body fluids or microorganisms in designated biohazard containers.
Wash your hands with soap and water before leaving the lab.
Wash your hands with soap and water before leaving the lab.
FRAMEWORK
arm
base
Stage
stage – supports slide
stage adjustment – clamping devise
stage adjustment knob – for holding and moving the slide around on the stage
Light source
light intensity control – vary intensity of light, under on/off switch
neutral density filter – sometimes added over the light source in the base, or sometime built into the base
Lens system
ocular objectives nosepiece 4x 10x 40x 100x condenser diaphragm
ocular – eyepiece at the top, has 10x magnification
objectives – (lenses), attached to nosepiece
nosepiece – rotatable, moves objectives around
4x – lowest power, actually 40x (10x * 4x)
10x – “low-power”, actually 100x
40x – “high-dry”, actually 400x
100x – “oil immersion”, actually 1000x
condenser – under stage, collects and directs the light from the lamp to the slide being studied, does not affect magnifying power – moves up and down
Diaphragm – regulates amount light that reaches the slide – moves counter/clockwise
Focusing knobs
Coarse adjustment knob
Fine adjustment knob
Ocular adjustment
make adjustments on right eye first, then make changes to right eye by turning the diopter adjustment ring
Oil immersion
- Rotate oil immersion lens halfway, drop immersion oil, then rotate lens.
- Open diaphragm as high as possible, and keep condenser at highest point.
- Clean after with lens tissue
Describe position of hands when carrying microscope to and from your laboratory bench.
Use both hands, one hand on arm, one hand on base.
What two adjustments can be made to the condenser? What effect do these adjustments have on the image?
Moves up and down –collects and directs the light from the lamp to the slide being studied
Why are condenser adjustments generally preferred over the use of the light intensity control?
Differentiate limit of resolution of typical light microscope vs unaided eye
increases illumination without affecting bulb light
.2mm vs .2um
When using the oil immersion lens, what four procedures can be implemented to achieve the maximum resolution?
- oil immersion oil for continuous lens system
- blue filter for shorter wavelengths
- condenser @ highest position
- diaphragm open
Why is it advisable to start first with low-power lens when viewing a slide?
Enables you to explore the slide to look for the object you are planning to study
larger working distance prevents you from hitting and breaking the slide.
This objective lens provides the highest magnification.
oil immersion
This objective lens provides the second highest magnification.
high-dry
This objective lens provides the lowest magnification.
low-power
This objective lens has the shortest working distance.
100x – oil immersion lens
The coarse focus knob should be adjusted only when using this objective lens.
low power or rapid scanning
This lens collects and focuses light from the lamp onto the specimen on the slide.
condenser
This lens, also known as the eyepiece, often comes in pairs.
ocular
Diopter adjustments can be made to this lens.
On the ocular, with the diopter adjustment ring
A diaphragm is used to regulate light passing through this lens.
condenser
Acetone is the safest solvent for cleaning an objective lens.
False—the best is green soap with warm water or xylene.
Only lint-free, optically safe tissue should be used to wipe off microscope lenses.
True
The total magnification capability of a light microscope is only limited by the magnifying power of the lens system.
False—ocular lenses provide 10x
The coarse focus knob can be used to adjust the focus when using any of the objective lenses.
False—should only be used for lowest power
Once focus is achieved at one magnification, a higher-power objective lens can be rotated into position without fear of striking the slide.
True
The resolving power of a microscope is a function of:
a. The magnifying power of the lenses
b. The numerical aperture of the lenses
c. The wavelength of the light
d. Both a & b are correct
e. Both b & c are correct
e
The coarse and fine focus knobs adjust the distance between
a. The objective and ocular lenses
b. The ocular lenses
c. The ocular lenses and your eyes
d. The stage and the condenser lens
e. The stage and the objective lens
e
A microscope that maintains focus when the objective magnification is increased is called
a. Binocular
b. Myopic
c. Parfocal
d. Refractive
e. Resolute
c
The total magnification achieved when using a 100x oil immersion lens with 10x binocular eyepieces to
a. 10x
b. 100x
c. 200x
d. 1000x
e. 2000x
d
The most useful adjustment for increasing image contrast in low-power magnification is
a. Closing down the diaphragm
b. Closing one eye
c. Opening up the diaphragm
d. Placing a drop of oil on the slide
e. Using a blue filter
a
Before the oil immersion lens is rotated into place, you should:
a. Center the object of interest in the preceding lens
b. Lower the stage with use of the coarse focus adjustment knob
c. Place a drop of oil on the slide
d. Both A and C are correct
e. All are correct
d
Aseptic Technique
PROCEDURE: Removing organisms from a broth culture with inoculating loop
- Inoculating loop is heated until it is red-hot.
- Organisms in culture are dispersed by shaking tube.
- Tube enclosure is removed and mouth of tube is flamed.
- Loopful of organisms is removed from tube.
- Loop is removed from culture and tube mouth is flamed.
- Tube enclosure is returned to tube.
Aseptic Technique
Procedure for inoculating a nutrient broth
- Cap removed from sterile broth and tube mouth is flamed.
- Unheated loop is inserted into tube of sterile broth.
- Loop is removed from broth and tube mouth is flamed.
- Tube enclosure is returned to tube.
- Loop is flamed and returned to receptacle.
Aseptic Technique
Procedure for inoculating a nutrient agar slant from a slant culture
- Inoculating loop is heated until it is red-hot.
- Cap is removed from slant culture and tube moth is heated.
- Organism is picked up from slant with inoculating loop.
- Mouth of tube is flamed. Inoculating loop is not flamed.
- Slant culture recapped and returned to test-tube rack.
- Tube of sterile agar slant is uncapped and moth is flamed.
- Slant surface is streaked with unflamed loop in serpentine manner.
- Tube mouth is flamed, recapped, and incubated.
- Loop is flamed red-hot and returned to receptacle.
Aseptic Technique
Procedure for inoculating a nutrient agar slant from an agar plate
- Inoculating loop is heated until it is red-hot.
- With free hand, raise the lid of petri plate just enough to access a colony to pick up a loopful of organisms.
- After flaming the mouth of a sterile slant, streak its surface.
- Flame the mouth of the tube and recap the tube.
- Flame the inoculating loop and return it to receptacle.
Aseptic Technique
Provide 3 reasons why the use of aseptic technique is essential when handling microbial cultures in the lab.
- Ensures no contaminating organisms are introduced into culture materials when inoculated or handled in some manner.
- Ensures that organisms that are being handled do not contaminate the handler or others who may be present
- Ensures that no contamination remains after you have worked with cultures
Aseptic Technique
Provide two examples of how the Bunsen burner is used during inoculation of a tube culture.
- To sterilize inoculating loop (incinerates any contaminating organisms that may be present)
- To flame the tube
Aseptic Technique
How is air contamination prevented when an inoculating loop is used to introduce or take a bacterial sample to/from an agar plate?
Plate cover is raised and held diagonally over the plate to protect the surface from any contamination in the air.
Aseptic Technique
Where should a label be written on an agar plate?
On the bottom, on the side with the microorganism.
Aseptic Technique
How should agar plates be incubated? Why?
Upside down to prevent moisture from condensing on the agar surface and spreading the inoculated organisms
Aseptic Technique
Disinfectant is used on your work surface:
a. Before the beginning of laboratory procedures
b. After all work is complete
c. After any spill of life microorganism
d. Both B and C are correct
e. All of the above are correct.
E
Aseptic Technique
To retrieve a sample from a culture tube with an inoculating loop, the cap of the tube is:
a. Removed and held in one’s teeth
b. Removed and held with the fingers of the loop hand
c. Removed with the fingers of the loop hand and placed in the fingers of the tube hand
d. Removed with the fingers of the loop hand and placed on the laboratory bench
e. Any of these methods can be used
B
Aseptic Technique
An inoculating loop or needle is sterilized in a flame
a. By one brief passage
b. For exactly 5 minutes
c. Until the entire wire is bright red
d. Until the handle is bright red
e. Until the tip is bright red
C
Method A
Pure culture techniques
- Streak one loopful over area 1 near edge of plate. Apply tightly. Don’t gouge into medium.
- Flame the loop, cool 5 seconds, make 5-6 streaks from Area 1 through Area 2. Momentary touching the loop to a sterile area of the medium before streaking ensures a cool loop.
- Flame the loop again, cool, and make 6-7 streaks from Area 2 through Area 3.
- Flame the loop again, and make as many streaks as possible from Area 3 through Area 4, using up the remainder of the plate surface.
- Flame the loop before putting it aside.
Define colony
identical progeny of the original cell
What colony characteristics can be used for differentiation of bacterial species?
Color, shape, other colony characteristics
