Bios 260 Lab Exam Questions

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Bios 260 Lab Exam Questions

• Total magnification = magnification by the lens x magnification by the

lens.–Answer ocular...objective

• Read the instructions for using the microscope carefully.

is used for cleaning the condenser and objective lenses.–Answer lens paper

• When you start, the condenser should be nearly even with the stage and the iris diaphragm

should be open.–Answer True

• You should rotate the nosepiece by the objectives.

–Answer False

• Parfocal means that the . If you don't

remember this, please review what you learned about microscopes in your general biology class or research online.–Answer image should remain mostly in focus as you increase in magnification

• Before advancing to a higher objective, the specimen must be

. If you are not sure about the answer, please recall your experience using microscopes in your general biology class.

• in focus
• centered
• out of the center

–Answer a and b 1 / 3

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• If you are working with a bacterial smear, you must use the

lens in the final step.–Answer oil immersion

• It is extremely important to work through the 10X, then 40X objectives, adjusting the fine

focus and lighting for each before advancing to oil immer- sion.–Answer True

• The scan, 10X and 40X lenses and other parts of the microscope should not get any oil on

them.–Answer True... this is very important

• The stage should be moved down to add oil to the slide.

–Answer False

• To remove the oil from the lenses, should be used.

–Answer Lens paper

• If you see rods under the microscope, the morphology is

–Answer bacillus

• The name of the dye used in the negative stain is and it is

.–Answer nigrosin, acidic

• Bacteria have a surface.

–Answer negative charged

• The negative staining technique is used to You

Answered 2 / 3

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• determine morphology and cellular arrangement that are too delicate to withstand

heat-fixing

• determine the accurate size since there is minimal cell shrinkage
• identify acid-fast organisms

differentiate gram-negative organisms –Answer A and B

• If you look in the microscope and see chains of organisms, the prefix is termed .

–Answer strepto

• If you look in the microscope and see clusters of organisms, the prefix is termed .

–Answer Staphylo

• The dye we will use for the negative stain is called , and it will

stain the .–Answer nigrosin, background

• If you see spheres under the microscope, the morphology of the bacteria is

–Answer coccus

• If you see curved shaped organisms under the microscope, the morphol- ogy of the

bacteria is –Answer spirals/spirillium

• Purple organisms observed on a Gram stain are

–Answer Gram-positive

• Red organisms observed on a Gram stain are

–Answer Gram-negative

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