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Microbiology Lab Exam #1 Study Guide Questions
and Answers 100% Pass
The total magnification of the oil immersion objective is: - ✔✔1000
Ocular/Eyepiece - ✔✔Binocular microscopes have two. They magnify the image tenfold.
Body - ✔✔It contains mirrors that bend the light into the ocular.
Nosepiece - ✔✔Where the objectives are attached to.
Objectives - ✔✔Contains lenses that magnify the image. A microscope has 4x, 10x, 40x and 100x
Arm - ✔✔It supports the nosepiece, holds on/off toggle and focus adjustment knobs.
Stage/Mechanical stage - ✔✔The black, flat platform on which your slide rests. Its the silver apparatus
that actually holds the slide and moves the slide to position it on the stage.
Stage Adjustment knobs - ✔✔These move the the mechanical stage
Light Intensity Control - ✔✔This knob increases or decreases light output from the light source.
Substage condenser - ✔✔It is made of at least two lenses that focus the light passing through the
specimen and improve image sharpness.
Aperture diaphragm control - ✔✔Controls the amount of light entering the substage condenser from the
light source.
Field diaphragm lever - ✔✔It opens and closes to increase and decrease light from the light source. It
should remain open
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Light source - ✔✔The illuminator is a halogen bulb that produces light.
Base - ✔✔It holds the illuminator and supports the rest of the microscope.
Fine focus adjustment knob - ✔✔Brings the image into sharp focus. This knob raises and lowers the stage
in very small increments.
Coarse focus adjustment knob - ✔✔Moves the stage up and down by larger increments and allows you to
bring the image into focus.
Resolution - ✔✔The ability of a lens system to distinguish as separate entities objects that are very small
and very close together. It is determined by the quality of the lens and the wavelength of light used.
Magnification - ✔✔Make a small object appear larger.
Working distance - ✔✔The distance between the tip of the objective and the stage
What is the purpose of oil immersion - ✔✔to minimize light scattering. It allows for a clearer, sharper
image and had better contrast
Aseptic technique - ✔✔The method of handling microbes and materials in a way that minimizes
contamination
Inoculation - ✔✔The transfer of a microbe from medium to the next
Inoculum - ✔✔The sample being transferred
Steps of aseptic technique - ✔✔Place the back of the loop wire, where it meets the handle, just above the
inner blue cone. Hold the wire in place until it becomes red hot the entire time. (do not place the loop or
needle on the bench top) Allow the loop or needle to cool slightly before putting it into a culture. (do not
wave the loop around to cool or blow on it) transfer the organisms. when transfer is finished, flame loop
again to incinerate any bacteria remaining. Then store in test tube rack or storage area
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
Microbiology Lab Exam #1 Study Guide Questions
and Answers 100% Pass
The total magnification of the oil immersion objective is: - ✔✔1000
Ocular/Eyepiece - ✔✔Binocular microscopes have two. They magnify the image tenfold.
Body - ✔✔It contains mirrors that bend the light into the ocular.
Nosepiece - ✔✔Where the objectives are attached to.
Objectives - ✔✔Contains lenses that magnify the image. A microscope has 4x, 10x, 40x and 100x
Arm - ✔✔It supports the nosepiece, holds on/off toggle and focus adjustment knobs.
Stage/Mechanical stage - ✔✔The black, flat platform on which your slide rests. Its the silver apparatus
that actually holds the slide and moves the slide to position it on the stage.
Stage Adjustment knobs - ✔✔These move the the mechanical stage
Light Intensity Control - ✔✔This knob increases or decreases light output from the light source.
Substage condenser - ✔✔It is made of at least two lenses that focus the light passing through the
specimen and improve image sharpness.
Aperture diaphragm control - ✔✔Controls the amount of light entering the substage condenser from the
light source.
Field diaphragm lever - ✔✔It opens and closes to increase and decrease light from the light source. It
should remain open
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
, 2|Page
Light source - ✔✔The illuminator is a halogen bulb that produces light.
Base - ✔✔It holds the illuminator and supports the rest of the microscope.
Fine focus adjustment knob - ✔✔Brings the image into sharp focus. This knob raises and lowers the stage
in very small increments.
Coarse focus adjustment knob - ✔✔Moves the stage up and down by larger increments and allows you to
bring the image into focus.
Resolution - ✔✔The ability of a lens system to distinguish as separate entities objects that are very small
and very close together. It is determined by the quality of the lens and the wavelength of light used.
Magnification - ✔✔Make a small object appear larger.
Working distance - ✔✔The distance between the tip of the objective and the stage
What is the purpose of oil immersion - ✔✔to minimize light scattering. It allows for a clearer, sharper
image and had better contrast
Aseptic technique - ✔✔The method of handling microbes and materials in a way that minimizes
contamination
Inoculation - ✔✔The transfer of a microbe from medium to the next
Inoculum - ✔✔The sample being transferred
Steps of aseptic technique - ✔✔Place the back of the loop wire, where it meets the handle, just above the
inner blue cone. Hold the wire in place until it becomes red hot the entire time. (do not place the loop or
needle on the bench top) Allow the loop or needle to cool slightly before putting it into a culture. (do not
wave the loop around to cool or blow on it) transfer the organisms. when transfer is finished, flame loop
again to incinerate any bacteria remaining. Then store in test tube rack or storage area
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
