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Microbiology Lab Exam #1 Study Guide
Questions And Answers 100% Pass.
The total magnification of the oil immersion objective is: - Answer✔1000
Ocular/Eyepiece - Answer✔Binocular microscopes have two. They magnify the image tenfold.
Body - Answer✔It contains mirrors that bend the light into the ocular.
Nosepiece - Answer✔Where the objectives are attached to.
Objectives - Answer✔Contains lenses that magnify the image. A microscope has 4x, 10x, 40x
and 100x
Arm - Answer✔It supports the nosepiece, holds on/off toggle and focus adjustment knobs.
Stage/Mechanical stage - Answer✔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 - Answer✔These move the the mechanical stage
Light Intensity Control - Answer✔This knob increases or decreases light output from the light
source.
Substage condenser - Answer✔It is made of at least two lenses that focus the light passing
through the specimen and improve image sharpness.
Aperture diaphragm control - Answer✔Controls the amount of light entering the substage
condenser from the light source.
Field diaphragm lever - Answer✔It opens and closes to increase and decrease light from the light
source. It should remain open
Light source - Answer✔The illuminator is a halogen bulb that produces light.
Base - Answer✔It holds the illuminator and supports the rest of the microscope.
Fine focus adjustment knob - Answer✔Brings the image into sharp focus. This knob raises and
lowers the stage in very small increments.
Coarse focus adjustment knob - Answer✔Moves the stage up and down by larger increments and
allows you to bring the image into focus.
, © EVERLY 2025 ALL RIGHTS RESERVED.
Resolution - Answer✔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 - Answer✔Make a small object appear larger.
Working distance - Answer✔The distance between the tip of the objective and the stage
What is the purpose of oil immersion - Answer✔to minimize light scattering. It allows for a
clearer, sharper image and had better contrast
Aseptic technique - Answer✔The method of handling microbes and materials in a way that
minimizes contamination
Inoculation - Answer✔The transfer of a microbe from medium to the next
Inoculum - Answer✔The sample being transferred
Steps of aseptic technique - Answer✔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
When using a test tube, you first remove the cap using the ________ - Answer✔last two fingers
T/F After opening the test tube you flame it - Answer✔True
T/F When removing an inoculum from a plate you remove the lid and place it on the lab bench -
Answer✔False
Identify a colony margin by name - Answer✔Entire, Undulate, Lobate, Filamentous and Curled
T/F When inoculating a broth, the loop may not touch the sides of the tube - Answer✔True
Ciguatera toxin is a naturally occurring toxin produced by the dinoflagellate: -
Answer✔Gambierdiscus toxicus
Cyanobacteria is classified as - Answer✔in the past plants, protozoans and bacteria but now as
bacteria
Cyanobacteria derived their energy from - Answer✔oxygen-evolving photosynthesis
Cyanobacteria utilize - Answer✔chlorophyll - the same pigment used by higher plants, to
capture light energy
Cyanobacteria contain - Answer✔accessory pigments called phycobilins
Heterocysts (thick walled cells) are responsible for ______ whereas akinetes are: -
Answer✔nitrogen fixation; reproductive structures, large usually about two to three times large
Microbiology Lab Exam #1 Study Guide
Questions And Answers 100% Pass.
The total magnification of the oil immersion objective is: - Answer✔1000
Ocular/Eyepiece - Answer✔Binocular microscopes have two. They magnify the image tenfold.
Body - Answer✔It contains mirrors that bend the light into the ocular.
Nosepiece - Answer✔Where the objectives are attached to.
Objectives - Answer✔Contains lenses that magnify the image. A microscope has 4x, 10x, 40x
and 100x
Arm - Answer✔It supports the nosepiece, holds on/off toggle and focus adjustment knobs.
Stage/Mechanical stage - Answer✔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 - Answer✔These move the the mechanical stage
Light Intensity Control - Answer✔This knob increases or decreases light output from the light
source.
Substage condenser - Answer✔It is made of at least two lenses that focus the light passing
through the specimen and improve image sharpness.
Aperture diaphragm control - Answer✔Controls the amount of light entering the substage
condenser from the light source.
Field diaphragm lever - Answer✔It opens and closes to increase and decrease light from the light
source. It should remain open
Light source - Answer✔The illuminator is a halogen bulb that produces light.
Base - Answer✔It holds the illuminator and supports the rest of the microscope.
Fine focus adjustment knob - Answer✔Brings the image into sharp focus. This knob raises and
lowers the stage in very small increments.
Coarse focus adjustment knob - Answer✔Moves the stage up and down by larger increments and
allows you to bring the image into focus.
, © EVERLY 2025 ALL RIGHTS RESERVED.
Resolution - Answer✔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 - Answer✔Make a small object appear larger.
Working distance - Answer✔The distance between the tip of the objective and the stage
What is the purpose of oil immersion - Answer✔to minimize light scattering. It allows for a
clearer, sharper image and had better contrast
Aseptic technique - Answer✔The method of handling microbes and materials in a way that
minimizes contamination
Inoculation - Answer✔The transfer of a microbe from medium to the next
Inoculum - Answer✔The sample being transferred
Steps of aseptic technique - Answer✔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
When using a test tube, you first remove the cap using the ________ - Answer✔last two fingers
T/F After opening the test tube you flame it - Answer✔True
T/F When removing an inoculum from a plate you remove the lid and place it on the lab bench -
Answer✔False
Identify a colony margin by name - Answer✔Entire, Undulate, Lobate, Filamentous and Curled
T/F When inoculating a broth, the loop may not touch the sides of the tube - Answer✔True
Ciguatera toxin is a naturally occurring toxin produced by the dinoflagellate: -
Answer✔Gambierdiscus toxicus
Cyanobacteria is classified as - Answer✔in the past plants, protozoans and bacteria but now as
bacteria
Cyanobacteria derived their energy from - Answer✔oxygen-evolving photosynthesis
Cyanobacteria utilize - Answer✔chlorophyll - the same pigment used by higher plants, to
capture light energy
Cyanobacteria contain - Answer✔accessory pigments called phycobilins
Heterocysts (thick walled cells) are responsible for ______ whereas akinetes are: -
Answer✔nitrogen fixation; reproductive structures, large usually about two to three times large
