Microbiology Lab Exam #2 Study
Guide/ 85 Questions and Answers/
Verified.
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
-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
-When using a test tube, you first remove the cap using the ________ - -last two
fingers
-T/F After opening the test tube you flame it - -True
-T/F When removing an inoculum from a plate you remove the lid and place it on the
lab bench - -False
-Identify a colony margin by name - -Entire, Undulate, Lobate, Filamentous and Curled
Guide/ 85 Questions and Answers/
Verified.
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
-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
-When using a test tube, you first remove the cap using the ________ - -last two
fingers
-T/F After opening the test tube you flame it - -True
-T/F When removing an inoculum from a plate you remove the lid and place it on the
lab bench - -False
-Identify a colony margin by name - -Entire, Undulate, Lobate, Filamentous and Curled
