MBIO 3401 LAB EXAM 1 QUESTIONS AND ANSWERS
2026
Ubiquity - Answers - occurs everywhere
Microbes - Answers - -cause disease in plants and animals
-be used to produce antibiotics and other pharmaceuticals
-can be used to produce a wide range of food products
-can be used in industry
-important in nutrient cycling
Which plates are incubated agar side up/down? - Answers - lid up: PDA
lid down: TSA, BHI - condensation
Magnification - Answers - size of the object under the microscope
Objectives - Answers - lenses closest to the specimen on the microscope slide
Resolution - Answers - distance between two objects
Contrast - Answers - light difference between two objectives
What is the difference between a compound and dissecting scope? - Answers - -
compound: used to view much smaller objects (100-1000X)
-dissecting: used to view larger specimen; has no objectives (10-200X)
Parfocal - Answers - once the low-power objective has been focused sharply on the
specimen, the high-dry an oil immersion objectives will also be approximately in focus
after they are rotated into place
Know how to label parts of a microscope. **Page 10-11 - Answers - -condenser
diaphragm: adjusts the amount of light entering the microscope
-stage
-oculars (eyepiece)
, -revolving nosepiece
-objectives
-slide holder
-diaphragm lever
-light intensity control
-adjustment knobs
Know the magnification and name of each objective and oculars. - Answers - -low
power: 10X
-high-dry: 40X
-oil immersion: 100X
-ocular: 10X
Be able to calculate total magnification. - Answers - multiply by ocular (10X)
Tips for success. - Answers - -Carry microscope with BOTH hands(1 on arm, 1 on base)
-Clean ocular and objective lenses before and after use, don't use alcohol or organic
solvents
-Do not get oil on low-power or high-power objectives (10x and 40x respectively)
-Do not remove parts or force anything to move
-Return objective to 10x/low-power when finished
Wet mount - Answers - a *liquid suspension* of living microorganisms prepared on a
microscope slide and viewed under the light microscope
Advantages of wet mount - Answers - -no distortions from fixing procedures
-see if microbe is motile
-allows you to determine the undistorted sizes and shapes....and see arrangements
-*see in natural state*
Disadvantages of a wet mount - Answers - -dry out quickly, evaporation
-*might move out of focus*
2026
Ubiquity - Answers - occurs everywhere
Microbes - Answers - -cause disease in plants and animals
-be used to produce antibiotics and other pharmaceuticals
-can be used to produce a wide range of food products
-can be used in industry
-important in nutrient cycling
Which plates are incubated agar side up/down? - Answers - lid up: PDA
lid down: TSA, BHI - condensation
Magnification - Answers - size of the object under the microscope
Objectives - Answers - lenses closest to the specimen on the microscope slide
Resolution - Answers - distance between two objects
Contrast - Answers - light difference between two objectives
What is the difference between a compound and dissecting scope? - Answers - -
compound: used to view much smaller objects (100-1000X)
-dissecting: used to view larger specimen; has no objectives (10-200X)
Parfocal - Answers - once the low-power objective has been focused sharply on the
specimen, the high-dry an oil immersion objectives will also be approximately in focus
after they are rotated into place
Know how to label parts of a microscope. **Page 10-11 - Answers - -condenser
diaphragm: adjusts the amount of light entering the microscope
-stage
-oculars (eyepiece)
, -revolving nosepiece
-objectives
-slide holder
-diaphragm lever
-light intensity control
-adjustment knobs
Know the magnification and name of each objective and oculars. - Answers - -low
power: 10X
-high-dry: 40X
-oil immersion: 100X
-ocular: 10X
Be able to calculate total magnification. - Answers - multiply by ocular (10X)
Tips for success. - Answers - -Carry microscope with BOTH hands(1 on arm, 1 on base)
-Clean ocular and objective lenses before and after use, don't use alcohol or organic
solvents
-Do not get oil on low-power or high-power objectives (10x and 40x respectively)
-Do not remove parts or force anything to move
-Return objective to 10x/low-power when finished
Wet mount - Answers - a *liquid suspension* of living microorganisms prepared on a
microscope slide and viewed under the light microscope
Advantages of wet mount - Answers - -no distortions from fixing procedures
-see if microbe is motile
-allows you to determine the undistorted sizes and shapes....and see arrangements
-*see in natural state*
Disadvantages of a wet mount - Answers - -dry out quickly, evaporation
-*might move out of focus*
