Portage Microbiology Exam 3 Questions and Answers
Already Passed
micrometer - ANSWER one millionth of a meter, 10^ -6
nanometer - ANSWER one billionth of a meter, 10^-9
Resolution - ANSWER The distance at which two objects are still seen as seperate
What happens if the resolution is poor? - ANSWER Poor or low resolution means
two (or more) objects may appear as one!
Contrast - ANSWER the difference in light absorbance between two objects
What happens if there is poor contrast? - ANSWER The lower the contrast
between an object and its background, the harder it will be to see that object
If you wish to increase the amount of light going into a microscope, what part would
you adjust? - ANSWER The iris diaphragm
As light passes through a microscope, what is the last piece that light passes before
reaching your eyes? - ANSWER the ocular lens, or eyepiece, directly into your
eye.
How is the total magnification of an object calculated? - ANSWER Total
magnification is calculated by multiplying the power of the objective and the power of
the eyepiece.
What is one limitation of fixing your sample? - ANSWER It kills the sample so
viewing motility (cell movement) is impossible.
It also can distort the specimen's shape and arrangement.
Phase-contrast microscopy provided what benefits to imaging? - ANSWER It can
provide detailed images of live cells without staining
Able to visualize certain structures that would otherwise be invisible
What is the distinguishing feature of dark field microscopy? - ANSWER it reflects
light off of the specimen at an angle
The resulting image is an exceptionally dark background and a vibrant specimen.
Unlike brightfield microscope, fluorescence microscopes illuminate samples through
what spectrum? - ANSWER It illuminates samples through the UV Spectrum.
Already Passed
micrometer - ANSWER one millionth of a meter, 10^ -6
nanometer - ANSWER one billionth of a meter, 10^-9
Resolution - ANSWER The distance at which two objects are still seen as seperate
What happens if the resolution is poor? - ANSWER Poor or low resolution means
two (or more) objects may appear as one!
Contrast - ANSWER the difference in light absorbance between two objects
What happens if there is poor contrast? - ANSWER The lower the contrast
between an object and its background, the harder it will be to see that object
If you wish to increase the amount of light going into a microscope, what part would
you adjust? - ANSWER The iris diaphragm
As light passes through a microscope, what is the last piece that light passes before
reaching your eyes? - ANSWER the ocular lens, or eyepiece, directly into your
eye.
How is the total magnification of an object calculated? - ANSWER Total
magnification is calculated by multiplying the power of the objective and the power of
the eyepiece.
What is one limitation of fixing your sample? - ANSWER It kills the sample so
viewing motility (cell movement) is impossible.
It also can distort the specimen's shape and arrangement.
Phase-contrast microscopy provided what benefits to imaging? - ANSWER It can
provide detailed images of live cells without staining
Able to visualize certain structures that would otherwise be invisible
What is the distinguishing feature of dark field microscopy? - ANSWER it reflects
light off of the specimen at an angle
The resulting image is an exceptionally dark background and a vibrant specimen.
Unlike brightfield microscope, fluorescence microscopes illuminate samples through
what spectrum? - ANSWER It illuminates samples through the UV Spectrum.
