Portage learning Module 3 EXAM NEWEST 2024 COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS (VERIFIED ANSWERS)
Micrometer (um) - Answer -- a millionth of a meter
- 10-6m
Nanometer (nm) - Answer -10^-9 m or one-billionth of a meter
How many meter can unaided eye can resolve(see clearly)? - ...
Portage learning Module 3 EXAM NEWEST
2024 COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
Micrometer (um) - Answer -- a millionth of a meter
- 10-6m
Nanometer (nm) - Answer -10^-9 m or one-billionth of a meter
How many meter can unaided eye can resolve(see clearly)? - Answer ->100um
how small can the cellular components, organelles can be? - Answer -as small as
0.2um in diameter.
2 critical factors that influence our ability to see an object: - Answer -resolution &
contrast
Resolution - Answer -the distance between 2 objects at which the object still can b seen
as separate.
- the closer 2 objects are to each other, the greater the resolution requirement will be to
maintain viewing the 2 objects as separate.
Contrast - Answer -the difference in light absorbable between 2 areas(objects)
- lower the contrast between an object and its background, the harder it will be to see
that object.
- the greater the contrast between 2 areas the easier it will be visualize.
Bright Field Microscope - Answer -- the simplest form of light, or optical, microscopes.
How does the light travel when using microscope? - Answer -- light emitted from a
standard halogen bulb, condenser, iris diaphragm, objective, ocular lens(eyepiece) to
the eye. (the light enters the microscope from the base(bottom) & is reflected via mirrors
towards the sample.)
Condenser - Answer -it's where the light pass before light reaches the sample.
- it converge the light beams into a focused area on the sample.
Iris diaphragm - Answer -controls the amount of light that passes through the sample
and into the objective lens.
Objective lens - Answer -The lens closest to the sample and yields the greatest amount
of magnification.
, The degree of magnification is directly proportional to what? - Answer -to the amount of
light needed.
- to image samples clearly at higher magnifications, more light is required.
ocular lens (eyepiece) - Answer -remagnifies the image formed by the objective lens
What contributes the total magnification? - Answer -objective X ocular.
- typical power of an ocular lens is 10x
Why stain the sample? - Answer -It's required due to the limitation of resolution on
unstained cells because the flat and transparent regions of a cell may appear invisible
under bright field conditions.
What are the 2 methods to stain the samples? - Answer -- heat or chemical method
before adding the dye
Phase Contrast Microscope - Answer -It have a distinct advantage over bright field
microscopy because it's able to provide detailed images of live cells without staining.
When to use phase contrast microscope and why? - Answer -- to visualize cell
movement(motility), without altering the cell morphology commonly brought about from
treating the cells with a fixing agent.
- It amplifies the slight differences between cells and the surrounding
medium(background) to make the cells highly distinguishable.
Dark Field Microscope - Answer -Used to increase the contrast between a specimen &
background, resulting in a dark background with bright objects in it.
How dark field microscope different from bright field or phase contrast microscopy? -
Answer -Dark field microscopy reflects light off of the specimen at an angle & the
reflective approach doesn't permit the visualization of intracellular structures.
Fluorescence Microscope - Answer -An optical microscope that uses fluorescence
molecules(fluorophores) to visualize cells in a dark background
How does fluorescence microscope work? - Answer -the incoming light is in the form of
the ultraviolet(UV) spectrum.
- the UV light excite different fluorophores at varying wavelengths, enabling scientists to
use a wide array of colors during imaging.
List the important tools in microscopy - Answer -Green, yellow & red fluorescent
proteins(GFP, YFP & RFP)
The fluorescent proteins alone can be expressed in a cell: - Answer -1. nonspecifically
illuminating the cell as a whole
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