MICROBIOLOGY
Module 3 Exam |Portage learning
2025|Actual Exam |Well Elaborated |100%
Verified Q&A.
what does phase contrast microscopes do
➢ instead of dyes, phase contrast microscopes use special condensers and lenses to enhance tiny
differences in how light passes through the cell compared to its surroundings
-these differences are normally hard to detect but this microscope amplifies them so the cells
stand out clearly against the background
what is phase contrast microscopy good for
➢ observing live cell behaviors like swimming or gliding, without needing to kill or damage the
cells.
-this microscope helps avoid common distortion caused by fixing & staining methods
How is the phase contrast microscope capable of this
➢ A phase contrast microscope uses special parts to turn those small changes into differences in
brightness, making the details of unstained, live cells visible as light and dark areas
-when light passes through a cell, different parts slow it down slightly, but regular microscopes
can detect these tiny changes-- so the cell looks nearly invisible.
-Although phase contrast microscopy can image live cells in great detail,
➢ often scientists will still use organelle specific dyes to highlight a particular region of the cell. For
instance, although the cell membrane, nucleus, and other organelles are readily apparent, a
researcher interested in the trans-Golgi (TGN) region may still add a dye that specifically binds
within the TGN just to make it more prominent in the final acquired image.
Dark field microscopes
➢ Are used to make specimens stand out by creating a dark background with bright, glowing
objects,
-unlike brightfield or phase contrast microscopes, where light shines through the sample, dark
field microscopes shine light from the side
, - the light bounces off the edges of the specimen making it visible against the dark background.
BUT it only shows light reflected from the surface
-you can't see the details inside the cells- just outlines or shapes
Fluoresce microscopes
➢ uses special glowing molecules called flourophores to see cells on a dark background, instead of
a regular light, they use a UV light which makes these molecules light up in different colors
What are the florescent proteins used in the florescent microscopes
1. GFP (Green)
2. YFP (Yellow)
3. RFP (Red)
what do these colored proteins do?
1. light up the whole cell
2. attach to a specific protein to see where it goes inside the cell
3. Stick to a target (like with an antibody) to show whether something is there or not--
-if it glows its there if it doesn't, its not
The colored proteins overall help
➢ the scientists see whats happening inside cells in more detail, using color to highlight different
parts
confocal laser scanning microscope
➢ advanced microscopes that use lasers and work a lot like fluorescence microscopy but with
added ability to create 3D images of cells.
While regular light or floruescnece only focuses on a single flat layer (2D),
➢ Confocal microscopes can take pictures in multiple layers, one on top of the other.
instead of using halogen light or UV (fluorescent), confocal microscopes use....
➢ -laser beams to focus on one thin layer of the sample with high precision.
-After capturing one image, the laser moves up or down to the next thin layer and ties another
picture and repeats this process throughout the sample.
- then a computer puts all the 2D images together to build a 3D image of the cell.
- think of this like stacking sheets of paper- each sheet is one 2D layer, when you stack enough
of them you can imagine the full 3D shape
Module 3 Exam |Portage learning
2025|Actual Exam |Well Elaborated |100%
Verified Q&A.
what does phase contrast microscopes do
➢ instead of dyes, phase contrast microscopes use special condensers and lenses to enhance tiny
differences in how light passes through the cell compared to its surroundings
-these differences are normally hard to detect but this microscope amplifies them so the cells
stand out clearly against the background
what is phase contrast microscopy good for
➢ observing live cell behaviors like swimming or gliding, without needing to kill or damage the
cells.
-this microscope helps avoid common distortion caused by fixing & staining methods
How is the phase contrast microscope capable of this
➢ A phase contrast microscope uses special parts to turn those small changes into differences in
brightness, making the details of unstained, live cells visible as light and dark areas
-when light passes through a cell, different parts slow it down slightly, but regular microscopes
can detect these tiny changes-- so the cell looks nearly invisible.
-Although phase contrast microscopy can image live cells in great detail,
➢ often scientists will still use organelle specific dyes to highlight a particular region of the cell. For
instance, although the cell membrane, nucleus, and other organelles are readily apparent, a
researcher interested in the trans-Golgi (TGN) region may still add a dye that specifically binds
within the TGN just to make it more prominent in the final acquired image.
Dark field microscopes
➢ Are used to make specimens stand out by creating a dark background with bright, glowing
objects,
-unlike brightfield or phase contrast microscopes, where light shines through the sample, dark
field microscopes shine light from the side
, - the light bounces off the edges of the specimen making it visible against the dark background.
BUT it only shows light reflected from the surface
-you can't see the details inside the cells- just outlines or shapes
Fluoresce microscopes
➢ uses special glowing molecules called flourophores to see cells on a dark background, instead of
a regular light, they use a UV light which makes these molecules light up in different colors
What are the florescent proteins used in the florescent microscopes
1. GFP (Green)
2. YFP (Yellow)
3. RFP (Red)
what do these colored proteins do?
1. light up the whole cell
2. attach to a specific protein to see where it goes inside the cell
3. Stick to a target (like with an antibody) to show whether something is there or not--
-if it glows its there if it doesn't, its not
The colored proteins overall help
➢ the scientists see whats happening inside cells in more detail, using color to highlight different
parts
confocal laser scanning microscope
➢ advanced microscopes that use lasers and work a lot like fluorescence microscopy but with
added ability to create 3D images of cells.
While regular light or floruescnece only focuses on a single flat layer (2D),
➢ Confocal microscopes can take pictures in multiple layers, one on top of the other.
instead of using halogen light or UV (fluorescent), confocal microscopes use....
➢ -laser beams to focus on one thin layer of the sample with high precision.
-After capturing one image, the laser moves up or down to the next thin layer and ties another
picture and repeats this process throughout the sample.
- then a computer puts all the 2D images together to build a 3D image of the cell.
- think of this like stacking sheets of paper- each sheet is one 2D layer, when you stack enough
of them you can imagine the full 3D shape
