MICROSCOPE Flashcards
1
Q
- a lab instrument used to examine objects that are too small to be seen by naked eye.
A
Microscope
2
Q
- Two types of lens to magnify the object being observed.
- Two types of lenses
o eyepiece lens: magnify 10x
o objective lens: creates resolved image then magnified by eyepiece lens for viewing - With different zoom levels of magnification
- Compound microscope with external source of light
- Compound microscope with light source
o Light microscope – 1,000
o Electron microscope – 100,000x
o Atomic force microscope - powerful equipment that magnifies almost any type of surfaces, including polymers, ceramics, composite glasses
A
Compound Microscope
2
Q
- Magnifies 1,000x
- Source of light: visible light
- Magnifying lens system
(1)eyepiece (ocular) – contains ocular lens
(2)objective lenses - positioned above the object
A
Light Microscope
2
Q
Types of Microscope
A
- Simple Microscope
- Compound Microscope
- Light Microscope
- Bright-Field Microscope
- Dark-Field Microscope
- Phase-Contrast Microscope
- Differential Interference Contrast Microscope
- Fluorescent Microscope
- Confocal Microscope
- Electron Microscope
- Scanning Probe Microscope
3
Q
- science of investigating small objects & structures using a microscope
A
Microscopy
4
Q
- Only one lens or group of lenses in one unit to magnify objects
- Examples of Simple Microscope:
Jewelry eyepieces
Pocket magnifiers
Reading glasses
A
Simple Microscope
5
Q
- Uses REFLECTED LIGHT instead of
transmitted light - Has OPAQUE DISC that blocks light
- SPECIMEN: Appears bright
- BACKGROUND: dark
- Only the OBJECT is illuminated in darkfield microscope
- Purpose:
o For spirochetes
o For external details of specimen. ex. Outline of the cell
o For unstained, transparent, absorbs little/no light
A
Dark-Field Microscope
5
Q
- Illuminates FIELD evenly
- SPECIMEN appears dark
- w/ low contrast, so object needs STAINING
- Magnify 1,000 to 1,500 times
- For bacteria & fungi
- For stained & naturally pigmented object like RBC
- Source of illumination: Visible light
- Cannot view - If object is 0.2 um or less
A
Bright-Field Microscope
6
Q
- Confocal Laser Scanning Microscope (CLSM)
- Uses COMPUTER
- Produces 3-dimensional image
- Used to study physiology of cell
- Object is stained w/ FLUORESCENT dye to emit light
- SCANNED by LASER in PLANES & REGION
A
Confocal Microscope
6
Q
- Uses:
(1) ultraviolet light
(2) fluorescent dyes: fluorochromes - The object Fluoresces or appears to SHINE against dark background
- To detect antigen & antibodies
- Example: Immunofluorescence or the Fluorescent – antibody technique
A
Fluorescent Microscope
6
Q
- Nomarski Interference contrast (NIC)
- Developed by George Nomarski, 1952
- Utilizes 2 beams of light instead of one
- Appear 3D
- Results:
higher resolution
contrasting color d/t PRISMS
A
Differential Interference Contrast Microscope
7
Q
- Introduced by Frits Zernike, Dutch physicist,1934
- Produces high-contrast images of specimen (w/ contrast enhancing optical technique)
- Purpose
o For transparent specimen: thin tissue slices, living cells in culture, & subcellular particles (Example: Nuclei & organelles)
o Detailed exam of internal structures (Example: Endospores)
o Study of binary fission & motility
A
Phase-Contrast Microscope
8
Q
original electron microscope
2-dimensional; black & white image
magnifies 200,000x
A
Transmission electron microscope (Tem)
8
Q
- Source of illumination: beam of ELECTRON & magnet to focus the beam
- Magnifies up to 2 million times
- Ernst Ruska, German Engr (1933) – Built first prototype
- Resolution power up to 50nm
- For: virus, subcellular structure of cell
A
Electron Microscope
9
Q
Types of Electron Microscope
A
o Transmission electron microscope (Tem)
o Scanning Electron Microscope (Sem)
9
Q
3-D structure; black & white
magnify 10,000 times
A
Scanning Electron Microscope (Sem)
9
Q
- Developed by Dr. Gerd Binnig & Dr. Heinrich Rohrer, Swiss Scientists, 1980
- Physical probe – goes back & forth organism
- Computer – gathers data; generate image
Produces a map showing bumps & valleys of the ATOM on the surface
A
Scanning Probe Microscope
