Chapter 3 Flashcards
units to measure microorganisms
nanometer
micrometer
A simple microscope has only ___ lens.
Similar to a magnifying glass, but whit a much better (higher magnification) lens
1
Light microscopy
Any kind of microscope that uses visible light to observe specimens
Including:
Compound light microscopy
Darkfield microscopy
Phase-contrast microscopy
Differential interference contrast microscopy
Fluorescence microscopy
Confocal microscopy
Compound light microscope
Magnify the image from the objective lens again by the ocular lens
Formula of total magnification
Total objectives x Total ocular
Resolution
the ability of the lenses to distinguish two points
a microscope with a resolving power of 0.4 nm can distinguish between two points at least ___ nm apart
4
Better solution = ____ wavelength
shorter
the visible light with the shortest wavelength is
390nm
For microscopes using visible light, the limitation for the smallest subjects is ___ __, because 390 nm lights cannot interact with subjects < ___ __
200nm x2
To see things smaller than 200 nm, you need smaller ________ particles, such as ______ in electron microscopes
wavelength
electrons
The ________ _____ is a measure of the light-bending ability of a medium (for example, the sample is a medium).
Light may refract after passing through a specimen to an extent that it does not pass through the _______ ____.
________ ___ is used to reduce light refraction. It is required for high magnification objective lens (100x)
refractive index
objective lens
immersion oil
Why do 100x objective lens need immersion oil?
High magnification lens are usually SMALLER in sizes/diameter in order to increase resolution.
Smaller lens collect fewer lights.
Therefore, you need immersion oil to REDUCE LIGHT REFRACTION in order to collect enough light.
How will a sample look if you forget to use immersion oil with the 100x lens?
Blurry or darker
Compound (Brightfield) Light Microscope:
-____ ______ are visible against a bright background
-light reflected off the specimen does not enter the ________ ____
-___ _______ in unstained specimens
dark objects
objective lens
low contrast
Darkfield Microscopy:
-_____ _______ are visible against a dark background
-_______ ____ placed in condenser
- only light reflected ___ ___ ______ enters the objective lens
light objects
opaque disk
off the specimen
Phase-Contrast Microscopy:
-allows examination of ______ ______ and ______ ____ ________ without ______
- Use _______ ________ and _________ ____ to bring together two sets of lights rays, direct rays, and diffracted rays to form an image with better ______
living organisms
internal cell structures
staining annular diaphragm
diffraction plate
contrast
Differential Interference Contrast (DIC) Microscopy:
- similar to phase-contrast that can reveal some ______ ______ without ______
- uses ___ _____ _____ and ______ to split light beams, giving more ______ and _____ to the specimen
internal structures
staining
two light beams
prisms
contrast
color
Fluorescence Microscopy:
-Uses _____ ________ light with ______ _____ (ex. UV/violet/blue)
-Fluorescent substances absorb higher energy light and emit _____ ________ (like red/yellow/green) light with lower energy
-In most cases, cells need to be stained with fluorescent dyes (___________)
-Fluorescence-antibody technique (immunofluorescence): use ________ conjugated with fluorochromes to detect _______ (proteins or polysaccharides) of cells
-samples can be ____ cells or _____ cells (dead cells)
short wavelength; higher energy
longer wavelength
fluorochromes
antibodies; antigen
live; fixed
Fluorescence labeling allows us to detect presence/localization/quantity of ___________ (proteins or polysaccharides) withing a cell or on the surface of a cell
macromolecules
Fluorescent treponemal antibody absorption (FTA-ABS) test using fluorescence microscopy:
Cells may be stained with fluorescent dyes (___________) or _______ conjugated with fluorochromes
fluorochromes; antibodies
Confocal Microscopy:
- Cells are stained with ________ dyes or ________ conjugated with fluorochrome
-_____-_______ (ex. blue) light generate by a laser is used to excite a single ____ of a specimen
- Each plane in a specimen is illuminated and a _____-_______ image is constructed with a computer
-reduce _____ noise; better ______
fluorochrome; anitbodies
short-wavelength; plane
three-dimensional
light; contrast
