cm4 microscopy
DESCRIPTION
by : Ms. Crizelda LiwanagTRANSCRIPT
microscopy
One of the most widely used tools in biological sciences
An instrument that produces an enlarged image of an object
Magnification – the increase in an object’s apparent size
Resolution – the power of a microscope to clearly show detail
Principle:
The microscope objective first forms in
the tube a magnified aerial image of the
specimen illuminated below the lamp
and the condenser. The image is then
viewed magnified through the eyepiece.
microscope
What is the standard length of the draw tube?
160 mmWhich is the most important component of the microscope?
Objective lenses If the image remains visible after the exchange of objectives, the lenses are
said to be_____parfocal
I. Light microscopes
1. Simple
2. Compound
a. Brightfield
b. Darkfield
c. Phase contrast
d. Ultraviolet
e. Fluorescence
f. Stereoscopic
II. Electron microscopes
1. transmission
2. scanning
Type of
microscopy
appearancemagnification
use
Brightfield Microbe
stained
1000x Overall
appearance of
most microbes
Dark field Light
microbe not
stained
1000x Overall
appearance of
most microbes
Phase
contrast
Cellular
component
s resolved
1000x Resolution of
many cellular
components
Type of
microscopy
appearancemagnification
use
Ultraviolet UV
absorbing
portion of
cell emitting
light
1000x to
3000x
Cellular
components
that absorb
light
Fluorescent Microbe
fluorescing
1000x to
3000x
m-o’s coated
w/ dye
fluoresce
when struck
by UV
Type of
microscopy
Appearancemagnification
use
TEM Ultrathin
section
showing
cellular
component
s (2-D)
Up to
200,000x
Study of
viruses and
detailed
structure of
larger m-o’s
SEM Surface of
microbe
(3-D)
Up to
50,000x
Study of
surface
structure of
m-o’s
Brightfield Microscope
Dark image
against a
bright or
white
background
Thin, flat components of low
refractile elements and living
cells
polarized light
for birefringent substances
Brightly illuminated specimen
against a dark background
Fluorescent substances
Filters: excitation & barrier
Electron beams &
magnetic lenses
