Techniques Used in Cell Biology by Naveed Ullah Marwat

1. Techniques Used in
Cell Biology
❑Microscopy
❑Staining
❑Centrifugation (cell
differentiations)
❑Tissue Culture
❑Chromatography
❑Electrophoresis
❑Microdissection

2. Microscopy
•The use of an optical
instrument that magnifies an
object to view different
organisms
or
•Microscopyis the science of
investigating small objects and
structures using microscopes.

3. What is Microscope
•An optical instrument used for
viewing very small objects, such as
mineral samples or animal or plant
cells, typically magnified several
hundred times.
Or
•It refers to anoptical instrument that
uses a lens or an arrangement of
lenses to magnify an object

4. World 1
st
Microscope
•The first compound microscope was
developed by Zacharias Janssen, in
Holland in 1595
•It was simply a tube with lenses at each
end
•Its magnification ranged from 3X to 9X.

5. World’s 2
nd
Microscope
•The 2
nd
microscope was developed
by Anton van Leeuwenhoek a Dutch
scientist
•Microscope was much better then
previous one
•Its magnification power was more
than 250X
•We can observe small organisms
under this microscope

6. Terms are Used In
Microscopy
•Magnification:
•The increase in the apparent size
of an object
•It is an important factor in
microscopy.

7. Terms are Used In
Microscopy
•Resolving Power/Resolution:
•The measure of the clarity of an
image
•It is the minimum distance at
which two objects can be seen as
separate objects
•Human naked eye can
differentiate between two points,
which are at least 0.1 mm apart
•If we place two objects 0.05 mm
apart, human eye would not be
able to differentiate them as two
separate Objects
•Magnification and resolution can
be increased with the help of
lenses

8. Light microscopy
and electron
microscopy
•Two types of
microscope i.e.
1.Light microscope
(LM)
2.Electron
microscope (EM)

9. Light
Microscope
•A light microscope works
by passing visible light
through a specimen
•It uses two glass lenses
•One lens produces an
enlarged image of the
specimen
•the second lens magnifies
the image and projects it
into viewer’s eye

10. Simple light microscope:
•The simple microscopeconsists of a single
lens traditionally called a loupe
•The most familiar present-day example is a
reading or magnifying glass

11. Compound Light
Microscope
•The compound light
microscope is a tool
containing two lenses,
which magnify, and a
variety of knobs used to
move and focus the
specimen
•Since it uses more than
one lens, it is sometimes
called the compound
microscope in addition to
being referred to as being a
light microscope.

12. Characteristics of
light microscope
•A light microscope can magnify objects only
about 1500 times without causing blurriness
•Its magnification is 1500X
•Its resolving power is 0.2 micrometer (μm)
•The image of bacterium can be magnified many
times
•Light microscope cannot show the details of its
internal structure

13. Electron Microscope
•It is the most advanced form of microscope
•First Electron Microscope is discovered by Ernst Ruska & Max Knoll
•In EM, object and lens are placed in a vacuum chamber
•a beam of electrons is passed through object
•Electrons pass through or are reflected from object and make image
•Electromagnetic lenses enlarge and focus the image onto a screen

14. Characteristics of electron
microscope
•Electron microscope has much higher resolving power than light microscope
•The most modern EM can distinguish objects as small as 0.2 nanometer (nm)
•It is a thousand-fold improvement over LM
•EM can magnify objects about 250,000 times
•Cells, organelles and even molecules like DNA and protein are much larger than single
atoms

15. Types of Electron
Microscope
•Biologists use two types of
electron microscopes
•Transmission Electron
Microscope (TEM)
•Scanning Electron
Microscope (SEM).

16. Transmission Electron Microscope (TEM):
•Used to view the internal structure
•Its magnification is about 250,000
•It shows 2D images
•Lenses are magnetic

17. Scanning Electron
Microscope (SEM):
•Used to study detail surface of cells or any other
objects
•The surface are coated with metal
•When electron hits the metal, it is reflected and
makes enlarged image
•Its shows us 3D images
•Its magnification is same as TEM
•It also have magnetic lenses

18. Staining
•Staining in biology: Adds
colored substances to cells
or tissues.
•Makes them visible under a
microscope.
•Aids in identifying and
studying specific
structures/components.

19. Principle Of Staining
Stains picked for
their affinity to
target molecules.
Interact with targets
through chemical
forces (e.g.,
electrostatic,
hydrogen bonds).
Specific binding
highlights
desired
structures.
Stains are
selective,
binding to
specific
components.
Minimize non-
specific
binding.
Enables
visualizing
specific
structures.
Staining adds
color for
contrast.
Helps
distinguish
target structures
from the
background.