Transcript Important Tools in Biology

MICROSCOPE
18th Century
A compound microscope used in 18th-century
France. First developed in the late 16th century,
compound microscopes use two or more sets of
lenses to achieve high magnification.
TYPES OF MICROSCOPE
I. OPTICAL MICROSCOPES
Hooke’s Microscope
English scientist Robert Hooke built this microscope in the 17th
century and used it to conduct pioneering research. He discovered
the cell structure of plants by observing a thin slice of cork under
his microscope.
Important Tools in Biology
Microscopes – is an instrument that uses
lenses to produce an enlarged and
focused image of a specimen.
Two properties:
1. Magnification – is the ratio between
the image size and the object size.
2. Resolution (Resolving power) – refers
to the smallest degree of separation at
which two objects are viewed as distinct
from one another, rather than as a blurry,
single image.

Micron (µ)- unit of measurement used in
microscope study.
Conversion of Units:
1µ = 0.000001m
1µ = 0.001mm
Examples:
Range of Bacteria = 0.5 to 2µ
Range of some nerve cells = 1000µ
Types of Microscopes
1. Compound Light
Microscope – focuses
and bends visible light
through a specimen to
produce a magnified
image.
*Magnification = up to
1500x
*Resolution = 0.1 to
0.2µ
Computation for the size of specimen
TM =OLM x OL
Where:
TM = Total Magnification
OLM = Objective Lens Magnification
OL = Ocular Lens
Types of Microscopes
2. Stereomicroscope
(Dissecting Microscope)
– consists of two
eyepieces and two
objective lenses.
- used for dissecting
small specimens.
Magnification = ranging
from 4x to 50x
Types of Microscopes
3. Electron Microscope – uses a
beam of electrons instead of light
to create image.
- the beam of electrons is focused
using magnetic lenses.
Resolution power = about 1,000
times
Types of Electron Microscopes
a.
Transmission
Electron Microscope
(TEM) – uses a
magnetic field beam
to focus a beam of
electrons through a
thin section of the
specimen.
Magnification =
about 100,000 times
Types of Electron Microscopes
b. Scanning Electron
Microscope (SEM) –
gives a surface view
of a threedimensional
specimen by
bouncing electrons off
its surface.
Magnification = about
10,000 times
Types of Electron Microscopes
c. Scanning Tunneling
Microscope (STM) –
allows viewing of
atoms on the surface
of a solid.
Magnification = over 1
million times
OTHER SCIENTIFIC TOOLS
1.
Ultracentrifuge – a
machine used to
separate
suspended
particles in a
mixture.
OTHER SCIENTIFIC TOOLS
2. Chromatography –
used in separating
substances in a
mixture.
Types:
a. Paper
Chromatography
b. Column
Chromatography
OTHER SCIENTIFIC TOOLS
3. Electrophoresis –
used to separate
substances in a
mixture according to
how fast they move
when subjected to an
electric current.
- commonly used to
purify proteins based
on their sizes and
shapes.
OTHER SCIENTIFIC TOOLS
4. X-ray Diffraction –
useful for analysis of
protein crystals using
X-rays of a single
wavelength.
OTHER SCIENTIFIC TOOLS
5. Spectrophotometer –
used to determine the
amount of proteins or
nucleic acid present in
a solution.
- measures the
amount of light
absorbed by the
solution at specific
wavelength.
OTHER SCIENTIFIC TOOLS
6. Computer – useful
in storing vast
amounts of
information.
- also used to
organize data, make
long and complex
calculations and
make graphs to
summarize results.