Important Tools in Biology

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Microscopy
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MICROSCOPE 18th Century
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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.
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TYPES OF MICROSCOPE
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I. OPTICAL MICROSCOPES
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Hookes Microscope
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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.
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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.

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• 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

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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

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• Computation for the size of specimen
• TM OLM x OL
• Where
• TM Total Magnification
• OLM Objective Lens Magnification
• OL Ocular Lens

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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

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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

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Types of Electron Microscopes

• 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

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Types of Electron Microscopes

• b. Scanning Electron Microscope (SEM) gives a
  surface view of a three-dimensional specimen by
  bouncing electrons off its surface.
• Magnification about 10,000 times

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Types of Electron Microscopes

• c. Scanning Tunneling Microscope (STM) allows
  viewing of atoms on the surface of a solid.
• Magnification over 1 million times

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OTHER SCIENTIFIC TOOLS

1. Ultracentrifuge a machine used to separate
   suspended particles in a mixture.

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OTHER SCIENTIFIC TOOLS

• 2. Chromatography used in separating substances
  in a mixture.
• Types
• Paper Chromatography
• Column Chromatography

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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.

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OTHER SCIENTIFIC TOOLS

• 4. X-ray Diffraction useful for analysis of
  protein crystals using X-rays of a single
  wavelength.

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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.

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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.