• Science – a systematic body of knowledge; a way of finding truth Lecture Notes:
• Technology – product of science
_______________________________________________________________________
• Society – composed of people interacting together
_______________________________________________________________________
Branches of Science
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
Branches of Science: _______________________________________________________________________
• Formal Science – analysis of numerical data and reasoning _______________________________________________________________________
• Natural Science – study of nature and universe
a. Physical Science – physical entities/non-living things _______________________________________________________________________
b. Biological Science – study of living tings _______________________________________________________________________
• Social Science – concerned with society and human interactions
_______________________________________________________________________
Scientific Method – a systematic approach to solve a problem _______________________________________________________________________
1. Making OBSERVATIONS
Observations are data gathered through the use of senses and some _______________________________________________________________________
tools. _______________________________________________________________________
Inference is getting an idea from an observation.
2. Identifying the PROBLEM _______________________________________________________________________
3. RESEARCHING _______________________________________________________________________
4. Formulating a HYPOTHESIS
Hypothesis is an educated guess. _______________________________________________________________________
5. EXPERIMENTING _______________________________________________________________________
• Independent variable – the factor that is manipulated
• Dependent variable – the factor that is affected by the independent _______________________________________________________________________
variable _______________________________________________________________________
• Fair testing is when you change only one variable in an experiment that is
_______________________________________________________________________
an independent variable.
6. ANALYZING the result _______________________________________________________________________
7. Making CONCLUSION
_______________________________________________________________________
Theory – hypothesis that has been tested and consistently supported by
data. _______________________________________________________________________
Law – summary of all experimental results.
_______________________________________________________________________
Units of Measurement in Cell Biology _______________________________________________________________________
• Cells are roughly microns in size
_______________________________________________________________________
• 1 micron (µ) = 10-3 millimeters = 10-6 meters
,• E. coli cells are usually around 3 microns Lecture Notes:
• Yeast cells are little balls around 2 microns in diameter
_______________________________________________________________________
• Most human cells are roughly 20 microns across, with roughly nuclei about 10
microns in diameter. _______________________________________________________________________
Nanometer _______________________________________________________________________
• The basic length scale used to describe molecules is a nanometer
• 1 nanometer (nm) = 10-9 meters _______________________________________________________________________
• Many biomolecules are made out of chemical units (e.g. nucleotides, amino acids) _______________________________________________________________________
which are around 1 nm in size, meaning that they are a few atoms across.
Angstrom _______________________________________________________________________
• 1 Angstrom (A) = 10-10 m = 0.1 nanometer _______________________________________________________________________
• Atoms are roughly Angstroms in size
• A hydrogen atom is about 1 A in diameter, a carbon atom is about 2 A in _______________________________________________________________________
diameter). _______________________________________________________________________
Types of Microscope _______________________________________________________________________
a. Light Microscopy _______________________________________________________________________
➢ The light microscope allows us to magnify cells up to 1000 times and to
resolve details as small as 0.2 mm _______________________________________________________________________
➢ A bright light must be focused onto the specimen by lenses in the _______________________________________________________________________
condenser
➢ Specimen must be carefully prepared to allow light to pass through it. _______________________________________________________________________
➢ Appropriate set of lenses (objective and eyepiece) must be arranged to _______________________________________________________________________
focus an image of the specimen in the eye.
b. Fluorescence Microscopy _______________________________________________________________________
➢ Fluorescent dyes used for staining cells are detected with the aid of a _______________________________________________________________________
fluorescence microscope.
➢ The illuminating light is passed through two sets of filters. _______________________________________________________________________
➢ The first filters the light before it reaches the specimen, passing only _______________________________________________________________________
those wavelengths that excite the particular fluorescent dye.
➢ The second filters blocks out this light and passes only those wavelengths _______________________________________________________________________
emitted when the dye fluoresces. _______________________________________________________________________
➢ Dyed objects show up in bright color on a dark background.
c. Confocal Microscopy _______________________________________________________________________
➢ A confocal microscope is a specialized type of fluorescence microscope _______________________________________________________________________
that builds up an image by scanning the specimen with a laser beam.
➢ The beam is focused onto a single point at a specific depth in the _______________________________________________________________________
specimen, and a pinhole aperture in the detector allows only _______________________________________________________________________
fluorescence emitted from this same point to be included in the image.
➢ Scanning the beam across the specimen generates a sharp image of the _______________________________________________________________________
plane of focus—an optical section. _______________________________________________________________________
➢ A series of optical sections at different depths allows a three-dimensional
image to be constructed. _______________________________________________________________________
, ➢ An intact insect embryo is shown here stained with a fluorescent probe Lecture Notes:
for actin (a filamentous protein).
_______________________________________________________________________
➢ Conventional fluorescence microscopy gives a blurry image due to the
presence of fluorescent structures above and below the plane of focus. _______________________________________________________________________
➢ Confocal microscopy provides an optical section showing the individual
_______________________________________________________________________
cells clearly.
d. Transmission Electron Microscopy _______________________________________________________________________
➢ The transmission electron microscope (TEM) is in principle similar to a
_______________________________________________________________________
light microscope, but it uses a beam of electrons instead of a beam of
light, and magnetic coils to focus the beam instead of glass lenses. _______________________________________________________________________
➢ The specimen, which is placed in a vacuum, must be very thin. Contrast is
_______________________________________________________________________
usually introduced by staining the specimen with electron-dense heavy-
metals that locally absorb or scatter electrons, removing them from the _______________________________________________________________________
beam as it passes through the specimen.
_______________________________________________________________________
➢ The TEM has a useful magnification of up to a million-fold and with
biological specimens can resolve details as small as about 2 nm. _______________________________________________________________________
e. Scanning Electron Microscopy
_______________________________________________________________________
➢ In the scanning electron microscope (SEM) the specimen, which has been
coated with a very thin film of a heavy metal, is scanned by a beam of _______________________________________________________________________
electrons brought to a focus on the specimen by the electromagnetic
_______________________________________________________________________
coils that, in electron microscopes, act as lenses.
➢ The quantity of electrons scattered or emitted as the beam bombards _______________________________________________________________________
each successive point on the surface of the specimen is measured by the
_______________________________________________________________________
detector, and is used to control the intensity of successive points in an
image built up on a video screen. _______________________________________________________________________
➢ The microscope creates striking images of three-dimensional objects with
_______________________________________________________________________
great depth of focus and can resolve details down to somewhere
between 3 nm and 20 nm, depending on the instrument. _______________________________________________________________________
_______________________________________________________________________
Parts of Compound Microscope
• Eyepiece— the part you look at with your eye. Usually 4x to 15x magnification. _______________________________________________________________________
• Body Tube – reflects light up to the viewers eye
_______________________________________________________________________
• Arm – used to safely transport microscope
• Revolving Nosepiece – allows for quick change of objectives _______________________________________________________________________
• Low Power Objective – The first lens you use when doing proper microscope work. _______________________________________________________________________
Usually 10 X
• High Power Objective – The highest magnification used. Usually 40 X. NEVER use _______________________________________________________________________
the course adjustment when using this lens. _______________________________________________________________________
• Stage – slides are placed on this
• Stage Clips – use to keep the slide in place. _______________________________________________________________________
• Coarse Adjustment knob – use to make large changes/locating specimen _______________________________________________________________________
• Fine Adjustment knob - use to small adjustments of focus/sharpen the image
_______________________________________________________________________
• Diaphragm – use to vary the amount of light passing through the slide
• Technology – product of science
_______________________________________________________________________
• Society – composed of people interacting together
_______________________________________________________________________
Branches of Science
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
Branches of Science: _______________________________________________________________________
• Formal Science – analysis of numerical data and reasoning _______________________________________________________________________
• Natural Science – study of nature and universe
a. Physical Science – physical entities/non-living things _______________________________________________________________________
b. Biological Science – study of living tings _______________________________________________________________________
• Social Science – concerned with society and human interactions
_______________________________________________________________________
Scientific Method – a systematic approach to solve a problem _______________________________________________________________________
1. Making OBSERVATIONS
Observations are data gathered through the use of senses and some _______________________________________________________________________
tools. _______________________________________________________________________
Inference is getting an idea from an observation.
2. Identifying the PROBLEM _______________________________________________________________________
3. RESEARCHING _______________________________________________________________________
4. Formulating a HYPOTHESIS
Hypothesis is an educated guess. _______________________________________________________________________
5. EXPERIMENTING _______________________________________________________________________
• Independent variable – the factor that is manipulated
• Dependent variable – the factor that is affected by the independent _______________________________________________________________________
variable _______________________________________________________________________
• Fair testing is when you change only one variable in an experiment that is
_______________________________________________________________________
an independent variable.
6. ANALYZING the result _______________________________________________________________________
7. Making CONCLUSION
_______________________________________________________________________
Theory – hypothesis that has been tested and consistently supported by
data. _______________________________________________________________________
Law – summary of all experimental results.
_______________________________________________________________________
Units of Measurement in Cell Biology _______________________________________________________________________
• Cells are roughly microns in size
_______________________________________________________________________
• 1 micron (µ) = 10-3 millimeters = 10-6 meters
,• E. coli cells are usually around 3 microns Lecture Notes:
• Yeast cells are little balls around 2 microns in diameter
_______________________________________________________________________
• Most human cells are roughly 20 microns across, with roughly nuclei about 10
microns in diameter. _______________________________________________________________________
Nanometer _______________________________________________________________________
• The basic length scale used to describe molecules is a nanometer
• 1 nanometer (nm) = 10-9 meters _______________________________________________________________________
• Many biomolecules are made out of chemical units (e.g. nucleotides, amino acids) _______________________________________________________________________
which are around 1 nm in size, meaning that they are a few atoms across.
Angstrom _______________________________________________________________________
• 1 Angstrom (A) = 10-10 m = 0.1 nanometer _______________________________________________________________________
• Atoms are roughly Angstroms in size
• A hydrogen atom is about 1 A in diameter, a carbon atom is about 2 A in _______________________________________________________________________
diameter). _______________________________________________________________________
Types of Microscope _______________________________________________________________________
a. Light Microscopy _______________________________________________________________________
➢ The light microscope allows us to magnify cells up to 1000 times and to
resolve details as small as 0.2 mm _______________________________________________________________________
➢ A bright light must be focused onto the specimen by lenses in the _______________________________________________________________________
condenser
➢ Specimen must be carefully prepared to allow light to pass through it. _______________________________________________________________________
➢ Appropriate set of lenses (objective and eyepiece) must be arranged to _______________________________________________________________________
focus an image of the specimen in the eye.
b. Fluorescence Microscopy _______________________________________________________________________
➢ Fluorescent dyes used for staining cells are detected with the aid of a _______________________________________________________________________
fluorescence microscope.
➢ The illuminating light is passed through two sets of filters. _______________________________________________________________________
➢ The first filters the light before it reaches the specimen, passing only _______________________________________________________________________
those wavelengths that excite the particular fluorescent dye.
➢ The second filters blocks out this light and passes only those wavelengths _______________________________________________________________________
emitted when the dye fluoresces. _______________________________________________________________________
➢ Dyed objects show up in bright color on a dark background.
c. Confocal Microscopy _______________________________________________________________________
➢ A confocal microscope is a specialized type of fluorescence microscope _______________________________________________________________________
that builds up an image by scanning the specimen with a laser beam.
➢ The beam is focused onto a single point at a specific depth in the _______________________________________________________________________
specimen, and a pinhole aperture in the detector allows only _______________________________________________________________________
fluorescence emitted from this same point to be included in the image.
➢ Scanning the beam across the specimen generates a sharp image of the _______________________________________________________________________
plane of focus—an optical section. _______________________________________________________________________
➢ A series of optical sections at different depths allows a three-dimensional
image to be constructed. _______________________________________________________________________
, ➢ An intact insect embryo is shown here stained with a fluorescent probe Lecture Notes:
for actin (a filamentous protein).
_______________________________________________________________________
➢ Conventional fluorescence microscopy gives a blurry image due to the
presence of fluorescent structures above and below the plane of focus. _______________________________________________________________________
➢ Confocal microscopy provides an optical section showing the individual
_______________________________________________________________________
cells clearly.
d. Transmission Electron Microscopy _______________________________________________________________________
➢ The transmission electron microscope (TEM) is in principle similar to a
_______________________________________________________________________
light microscope, but it uses a beam of electrons instead of a beam of
light, and magnetic coils to focus the beam instead of glass lenses. _______________________________________________________________________
➢ The specimen, which is placed in a vacuum, must be very thin. Contrast is
_______________________________________________________________________
usually introduced by staining the specimen with electron-dense heavy-
metals that locally absorb or scatter electrons, removing them from the _______________________________________________________________________
beam as it passes through the specimen.
_______________________________________________________________________
➢ The TEM has a useful magnification of up to a million-fold and with
biological specimens can resolve details as small as about 2 nm. _______________________________________________________________________
e. Scanning Electron Microscopy
_______________________________________________________________________
➢ In the scanning electron microscope (SEM) the specimen, which has been
coated with a very thin film of a heavy metal, is scanned by a beam of _______________________________________________________________________
electrons brought to a focus on the specimen by the electromagnetic
_______________________________________________________________________
coils that, in electron microscopes, act as lenses.
➢ The quantity of electrons scattered or emitted as the beam bombards _______________________________________________________________________
each successive point on the surface of the specimen is measured by the
_______________________________________________________________________
detector, and is used to control the intensity of successive points in an
image built up on a video screen. _______________________________________________________________________
➢ The microscope creates striking images of three-dimensional objects with
_______________________________________________________________________
great depth of focus and can resolve details down to somewhere
between 3 nm and 20 nm, depending on the instrument. _______________________________________________________________________
_______________________________________________________________________
Parts of Compound Microscope
• Eyepiece— the part you look at with your eye. Usually 4x to 15x magnification. _______________________________________________________________________
• Body Tube – reflects light up to the viewers eye
_______________________________________________________________________
• Arm – used to safely transport microscope
• Revolving Nosepiece – allows for quick change of objectives _______________________________________________________________________
• Low Power Objective – The first lens you use when doing proper microscope work. _______________________________________________________________________
Usually 10 X
• High Power Objective – The highest magnification used. Usually 40 X. NEVER use _______________________________________________________________________
the course adjustment when using this lens. _______________________________________________________________________
• Stage – slides are placed on this
• Stage Clips – use to keep the slide in place. _______________________________________________________________________
• Coarse Adjustment knob – use to make large changes/locating specimen _______________________________________________________________________
• Fine Adjustment knob - use to small adjustments of focus/sharpen the image
_______________________________________________________________________
• Diaphragm – use to vary the amount of light passing through the slide
