BIOC17H3 Lecture Notes - Lecture 1: Micrographia, Cardiovascular Disease, Electron Microscope
5 Jul 2018
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BIOC17 LECTURE NOTES
LECTURE #1
-20th century associated microbes with disease
-our immune system doesn't work well if we have too many of them
-notion of microbes evolved
-microbiology: the scientific study of microorganisms and their effects
oeffects in terms of environment/physiology/technology/capacity to
produce food and commodities
What is a microbe?
-Organisms too small to be seen by the unaided eye
-Small organisms that are relatively simple in construction
oSimple organization:
1. Lack of highly differentiated cells
come from a specific type of cell; no differentiation of
different cells to form tissues
2. Unicellular or multicellular organization
multicellular
organization (eg.
microbial colonies)
3. Lack of distinct tissues
-b/c didn’t have technology for viewing
MOs, we had this general definition
-note: while they are simple in construction,
they are still sophisticated
-Microbial world is anything that goes
below 100micrometeres to 1 micrometre
oBelow 1micrometre = nanoworld
Magnification and resolution
-compound microscope has 2 sets of lenses
find more resources at oneclass.com
find more resources at oneclass.com
-light goes through
lenses --> goes
through
condenser -->
onto specimen -->
into eye
--mag. can be done
for 1000x
-magnification
depends on the
power of the ocular
X the power of the
objective
-resolving power
othe resolving power of optical systems
is its ability to distinguish (form a clear
image) between small objects in close
proximity
oour eyes’ resolving pwer is 0.1mm
(100micrometer) 2 objects sep. by
1mm canot be clearly distinguished by
our eye (will look like one object)
thus: we can’t form images of microbes
-because light diffracts, when 2 objects are too close (and are too small), the
image will merge --> cannot distinguish between them
-if have high resolution, will be able to correct for the light diffraction --> higher
resolution will give image similar to the real object
-- so: resolving power of instrument is important to be able to form clear images of
objects that are very close
Limit of Resolution
find more resources at oneclass.com
find more resources at oneclass.com
-the resolution of a
microscope depends on the
numerical aperture (NA) of
the optical components, and
the wavelength of light ()
-the numerical aperture is given
by its lens system
-the objective and the
condenser have numerical
aperture
-numercial aperture is its
ability to gather light --> the
aperture is given in the lens
-if we use the shortest
wavelength of visible light
(400nm), an NA of 1.45 and
a condenser with an NA of
0.96, the Limit of Resolution would be 203 nm
-see 100x magnification with an aperture
of 1.3 (in the figure)
-aperature is related to diameter of the
objective lens
-larger diameter = colllect more light
-smaller wavelength used to generate
image, the lower the bending will be
--> will lead to good image
-use immersion oil to increase resolving
power of microscope; immerse
objective lens and specimen in oil
(with high refractive index) so that
the numerical aperture of the
objective lens increases
-use shortest wavelength because it will
result in a lower limit of resolutionzuse
400nm
-an optical microscope is not good if you want to view a microbe smaller than
400nm
-if want to study structure in microbial cell (organelles), need more powerful
microscopes (those structures are much smaller than 400nm)
-if we use e- wavelengths (1.23nm), then instead of applying lenses, we can apply
the wavelength to the microscope (using magnets), we can get a very high
resolution image results in an increase power of resolution and an decreased
limit of resolution
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Our immune system doesn"t work well if we have too many of them. Microbiology: the scientific study of microorganisms and their effects: effects in terms of environment/physiology/technology/capacity to produce food and commodities. Organisms too small to be seen by the unaided eye. Small organisms that are relatively simple in construction: simple organization: Lack of highly differentiated cells come from a specific type of cell; no differentiation of different cells to form tissues. Lack of distinct tissues b/c didn"t have technology for viewing. Note: while they are simple in construction, they are still sophisticated. Microbial world is anything that goes below 100micrometeres to 1 micrometre: below 1micrometre = nanoworld. Compound microscope has 2 sets of lenses. Light goes through lenses --> goes through condenser --> onto specimen --> into eye. Magnification depends on the power of the ocular. 1mm canot be clearly distinguished by our eye (will look like one object) thus: we can"t form images of microbes.
