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Last weeks quizzes and reportsSee me for your quizzes and lab
reports before leaving, after cleaning up.
Grading questions etc.?
Office hours: Mon 11-1 Ramaley N-197
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Microscopy Properly use a microscope/camera. Compare resolution
& magnification. Identify types/structures of cells.Prepare for
quiz next week
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The Microscope Correct use and care: transport and lenses Parts
of the bright field microscope Magnification and resolution Types
of lenses Estimation of size
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The MicroscopeEach type of microscope has a specific function,
which makes them suitable for different types of tasks.Fig. 1:
dissecting, fluorescence, phase-contrast and electron
microscopes.
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Bright field microscopyLight is sent up from under stageLight
goes through condenser and is focused on object.Light goes through
object into objectives and object is magnifiedLight goes through
oculars to eye and is magnified again
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The Microscope
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The MicroscopeMagnification: number of times an object is
magnified by the lensesResolution: the ability of a microscope to
show to separate dots as discrete units
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The MicroscopeLenses:
Low power" objectives: are very useful to get overview images of
larger sections.
High power" objectives: are mostly for details and there are
more delicate (dry and wet lenses).
As the magnification increases in the lenses, the working
distance decreases.
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The MicroscopeLenses:
The Immersion lens (100X).
Used with oil because its refractive index is close to that of
glass, avoiding loss of light. Working distance very small
Dealing with oil1. Dont get oil on other lenses2. Dont use cover
slip with oil3. Wipe off oil with lens tissueDO NOT GO BACK TO
LOWER POWER OBJECTIVE
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What we are going to do?Take digital pictures of plant cells
Identify cellular components
Mount and dye cheek cells, identify components
Identify bacteria
Take pictures
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Example
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Cell Theory
Cells are the basic units of life All living organisms are
composed by cells Prokaryotic vs. Eukaryotic cell Animal vs. Plant
cell
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BiodiversityLiving organisms are organized into 3 domains
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BiodiversityToday, we will see examples of 2 of them 2
domains
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The CellPlant cell Remove a thin leaf from the tip of a Elodea
sp. plant Place the leaf on the microscope slide with a drop of
water Add a cover slip and soak up extra water with a tissue
Identify: cell wall, cell membrane, chloroplasts, central vacuole
and nucleus.
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The CellAnimal cell Take a toothpick and gently scrape the
inside of your cheek and around your gums Place a small drop of
water on a microscope slide and stir the content Evaporate the
water Pass the slide over a Bunsen burner Mark the area on the
other side Add two drops of methylene blue (60sec. and wash it off)
Dab off remaining water
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The CellProkaryotic cell: Bacteria Identify and obtain digital
images of rod-shaped and coccus-shaped bacteria
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Digital CamerasBe gentle, no jamming of cablesUpload photos,
choose the best for each (plant & cheek), e-mail to yourself,
and meRemove one eyepiece to use cameraSome cameras have damaged
USB ports, and require card readers to upload
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Bunsen burnersKeep slides right-side upNo oil on any lenses but
100x, wipeDr. Baseys demonstrationHints & Warnings
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