Science 10 – Unit C - BIOLOGY
Chapter 1 – The Microscope
C1.3 & C1.4 - Development in imaging, staining, and cell research
Factors affecting the quality of an image in microscopy:
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
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Magnification
o improved with advancements in lens-making
o light microscopes used in labs today can now magnify
Contrast
o refers to
o it is contrast that allows the human eye to focus on different aspects of the image and
o cells by themselves are mostly colourless
o image quality has improved with:


Resolution
o the ability to
o the human eye is capable of resolving objects that are
o the higher the resolution of a microscope,
o similar to the resolution capabilities of a digital camera
Fluorescent microscopy
 fluorescent stains called GFP (green fluorescent protein) are introduced to the specimen
 different cell structures absorb stains in different amounts
 the specimen is subjected to UV light
 depending on the type of dye, the cell glows either
 unlike conventional staining,
Types of microscopy:

Brightfield microscopes
o light
o fixing and staining process kills the specimen
o you can’t view
o limited resoloution
o you can’t get any higher resolution than

Confocal technology
o uses lasers and computers to focus the light
o the later reflects off the object and back to the eyepiece
o you see
o computer software can be used to
o fluorescent stains work better with
confocal microscopes because
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Electron microscopy
o uses a fine beam of electrons instead
of light
o the electrons pass through different
materials at different rates, due to
o instead of lenses, EMs use
o Transmission Electron Microscope (TEM)
 electrons
 100X better magnification and resolution than light microscope
 difficult to
 specimens are fixed and stained, so
o Scanning Electron Microscope (SEM)
 good for observing
 the specimen is
 the electrons reflect off the gold and
 2X better image quality than the TEM
 uses computes to
 new SEMs permit the use of

Gene mapping
o with new imaging techniques comes new possibilities for
o gene mapping refers to
o an organism’s genome refers to all the information contained
o in 2001, the Human Genome Project published a
o could help us understand where cancer and other diseases
o also allows us to
 ethical arguments arise about the dangers of

Cell communication
o cells are open systems, meaning
o hormones are chemicals produced in one part of your body
 for example, the hormone adrenaline is produced in your brain, but acts all over
your body
 hormones and other transmitter chemicals form part of your cells’ communication
system
o receptors on the surface of the cells allow transmitters to attach to the cell and carry out
their function
 only transmitters
 similar to a
 certain viruses and bacteria can trick the cells by

in order for your immune system to fight off invaders, it must first
o better understanding of cell communication allows scientists and research companies to:
 diagnose diseases
 diagnose diseases
 make
 Homework
 Page 264 #1, Page 265 #10, 11
 Complete the following table:
Feature
Light microscope
illumination
focused by
how image is viewed
advantages
disadvantages
Electron microscope