The Cell Structure and Function
Cells
- All organisms are made up of cells
- Cells are the simplest collection of matter
that can be alive
- Cells can differ substantially from one
another yet they share common features
Microscope
- Used to visualize cells
- 3 important parameter of microscopy
• Magnification
o Ratio of an object’s image size to
its real size
• Resolution
o Measure of the clarity of the
image
• Contrast
o Visible differences in brightness
between parts of the sample
Light microscope
- Visible light passes through a specimen
and then through the glass lenses
- Lenses refract the light -> image is
magnified
- Can magnify up to about 1000 times the
size of the actual specimen
Light microscope
- Brightfield
- Phase-contrast
- Differential-interference-contrast
- Florescence
- Confocal
- Deconvolution
- Super-resolution
Electron microscope
- Used to study subcellular structures
- 2 types
• Scanning electron microscope
o Focus the beams of electrons on
the surface of specimen
o Provide 3D image
• Transmission electron microscope
o Used to study the internal
structure of cells
Electron microscope
- Scanning
- Transmission
Cell fractionation
- Takes cells apart and separates the major
organelles from one another
- Enables scientists to determine the
function of each organelles
