Microscopes: Two Important Factors In Microscopy

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Pages: 16

Chapter 4


Two important factors in microscopy are:

1) Magnification: an increase in the object’s apparent size compared with its actual size.
2) Resolving Power: the ability of an optical instrument to show two objects are separate.

Three types of microscopes:

1) Light Microscope (LM) M: 1000x RP 0,2 micrometer (small bacterial cell)
2) Electron Microscope (EM) uses a beam of electrons to resolve electrons, better resolving powers than light microscope M:100,000x RP 0,2 nanometer

A) Scanning Electron Microscope (SEM) Surface
B) Transmission Electron Microscope (TEM) Internal Structure

Preparing specimen for electron microscope hard, light microscope still very useful as a window on living cells.

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The Golgi receives proteins from the ER via vesicles, finishes processing the proteins, and then dispatches them in vesicles. One side receiving, one side shipping.


A lysosome is a sac of digestive enzymes found in animal cells, developed from vesicles that bud off from the Golgi. Enzymes within a lysosome can break down large molecules. They aid both digesting as recycling. Two lysosomes: food and central, digesting food and digesting damaged rganelles.


Vacuoles are sacs that bud from the ER, Golgi, or plasma membrane. Food vacuoles but especially important in plants. Include the contractile vacuoles that expel water from certain freshwater protists and the large, multifunctional central vacuoles of plant cells.

Chloroplasts and Mitochondria: Energy Conversion

Two organelles act as cellular power stations: chloroplasts and mitochondria.

Chloroplasts = synthesis
Mitochondria = harvests energy from sugars and other food molecules and concerts it into another form of chemical energy called ATP, found in most eukaryotic cells.

Shared future is they both contain DNA that encodes some of their proteins. This DNA is evidence that evolved from free living prokaryotes in the distant past.

The Cytoskeleton

Infrastructure of the cells. Serves as both skeleton and “muscles”. Maintains cell shape, important