1.3 - Microscopy Flashcards
(13 cards)
What structures cannot be seen without microscopes?
Extremely small structures such as cells cannot be seen without microscopes, which enlarge the image.
Who observed the first cells of cork and when?
Robert Hooke observed the first cells of cork in 1665 using a light microscope.
What are the characteristics of a light microscope?
It has two lenses, is usually illuminated from underneath, has a maximum magnification of 2000x, and a resolving power of 200nm.
What does resolving power affect?
Resolving power affects resolution: the ability to distinguish between two points.
What can be viewed using a light microscope?
Light microscopes are used to view tissues, cells, and large sub-cellular structures.
What was developed in the 1930s that enhanced viewing of sub-cellular structures?
The electron microscope was developed in the 1930s, enabling scientists to view deep inside sub-cellular structures.
What is used to form an image in an electron microscope?
Electrons are used to form an image because they have a much smaller wavelength than that of light waves.
What are the two types of electron microscopes?
The two types are scanning electron microscope (SEM) that creates 3D images and transmission electron microscope (TEM) that creates 2D images.
What is the maximum magnification and resolving power of electron microscopes?
They have a magnification of up to 2,000,000x and resolving power of 10nm (SEM) and 0.2nm (TEM).
What has the discovery of the electron microscope allowed scientists to do?
It has allowed scientists to view many organelles more clearly, especially very small structures such as ribosomes.
What have transmission electron microscopes been used to discover?
TEMs have been used to discover viruses such as poliovirus, smallpox, and Ebola.
Why are electron microscopes useful for identifying viruses?
Viruses are much smaller than bacteria and are very hard to identify using a standard light microscope.
What additional detail can electron microscopes provide?
Electron microscopes can examine proteins in much greater detail than can be achieved with a light microscope.
