Biology Lecture 11 - Biology Lecture 11 Cell is the...

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Biology Lecture 11 Cell is the simplest living unit Organisms can be unicellular or multicellular Units of measurement 1 meter = 100 cm = 1 million micrometers = 1 billion nanometers Atoms are smaller than 1 nm Molecules are almost 1 nm Macromolecules are anywhere from 1-10 nm Bacteria are between 1-10 micrometers Robert Hooke first saw cells in 1965 Microscopes help us view things to small to see with the naked eye Light microscope (LM)- visible light passes through a specimen and then through glass lenses which magnify the image i.Allows you to view living specimens, but the quality isn’t as good Electron microscope (EM)- focuses a light of electrons through or onto the surface of specimens. i. Scanning electron microscopes (SEMs) focus a beam of electrons onto the surface of a specimen, providing 3-D images ii. Transmission electron microscopes (TEMs) focus a beam of electrons through a specimen (mainly for studying internal structure of cells). Specimens are prepared to be able to see the cross sections and longitudinal sections
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Biology Lecture 11 - Biology Lecture 11 Cell is the...

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