microscopy- lecture #6 Flashcards
when were microscopes invented?
1950
who were the first 2 people to see and observe living cells?
Robert Hooke (1665)
Antony Van Leeuwenhoek (1674)
what did Antony Van Leeuwenhoek think he was viewing?
thought he was viewing living cells but turns out they were just artifacts
was the first to observe living cells
what did Robert Hooke do?
1st to see and describe living cells
father of cell theory but didn’t prove it
what are the 2 types of microscopy?
compound light microscopes and electron microscopes
the light microscope uses 2 lenses to observe specimens, how does it work?
light travels through the live specimen
then magnified through the objective lens
magnified again through the ocular lens
what do electron microscopes use instead of light?
uses beams of electrons
what do electron microscopes allow us to view?
internal cell structures and viruses
what are the 2 types of electron microscopes?
scanning electron microscope (SEM)
transmission electron microscope (TEM)
functions of SEM
can only view surface of an object
specimen must be coated with a film of heavy metal (electron dense)
wide range of magnifications
functions of TEM
examines internal cell structure
cell needs to undergo seconing (thinly cut)
the sections must be stained (improves contrast of different parts of the cell)
also inject resin to freeze all the parts of the cell in place
function of cell fractionation
cell fractionation takes apart and separates the major organelles so they can be studied in depth
what are the steps of cell fractionation?
tissue cells, blend/homogenization, homogenate produced, spin in centrifuge, pellet produced at the bottom of the cylindre, the liquid at the top goes into the centrifuge again and we’ll get smaller organelles each time
