Transcript Microscopes
Microscopes Instruments used to magnify & view objects In the beginning… Diseases were thought to be caused by “supernatural spirits” and “curses” Anton van Leeuwenhoek ●1600’s ●1st view of “animalcules” oAKA cells & bacteria ●Simple Light Microscope, only 1 lens Robert Hooke ●English scientist ●Compound light microscope o2 or more lenses ●Looked at cork (dead cells on oak bark) oSaw small geometric shapes, named them CELLS ●Cells-> are the basic units of all living things ●http://www.wwnorton.com/nael/18century/topic_3/microscope.htm What did he see? http://www.cbs.dtu.dk/staff/dave/roanoke/bio101ch05.htm Then What? ●1830’s ●More scientists used Hooke’s ideas to explore the natural world ●Matthias Shleiden, a german oPlants are composed of cells ●Theodor Schwann oAnimals are composed of cells ●Summarized in the Cell Theory Cell Theory The Cell Theory: 3 Main Ideas: 1.All organisms are composed of 1 or more cells. 2.The cell is the basic unit of structure & organization of organisms. 3.All cells come from preexisting cells. Types of Microscopes Types of Microscopes ●Light Microscope: what we use in lab oUses light to magnify oUsed to look at living cells oMagnify: up to 1500x ●Electron Microscope: (1930-1940) oUses beams of electrons oMagnify: up to 500,000x oSee inside of cells, look at structures o2 types Scanning Electron Microscope: (SEM) ●Scan surfaces of cells, look at 3D shape http://www.mos.org/sln/sem/diatom.html http://mse.iastate.edu/microscopy/whatsem.html Transmission Electron Microscope (TEM) ●Look at structures within the cell http://en.wikipedia.org/wiki/Transmission_electron_microscope New Technology ●New models & helpful techniques all the time ●Example: Scanning Tunneling Microscope oUses flow of electrons to create computer images of atoms on the surface of a molecule www.chem.utoronto.ca/staff/DHIRANI/index.htm The Cell: ●With better microscopes, discovered that cells contain small specialized structures called organelles ●Each organelle has a specific function within a cell Types of Cells: ● 2 broad groups: 1.Eukaryotes: contain membrane-bounded organelles (ex. nucleus) Most multi-cellular organisms & some unicellular ones, like algae Complex cells 2.Prokaryotes: do not contain membrane-bound organelles (ex. No nucleus, but nucleoid region when chromatin is stored). Example: bacteria Less complex Many functions occur on cell membrane What do they look like? http://en.wikipedia.org/wiki/Eukaryotic http://www.earthlife.net/prokaryotes/im ages/bacteria.gif