microscopes instruments used to magnify & view objects
TRANSCRIPT
Anton van Leeuwenhoek
●1600’s
●1st view of “animalcules”oAKA cells & bacteria
●Simple Light Microscope, only 1 lens
Robert Hooke
●English scientist●Compound light microscopeo2 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 germanoPlants are composed of cells
●Theodor SchwannoAnimals are composed of cells
●Summarized in the 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
●Light Microscope: what we use in laboUses light to magnifyoUsed to look at living cellsoMagnify: up to 1500x
●Electron Microscope: (1930-1940)oUses beams of electronsoMagnify: up to 500,000xoSee inside of cells, look at structureso2 types
Scanning Electron Microscope: (SEM)
●Scan surfaces of cells, look at 3D shape
http://mse.iastate.edu/microscopy/whatsem.html
http://www.mos.org/sln/sem/diatom.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 MicroscopeoUses 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