Instruments used to magnify & view objects 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” AKA cells & bacteria Simple Light Microscope, only 1 lens

Robert Hooke English scientist Compound light microscope 2 or more lenses Looked at cork (dead cells on oak bark) Saw 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 Plants are composed of cells Theodor Schwann Animals are composed of cells Summarized in the Cell Theory

Cell Theory

The Cell Theory: All organisms are composed of 1 or more cells. 3 Main Ideas: All organisms are composed of 1 or more cells. The cell is the basic unit of structure & organization of organisms. All cells come from preexisting cells.

Types of Microscopes

Types of Microscopes Light Microscope: what we use in lab Uses light to magnify Used to look at living cells Magnify: up to 1500x Electron Microscope: (1930-1940) Uses beams of electrons Magnify: up to 500,000x See inside of cells, look at structures 2 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 Uses 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: Eukaryotes: contain membrane-bounded organelles (ex. nucleus) Most multi-cellular organisms & some unicellular ones, like algae Complex cells 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/images/bacteria.gif