SOL BIO 2a

 3 parts to the cell theory  1. The cell is the basic unit of life  2. All living things are made of cells  3. Cells come from pre-existing cells Cell division

 Fact: No portrait survives of Robert Hooke. His name is somewhat obscure today, due in part to the enmity of his famous, influential, and extremely vindictive colleague, Sir Isaac Newton! Hooke, however, was also temperamental!  Hooke was perhaps the single greatest experimental scientist of the seventeenth century. His interests knew no bounds, ranging from physics and astronomy, to chemistry, biology, and geology, to architecture and naval technology = an English polymath!  Micrographia, his book published in 1665, collection of microscopic observations

Hooke coined the biological term cell because his observations of the cork plant cells reminded him of monks’ cells which were called “cellula." cell Hooke’s Microscope -devised a compound microscope Cork cells

- Was a salesman for drapery cloth - Used lenses to check cloth quality - Began grinding his own lenses - After reading Hooke’s, Micrographia, he began using his single lenses to look at 1. Blood cells in Sperm cells in Algae cells in 1674 Spirogyra from a lake nearby 4. Bacteria cells in 1683 plaque from his teeth 5. Protista in 1703 Vorticella

- Was a single lens instrument inches big - Had to rest it against one’s forehead - Hooke called it “offensive to his eyes and very difficult to use!”

 Noticed a curious movement of small particles in water vacuoles “Brownian Movement” - the random, constant motion of atoms/molecules and particles  Named “the nucleus”  – a structure that Leeuwenhoek had documented 50 years earlier  Botanist

Studied nerve tissue - nerve cells named after him Schwann cells Interesting Fact: He met botanist Matthew Schleiden for dinner; both men were in their 30’s, during conversation comparing their ideas about cells … the similarities between their plants and animal studies became obvious and led to them theorizing: All living things are made up of cells

- German botanist, friend of Schwann - First a lawyer, then took up his hobby with plants full time - Published theory that all plant parts were made up of cells

 German scientist who theorized that all cells come from pre-existing cells  Rejected “spontaneous generation”  Rejected “Nordic race superiority” by studying cranial anthropology  Unfortunately, adamantly rejected the idea that disease came from bacteria, delaying the use of antiseptics

Little remembered fact As early as 1590: - Zaccharias Janssen and his father Hans Janssen 2 Dutch lens makers before Leeuwenhoek - started experimenting with these lenses … putting two together for magnification “COMPOUND MICROSCOPE”

-Hooke – a simple compound light microscope -Leeuwenhoek - simple single lenses, but very powerful … more than Hooke’s compound -Light provided first by a mirror reflecting light, then electrical lights added 1890 Mirror reflection Single eyepiece Electric light source Bi-ocular

- German co-inventors: Max Knott and Ernst Ruska - awarded half of the Nobel Prize for Physics in 1986 for his invention. Scanning Electron Microscope (SEM): - bounces electrons off of a whole gold- coated sample to create vivid 3-D images Transmission Electron Microscope (TEM): Transmission Electron Microscope (TEM): - bounces electrons off of a sliced sample to create very detailed internal images

Head of an Antartica mite X Pollen