CELL HISTORY ROBERT HOOKE England 1665 observes slice

CELL HISTORY • ROBERT HOOKE (England) • 1665 observes slice of cork (bark from oak tree) with a 30 X microscope • Noticed “tiny boxes” in cork • Called them “CELLS”

CELL HISTORY • ANTON VAN LEEUWENHOEK (Netherlands) • Creates a microscope from polished sand 300 X • Observes “clear” pond water • Notices a world of tiny organisms- called them ANIMALCULES (actually single celled protists) • First to see living cells- 1675

CELL HISTORY • MATTHIAS SCHLEIDEN &THEODORE SCHWANN (Germany 1839) • SCHLEIDEN- plants made of cells • SCHWANN- animals made of cells • Put it all together= • Every living thing is composed of cells

CELL HISTORY • RUDOLPH VIRCHOW- Germany 1855 • Observed that cells come from other cells

THE CELL THEORY • All of this information led to the CELL THEORY • 1) All living things are composed of one or more cells • 2) Cells are the basic units of structure and function of organisms • 3) Cells come from the reproduction of existing cells

CELL SIZE Are elephant cells larger than ant cells?

NO • the small size allows materials to reach all cell parts • the surface area of the cell must be able to supply raw materials • volume will increase faster than surface area

Surface area : Volume • Surface area is area on surface of object- area of all sides • Volume is amount of space in an object • Cells want to maximize this ratio • Have a large enough surface area while keeping volume small