History of the CellChapter 4

Discovery of Cells

Robert Hooke --- Discovered and named the first cell

Anton van Leeuwenhoek --- Discovered 1st living microscopic organisms.

Schleiden --- Concluded that all plants are made of cells.

Schwann – Concluded that all animals are made of cells.

Virchow --- Discovered all cells come from other cells

Cell Theory Parts 3 parts to the cell theory:

Cells are the basic unit of life All organisms are made of 1 or more cells All cells come from already existing cells

Cell Diversity

Size Most cells visible only with a microscope Cells are limited in size by ratio between outer surface

area & volume Surface area & volume do not increase at the same rate As size increases, volume increases faster than surface

area

Shape Cells come in varieties of shape Diversity reflects a diversity of functions. Ex. Nerve cells

Prokaryotic vs. Eukaryotic Prokaryotic = Unicellular; cells that lack

membrane-bound nucleus & other organelles. Example = bacteria cells

Eukaryotic = cells that contain membrane-bound nucleus & other organelles. Examples = plants & animal cells