|
.
|
- In 1665, Robert Hooke used the word cellls to describe the chamber like structures that he noticed while examining thin slices of cork under a microscope.
- In 1838, Matthias Schleiden, a botanist,, and Theodor Schwann, a zoologist, agreed that all plants and animals must be composed of cells.
- In 1859 , Rudolf Virchow proposed that aall cells must originate from other cells.
- - The discoveries of Schleiden, Schwann and Virchow have led to the Modern Cell Theory:
- ) All organism's are composed of one or more cells
- ) The cell is the basic unit of structure and function in organisms
- ) All cells are produced from other cells
- Cell size is restricted by the ability oof the cell's surface area to meet the demands of cell's interior or volume.
- Polar molecules contain an uneven balancce of "+" and "-" charges which attracts other polar molecules.
- Water H2O is a polar moleculee since the oxygen atom pulls electrons closer to one side of the molecule than hydrogen, creating positive and negative "poles".
-Nonpolar molecules have balanced atomic ccharges and are not attracted to polar molecules.
-Oil is a nonpolar molecule and is not atttracted to water.
- The Lipid bilayer of a cell membrane is made of oil to control water from disrupting the interior functions of the cell.
|
