1. NOTES:
INTRODUCTION TO CELLS

2. NOTES – CELL DISCOVERY
History of Cells
Robert Hooke: uses microscope to look at cork - called the chambers he saw “cells”
Anton van Leeuwenhoek: first to find microscopic living organisms

3. Mattias Schleiden: all plants are made of cells
Theodor Schwann: all animals are made of cells
Rudolf Virchow: all cells come from pre-existing cells

4. CELL THEORY: 3 parts
1. All organisms are composed of one or more cells

5. 2. The cell is the basic unit of structure and organization of living organisms

6. 3. All cells come from pre-existing cells

7. CELL TYPES: 2 basic kinds
both kinds have a plasma membrane (outer covering)
grouping is based on internal structures called ORGANELLES
1. PROKARYOTES
do not have internal organelles – only some DNA, ribosomes floating in cytoplasm – EX: bacteria

8. 2. Eukaryotes
has internal organelles surrounded by a membrane
EX: typical animal or plant cell
Eukaryote Prokaryote

9. THE PLASMA MEMBRANE
Plasma Membrane
(CELL MEMBRANE)
boundary between the cell and its environment
2 Functions
1. Separate & protect the cell from its environment
2. regulates what enters & leaves the cell
the process of maintaining the cells environment is called: HOMEOSTASIS

10. FLUID MOSAIC MODEL
Selective Permeability
the membrane allows certain molecules in while keeping other molecules out
allows the cell to maintain homeostasis

11. Cell Membrane Structure
Most molecules of the cell membrane are lipids
When a phosphate group replaces a fatty acid a PHOSPHOLIPID forms
Each phospholipid has a head with 2 tails
Head – attracts water
Tail – repels water

12. membrane is called a PHOSPHOLIPID BILAYER

13. phosphate + lipid keeps water out & in
only certain molecules are allowed in or out

14. The CELL WALL is the outer boundary of a plant cell
the cell wall is outside the cell membrane in plants
FUNCTIONS: support & protection
stiff/rigid structure