1. Cell Discovery Unknown before the invention of the microscope
Cells too small to see with eyes
Robert Hooke
1665
Simple microscope to look at cork
Looked like “cells” or small rooms
Anton van Leeuwenhoek
1685
Designed his own microscope and looked at single celled organisms

2. Cell Theory A summary of experimental findings about cells
All living things are composed of one or more cells
Cells are the basic unit of structure and organization of all living organisms
Cells arise only from previously existing cells, with cells passing on copies of their genetic material

3. Prokaryotic Cells No organelles No nucleus Single celled Bacteria
Cellular functions take place anywhere in cell
No nucleus
Genetic material (DNA) is free floating in cell
DNA is circular
Single celled
Bacteria

4. Eukaryotic Cells Have organelles Have nucleus
Membrane bound structures
Allows cellular functions to take place in specific places
Have nucleus
Contains genetic information
DNA is linear
Multicellular animals or plants
Some unicellular
Yeast and algae

5. Both Prokaryotic and Eukaryotic
Have cell membranes

6. Prokaryotic and Eukaryotic1. 2. 3. 4.

7. Plasma Membrane Separate the cell from the environment
Selective Permeability
Allows some molecules to pass through
Keeps some molecules in
Keeps some molecules out

9. Structure of the Plasma Membrane
Phospholipid bilayer
Two layers of phospholipids
Water-loving “heads”
Water-hating “tails”
Water soluble substances do not move through
Transport proteins
Move some things in or out of the cell
Like tunnels through the membrane

10. What else is stuck in the plasma membrane?
Cholesterol
Maintains fluidity
Carbohydrates
Help identify cells

11. Cell Organelles – All Eukaryotes
Nucleus – Control Center
Ribosomes - Makes proteins
Endoplasmic Reticulum- Makes proteins
Golgi Apparatus – Packages proteins
Vacuole – Stores cell materials
Mitochondria- Supplies energy to cell
Cell membrane - Flexible boundary

12. Eukaryotic Cell Structures Found….
Only in Animal Cells
Lysosome
Digestive enzymes
Centriole
Plays a role in cell division
Only in Plant Cells
Cell Wall
Inflexible barrier
Chloroplast
Where photosynthesis takes place

15. Cell Organelles Cell Membrane Phospholipid bilayer Barrier
Selective permeability
Cytoplasm
“Insides” of the cell
Semi fluid

16. Cell Organelles Cytoskeleton Supports organelles Protein
Helps transport cell products
Nucleus
Contains DNA
Double membrane

17. Endoplasmic Reticulum
Cell Organelles
Ribosomes
Produce protein
Made of RNA and protein
Float free or attached to Endoplasmic Reticulum
Endoplasmic Reticulum
Synthesizes macromolecules
Rough – has ribosomes attached
Smooth – no ribosomes

18. Cell Organelles Golgi Apparatus Modifies proteins
Packages proteins for transport out of cell
Mitochondria
Produces energy for the cell
Breaks down polysaccharides

19. Cell Organelles Lysosome Digests foreign invaders
Recycles cell products
Vacuole
Storage of cell products
Storage of waste products
Plants have a large vacuole

20. Cell Organelles Chloroplast Plants only Site of photosynthesis
Gives plants green color
Cell Wall
Plants only
Gives plants structure
Made of cellulose