1. Cells The Basic Units of Life

2. Cell Theory  Robert Hooke was the first person to describe cells in 1665.  He observed cork cells and plant cells, which are easier to see because of a cell wall.  Animal cells are harder to see, so he thought animals weren’t made up of cells since he couldn’t see them.

3. Anton van Leeuwenhoek  Discovered animalcules (which means little animals)  Now known as Protists (single-celled organisms)  Discovered cells in animal blood.  Found differences between blood cells of different animals.  First person to see bacteria

4. Cell Theory Matthias Schleiden and Theodor Schwann  Schleiden studied plants – Discovered all plants are made of cells  Schwann studied animals – discovered that all animal tissue is made of cells.  Schwann wrote first 2 parts of cell theory  All organisms are made of one or more cells  The cell is the basic unit of all living things

5. Cell Theory  Rudolf Virchow added the 3 rd part to the cell theory in 1858  All cells come from existing cells

6. Common cell parts  There are many different types of cells –  But all cells have a few parts in common  Cell membrane and cytoplasm  Organelles  Genetic material

7. Cell Membrane & Cytoplasm  All cells are surrounded by a cell membrane  The cell membrane is a protective layer that covers the cell’s surface and acts as a barrier  It also controls materials going into and out of the cell  Cytoplasm is the fluid inside a cell

8. Organelles  Structures that perform specific functions within the cell.  Most are surrounded by membranes  Some float in the cytoplasm  Some are attached to membranes or other organelles

10. Genetic Material  All cells contain DNA  DNA is the genetic material that carries information needed to make new cells and new organisms  DNA is passed from parent to offspring and controls the activities of a cell

11. 2 Types of Cells  Prokaryotes and eukaryotes  Prokaryotes are single-celled organisms that do not have a nucleus or membrane- bound organelles  Eukaryotes are an organism made of cells that have a nucleus enclosed by a membrane

12. Prokaryotes  Single-celled organism  Do not have a nucleus  Ex: Bacteria and Archaea  Bacteria are the most common prokaryote  No Nucleus, no membrane-covered organelles  Do have ribosomes, and a strong cell wall

13. Eukaryotes  Largest cells – 10 times larger than bacterial cells  Contain a nucleus and membrane-bound organelles  All living things that are not bacteria or archaea are made up of one or more eukaryotic cells  Many eukaryotic organisms are multi- cellular (many cells)(plants, animals, fungi)