2. Facts  Cells are the fundamental units of life.  All living organisms are composed of and depend on cells to function normally.  Scientists estimate that our bodies contain anywhere from 75 to 100 trillion cells.  Cells do everything from providing structure and stability to providing energy and a means of reproduction for an organism.

3. There are more bacterial cells in the body than human cells.  Scientists have estimated that about 95% of all the cells in the body are bacteria

4. Cells contain genetic material.  Cells contain DNA

5. There are many types of cells.

6. Different types of cells reproduce through different methods.  Most prokaryotic cells reproduce by a process called binary fission (cloning process)  Eukaryotic organisms go through mitosis.

7. Groups of similar cells form tissues.

8. Cells have varying life spans.  Cells have different life spans based on the type and function of the cell.  Certain cells of the digestive tract live for only a few days, while some immune system cells can live for six weeks.  Pancreatic cells can live for as long as a year.

9. Cells commit suicide.  When a cell becomes damaged or undergoes some type of infection, it will self destruct by a process called apoptosis.  Apoptosis keeps the body’s natural process of cell reproduction in check.  A cell’s inability to undergo apoptosis can result in the development of cancer.

11. Two Main Types of Cells  Prokaryotic  Lack a membrane bound nucleus  DNA is not found in the nucleus  Shapes: rod, spherical, spiral  Bacteria

12.  Eukaryotic  Membrane bound nucleus  Many organelles that perform functions  Kingdoms: Animalia, Plantae, Fungi, Protista

13. Plant and Animal Cells AnimalPlant  Have a cell membrane  Nucleus  Other organelles  Cell membrane and nucleus  Have a rigid cell wall to hold its shape  Chloroplasts for photosynthesis