2. Cells Part I Cells I

3. Living Things:  Highly organized  Convert energy for their own use  Control internal environment (Homeostasis)  Have adaptations  Respond to stimuli  Grow  Reproduce  Have emergent properties

4.  Characteristics of Living Things Characteristics of Living Things

5. Discovery of Cells 17 th Century Robert Hooke observed cork in a microscope. Anton van Leeuwenhoek described “animalcules” he found in tooth plaque.

6. Cell Theory 1. The cell is the smallest unit of life. 2. All organisms are made from one or more cells. 3. Cells arise from pre-existing cells. Schleiden & Schwann

8. Different types of microscopes are used to study cells Light Microscope Most cells Stereo Microscope 1-celled organisms Electron Microscope Cells  small molecules Scanning Electron Microscope 3-D images

9. Two Categories of Cells  Prokaryotes  “Before” nucleus  Simple structure  Bacteria  Archaebacteria  Eukaryotes  True nucleus holds DNA  Many cell parts with special functions  One cell or multicellular organisms  Plants! Animals! People!

10. Hierarchy of organization in complex organisms Tissues and organs have specialized functions

11. Cells have structures specialized for:  Providing a barrier between cell & environment  Storing information for building & maintaining cell(software)  Manufacturing cell parts & machinery  Maintenance  Energy processing  Support, movement & communication

12. All cells have:  Cell membrane  Surrounds, contains, protects  Cytoplasm  “Cell gel” fills interior of cell  Ribosomes  Help make proteins for cells  DNA  Coded instructions for cell (software)

13.  Stop here.  Explore cell parts using GSLC website or Cells Alive

14. Prokaryotic cells may also have:  Cell wall – surrounds cell membrane; protects, maintains shape  Capsule – additional protection; “glue”  Prokaryotic Flagellum – movement  Pili – attach bacteria to surfaces

15. Escherichia coli (E. coli): a simple bacterial cell

16. Helicobacter (causes ulcers)