2. Learning Goals 1. Describe the 3 parts of the Cell Theory and discuss the history behind it. 2. Compare and Contrast a Prokaryotic & Eukaryotic Cell 3. Describe the characteristics of a virus. Is a virus a cell? Is a virus alive?

3. History of Cells

4. The Discovery of the Cell Before microscopes people believed diseases were caused by curses and supernatural spirits People had no idea that bacteria existed Microscopes enabled scientist to view and study cells Cell - the smallest units/building blocks of all living organisms

5. Early Microscopes Robert Hooke –1665 he used a compound light microscope to study cork –He gave these boxed- shaped structures the name “CELL” b/c it reminded him of the small rooms monks lived in ?

6. Spontaneous Generation Vs. BioGenesis Spontaneous Generation= Living things coming from non-living things –Ex. Put a broom in the corner and eventually it will produce mice –Ex. Hay in a barn will produce mice

7. Spontaneous Generation Vs. BioGenesis 1668 – Francesco Redi – Disproved Spontaneous Generation –Meat in jars

8. Spontaneous Generation Vs. Biogenesis Matthias Schleiden 1838 - concluded that all plants are composed of cells Theodore Schwann 1839 - reported that animals are also made of cells Rudolf Virchow 1858 - Developed concept of Biogenesis –Biogenesis = living cells come form other preexisting cells

9. Why Cells are Important What happens inside cells causes us to be who we are. (Genes) All diseases start at the level of the cell. All growth and life starts from a single cell.

10. Cell Theory 1. All living things are made of cells 2. Cells are basic units of life 3. All cells are made from other cells

11. Types of cells 1. Prokaryote2. Eukaryote

12. Prokaryotic Cells (Prokaryotes) Simplest, “primitive” cells with: –NO membrane-bound organelles (“little organs”) –NO nucleus: genetic material floats free in cell pro = before karyo = nucleus

13. Ex: Kingdom Bacteria

14. Eukaryotic Cells (Eukaryotes) Unicellular or multicellular Cells contain: – a nucleus (with DNA) – membrane-bound organelles Eu = truekaryo = nucleus Complex internal structure –“Compartments” allow many different chemical reactions to take place simultaneously

15. Examples: –Kingdom Protista – protozoa, algae, amoeba Kingdom Fungi – mushrooms, molds, yeast

16. Kingdom Plantae (Plants)– ranges from moss to flowering plants Kingdom Animalia (Animals) – ranges from tiny worms to humans

18. What about Viruses? -Are they alive? What do you think? CONS –Cannot grow or replicate without host (dormant) –Are not cells PROS –Have genetic material (DNA or RNA) –Can replicate (with host) –Have a protein coat

19. Viruses In general, not considered living Made of DNA (or RNA) surrounded by a protein coat Are NOT cells & cannot grow

20. Viruses are extremely small!