1. THE CELL

2. Definition of Cell A cell is the smallest unit that is capable of performing life functions.

3. Cell Theory 1. All organisms are composed of cells 2. Cells are the basic units of structure and function in organisms 3. All cells come from preexisting cells

4. Two types of cells  Prokaryotic Pro / karyote Before / nucleus (Greek) Prokaryotes: more primitive cells that lack a true nucleus.  Eukaryotic Eu / karyote True / nucleus Eukaryotes: cells that have a true membrane bound nucleus that contains the DNA

5. Prokaryotic cells  Two domains in living world: Archaea and Bacteria

6. These are prokaryote E. coli bacteria on the head of a steel pin. Bacteria For the first half of geological time our ancestors were bacteria. Most creatures still are bacteria, and each one of our trillions of cells is a colony of bacteria. Richard Dawkins

7. Archaea Not discovered until late 1970s Once thought to inhabit only extreme environments: hot springs, deep sea trenches, under the earth, salt flats (extremophiles) but now known to live everywhere Leading scientists to rethink how life arose in early days of Earth

8. Prokaryotic Cell Capsule – slimy outer surface present only in some bacteria Cell wall – protects cell and gives it shape Plasma membrane – regulates movement of materials in and out of cell Flagellum – allows cell to move Pili – allows cell to stick to surfaces Very small:.1-10 microns

9. Prokaryotic Cell Cytoplasm – gel-like liquid that contains parts that do work of the cell Ribosomes – build proteins DNA – hereditary material sits loose in the cell, is not organized in chromosomes

10. Prokaryotes play a huge role in our lives  Yes, harmful diseases TB Rod shaped cells (bacilli) Strep throat Circular shaped cells (cocci) Lyme disease Spiral shaped cells (spirochete)

11. But life wouldn’t exist as we know it without them  Cyanobacteria: their ability to photosynthesize created the oxygen-rich atmosphere that exists today

12. Digestion – E coli in our intestines helps us break down food to get the nutrients we need

13. Decomposers: recycle nutrients Example: nitrogen-fixing bacteria: help plants that we eat obtain enough nitrogen to grow

14. Biotechnology: solutions for major problems  Example: environmental clean-up

15. Example: Faster growing, disease resistant, more nutritious food

16. Example: Cure diseases

17. Eukaryotes Includes 4 kingdoms: Protists Fungi Plants Animals (including us)

18. Eukaryotes vs. Prokaryotes Big differences:  Have a membrane-bound nucleus that encloses the DNA*  DNA is organized as chromosomes  Have other membrane-bound organelles to carry out cell life processes  Much larger (10-100 microns)  Specialize to form multicellular organisms

20. Advantages of each kind of cell architecture ProkaryotesEukaryotes simple and easy to growcan specialize fast reproductionmulticellularity can live in many different environments can build large bodies

21. http://videos.howstuffworks.com/discovery/2873 2-assignment-discovery-elements-of-cells- video.htm

22. Vocabulary Be able to define/explain these Cell Theory Prokaryote Eukaryote Bacteria Archaea Extremophile Unicellular Multicellular Nucleus Flagellum Pili Cytoplasm Ribosomes Membrane