1. Cell Structures Cell Unit

2. Discovery of Cells   Robert Hooke (1660’s) – –first to observe non-living cells in cork and named them cells   Anton van Leeuwenhoek (1680’s) – –first to observe living cells in lake water and teeth scrapings

3. The Cell Theory   Developed by Schleiden, Schwann, and Virchow (1800’s)   Important points: – –All living things are made of one or more cells. – –Cells are the basic unit of structure and function in living things. – –All cells come from other cells.

4. 2 Basic Types of Cells  Prokaryotes (prokaryotic cells) –Cells that DO NOT have a nucleus –Examples: bacteria  Eukaryotes (eukaryotic cells) –Cells that DO have a nucleus and other organelles –Examples: plant cells and animal cells

5. Cell Structures  Specialized structures that perform specific functions in the cell are called organelles.  Organelle means “little organ”.

6. Cell Wall  Physical Description: a rigid layer of nonliving material that surrounds plant cells  Function: protects and supports the cell  Type of Cell: Found in plant cells  Analogy: Walls of school

7. Cell Membrane  Physical Description: thin, flexible barrier around the cell (just inside the cell wall OR the outside border of animal cells)  Function: controls what enters and leaves the cell  Type of Cell: found in all cells  Analogy: the security system of the school

8. Nucleus  Physical Description: large organelle that is usually near the center  Function: controls the cells activities  Type of Cell: found in all eukaryotes  Analogy: the office of a school

9. Nuclear Envelope (Membrane)  Physical Description: Small spherical structure within the nucleus that holds in strands of genetic material (DNA)  Function: Hold in genetic instructions for the cell to do its job  Type of Cell: found in all eukaryotic cells  Analogy: the walls of the office

10. Chromatin  Physical Description: Thin strands of genetic material  Function: The genetic instruction for the cell to do it’s job  Type of Cell: found in both eukaryotic and prokaryotic cells  Analogy: the principal him/herself

11. Nucleolus  Physical Description: Small dark structure within the nucleus  Function: Create ribosomes  Type of Cell: found in all eukaryotic cells  Analogy: the substitute teacher

12. Cytoplasm  Physical Description: the fluid-like material inside the cell membrane  Function: contains the organelles; “cell jelly” and is a site for chemical reactions  Type of Cell: found in all cells  Analogy: the air inside the school

13. Mitochondria  Physical Description: “bean-shaped” organelle that has a folded inner membrane  Function: breaks down FOOD to release energy for use by the cell  Type of Cell: found in all eukaryotes  Analogy: the boiler and generator of the school

14. Endoplasmic Reticulum (ER)  Physical Description: internal membrane system –Rough - has ribosomes –Smooth- no ribosomes  Function: assembles parts of cell membrane and modifies proteins  Type of Cell: found in all eukaryotes  Analogy: the copy room of a school

15. Ribosomes  Physical Description: tiny, round structures either attached to the ER or floating in cytoplasm  Function: makes proteins  Type of Cell: found in all eukaryotes AND some prokaryotes  Analogy: the teachers in a school

16. Golgi Apparatus (aka Golgi Body)  Physical Description: stack of membranes in the cytoplasm  Function: receives proteins and other materials from ER; gives proteins the “address” of their final destination  Type of Cell: found in all eukaryotes  Analogy: the busses of a school

17. Chloroplast  Physical Description: tubular organelle that contains chlorophyll (a green pigment)  Function: use energy from SUNLIGHT to MAKE FOOD through photosynthesis  Type of Cell: found in many plant cells  Analogy: the solar energy panels of a school

18. Vacuole  Physical Description: large, spacious sack in the cytoplasm  Function: stores materials for the cell (water, food, waste, etc…)  Type of Cell: found in all eukaryotes (usually one large vacuole in plants and many small vacuoles in animals)  Analogy: the storage closet of a school

19. Lysosome  Physical Description: small, round sacks in the cytoplasm  Function: breaks down large food particles and old or damaged organelles  Type of Cell: found in all eukaryotes BUT are very rare in plant cells  Analogy: the janitor of a school

20. Plant Cells vs. Animal Cells  Cell Wall  Chloroplasts  Lysosomes are rare  1 Large Vacuole  No Cell Wall  No Chloroplasts  Lysosomes are common  Several Small Vacuoles

21. Job of Cells  The main job of all cells is to make proteins  Different cells make different types of proteins for different functions  Steps of protein production: 1)Ribosome 2)Endoplasmic Reticulum 3)Golgi Apparatus 4)Final Destination of the Protein (may be outside of the cell)