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: Thin membrane that surrounds the nucleus that allows materials to pass in and out through tiny holes.
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:
Ribosome
Endoplasmic Reticulum
Golgi Apparatus
Final Destination of the Protein (may be outside of the cell)