1. Objectives
List scientists who contributed to the cell theory
List the components of the cell theory
Compare prokaryote and eukaryote cells
Label a plant and an animal cell
Know the functions of cell organelles

2. Early Contributions
Robert Hooke - First person to see cells, he was looking at cork and noted that he saw "a great many boxes. (1665)
Anton van Leeuwenhoek - Observed living cells in pond water, which he called "animalcules" (1673)

3. Theodore Schwann - zoologist who observed tissues of animals had cells (1839)
Mattias Schleiden - botanist, observed tissues of plants contained cells ( 1845)
Rudolf Virchow - also reported that every living thing is made of up vital units, known as cells. He predicted that cells come from other cells. (1850 )

4. The Cell Theory 1. Every living organism is made of one or more cells.
2. The cell is the basic unit of structure and function. It is the smallest unit that can perform life functions.
3. All cells arise from pre-existing cells.
*Why is the Cell Theory called a Theory and not a Fact?

5. Cell Features ALL cell have these parts
Ribosomes – make protein for use by the organism
Cytoplasm – fluid material within  cell
DNA – genetic material
Cytoskeleton – internal framework of cell
Cell Membrane – outer boundary, some things can cross the cell membrane

6. Comprehension Checkpoint
Answer true or false
Robert Hooke was the first person to see cells.
Bacteria cells have a cell membrane.
The Cell Theory was developed by a single scientist.
Plant cells have cytoplasm.
Cells taken from fungi do not have DNA.
Cells can only come from pre-existing cells.
It only took five years to develop the Cell Theory.

7. Prokaryote Cells The first cells to inhabit the earth Simple cells
Bacteria
These cells do NOT have a nucleus, their DNA is circular and floats in the cytoplasm
Some bacteria have a tail-like structure called a flagella, that helps it to move.
A capsule surrounds some bacteria and helps them avoid the body’s immune system

8. Bacteria Images
Bacteria that causes Anthrax

9. Eukaryotic Cells Cells found in plants, animals, protists, and fungi
The cell is composed of 4 main parts:
Cell membrane
Cytoplasm
Nucleus – “control center” of cell, houses DNA
Organelles – small structures that carry out specific functions (“little organs”)

10. Nucleus Usually found at center of cell
Has a nuclear membrane & nuclear pores
 Contains cell’s DNA in one of 2 forms
chromatin - DNA bound to protein (non-dividing cell)
chromosomes - condesed structures seen in dividing cell
 Also contains an organelle called nucleolus - which makes the cell’s ribosomes

11. Cell Organelles
Mitochondria – this is the cell’s energy center. It turns food into a chemical energy called ATP
The mitochondria is sometimes called the “powerhouse” of the cell

12. Cell Organelles
Golgi Apparatus – processes, packages and secretes proteins. It is comparable to a factory or a post office.
*A vesicle forms with Golgi to transport substances outside cell.  

13. Cell Organelles
Lysosome – Contains digestive enzymes, breaks things down, "suicide sac”
Endoplasmic Reticulum – Transport, "intracellular highway".
 -Rough ER contains many ribosomes & is involves in protein synthesis
 -Smooth ER ribosomes not found on surface

14. Cell Organelles Cytoskeleton – Helps cell maintain
support & shape; movement
a. microtubules-hollow structures; also
help build cilia  flagella
b.  microfilaments-threadlike
c.  centrioloes-only in animal cells; used during cell division (paired) 
Vacuole – storage area for water and other substaces, plant cells usually have a large central vacuole

15. Protein Production
The cell is like a factory. Its product is protein which goes to body to serve different functions.
DNA has instructions to build protein
These instructions are sent to ribosomes
The ribosomes build protein and send it through ER
The proteins are delivered to golgi where they are completed and “tagged” for export outside cell

16. THE ANIMAL CELL

17. Cheek Cells Seen Through Microscope

18. Plant Cells Have additional structures
CELL WALL – surrounds membrane & provides additional support
CHLOROPLASTS – contain green pigment, function in photosynthesis
CENTRAL VACUOLE – large water container in center of cell

19. PLANT CELL
Can you identify the parts?

20. Anacharis Cells Viewed With a Microscope

21. Organelles With DNA
Mitochondria and chloroplasts have their own DNA (separate from the nucleus)
This supports the ENDOSYMBIOSIS THEORY which states that eukaryotic cells evolved when prokaryote cells engulfed or absorbed other cells.

22. CELL MEMBRANE
Selectively permeable ; it regulates what comes into the cell and what leaves the cell
It is composed of a double layer of phospholipids with proteins embedded throughout