1. Topic 3: The Incredible Cell

2. What is a cell? Very smallest unit of living matter
Are building blocks
Cells work together to build more complicated organisms

3. Cell theory 1. Cell is the basic unit of life
2. All living organisms are composed of cells
3. Cells come from pre-existing cells
4. Heredity information is passed on from cell to cell
5. All cells have the same basic chemical composition
6. Energy flow occurs within cells

4. A Cell’s Internal Structures
Organelles
Internal structures that perform specific functions
8 common organelles to ALL cells

5. 1. Cell membrane
Thin layer that surrounds the cell
Keeps all of the other organelles inside
Gateway
Allows required materials in and wastes out
Selectively permeable
Only some materials move in and out

6. 2. Cytoplasm
Medium (substance) that holds the organelles in place
Contains water, minerals, vitamins, salts, and other chemicals
‘Kitchen’ of the cell
Where all of the reactions happen

7. 3. Nucleus
Command center of the cell
Directs all activities that occur within the cell
Contains DNA
Serves as a blueprint

8. 4. Mitochondria
Powerhouse of the cell
Produces energy
Site where sugar is converted into a usable form called ATP

9. 5. Vacuole
Storage room for nutrients, water and other materials

10. 6. Endoplasmic reticulum (ER)
Network of folded membranes
2 jobs:
Produces proteins, lipids (fats), steroids
Acts as an assembly and packaging system

11. 7. Golgi apparatus
Network of folded membranes & bubble-like vesicles
Packaging and transport system

12. 8. Lysosomes
2 jobs:
Digestion machines
Garbage disposal
Contains enzymes that digest (break down) materials

13. Type specific organelles
Animal cells
Have the 8 organelles common to all cells
Vacuoles are small
Generally circular in shape

14. Plant cells
Vacuoles are large
If little water is stored, plant is limp
If lots of water is stored, plant is rigid

15. Have the 8 organelles common to all cells + 2 additional organelles
9. Cell wall
Frame of the cell (outside the membrane)
Provides strength and support
10. Chloroplast
“Solar panel” of the cells
Collects sunlight
Where photosynthesis occurs
Contain chlorophyll (green pigment)

16. Movement of Substances in Cells

17. All cells need to take in materials & get rid of wastes
It is the cell membrane that allows this happen
Tiny openings that allow SOME particles (eg. oxygen, water) are allowed to pass through
Cell membrane = selectively permeable

18. Diffusion
Movement of particles from an area of high concentration to an area of low concentration
Continues until the concentration of particles is the same everywhere

19. Osmosis Diffusion of water
The amount of water inside the cell must stay approximately the same as the amount outside
Why?

20. Cells & Organisms Unicellular Made of only a single cell Amoeba
Paramecium

21. Advantages of being unicellular?
Disadvantages of being unicellular?

22. Multicellular
Made of 2 or more cells
Cells are specialized
Each cell type performs a specific job
Cells within the organism interact with one another

23. Advantages of being multicellular?
Disadvantages of being multicellular?