1. Cell Structure & Transport
Unit 5
Cell Structure & Transport

2. Cell Theory
All living things are composed of cells
Cells are the basic unit of structure and function in living things
New cells are produced from pre-existing cells

3. Cells come in many shapes and sizes!
Specialized Cells
bone cells
skin cells
3.blood cells
4.nerve cells

4. Some organism are made up of only ONE cell !!
Uni-cellular Organisms
E. coli bacteria
Amoeba
Paramecium

5. Biologist divide cells into two categories: Prokaryotes and Eukaryotes
Small & Simple
Mostly found in large organisms.
Cell Membranes
Cytoplasm
Cytoplasm & Specialized Structures
NO Nucleus
Nucleus

6. Description & Function
Cell Structures
Name
Description & Function
Image
1. Cell
Membrane
A thin flexible barrier around a cell that regulates what enters and leaves the cell.

7. Description & Function
Name
Description & Function
Image 2.
Cell Wall
Only found in plant cells. Offers protection and rigidity to all plant cells.

8. Description & Function
Name
Description & Function
Image 3.
Nucleus
Controls most cell processes and contains the hereditary information found on the DNA

9. Description & Function
Name
Description & Function
Image 4.
Cytoplasm
The material inside the cell membrane. It offers support to all the other cell structures in the cell.

10. Description & Function
Name
Description & Function
Image 5.
Ribosome
Small particles in the cell on which proteins are assembled.

11. Description & Function
Name
Description & Function
Image 6.
Endoplasmic Reticulum
Components of the cell membrane are assembled here.

12. Description & Function
Name
Description & Function
Image 7.
Golgi
Apparatus
The place where enzymes attach carbohydrates and lipids to proteins.

13. Description & Function
Name
Description & Function
Image
8. Lysosomes
Filled with enzymes and breaks down lipids, carbohydrates, and proteins. Animal cell only

14. Description & Function
Name
Description & Function
Image 9.
Vacuoles
Store materials like water, and salts

15. Description & Function
Name
Description & Function
Image
10.
Chloroplasts
Found only in plants. The site of photo-synthesis

16. Description & Function
Name
Description & Function
Image
11.
Mitochondria
Releases the energy stored in glucose molecules.

17. Generalized
Animal Cell

18. Generalized Plant Cell

19. Movement through the Membrane
The membrane is important because it separates the cell from its surroundings.
It regulates what enters and leaves the cell and also provides protection and support.
Membrane Design:
It is a called a lipid bi-layer which is actually a double layer membrane made up of proteins and lipid molecules.

20. Cell membrane Outside of cell Carbohydrate chains Proteins Cell
Inside
(cytoplasm)
Cell
membrane
Proteins
Protein
channel
Lipid bi-layer
Carbohydrate
chains
Cell membrane

21. Moving Materials Across the Cell Membrane
Molecules DO NOT just cross into or out of a cell randomly.
Two factors determine if a molecule will cross the membrane.
Size of the molecule
Concentration of the molecules on one side of the membrane as compared to the concentration on the other side of the membrane

22. Passive Transport
The movement of materials across the membrane without the cell needing to expend any energy to make it happen.
Three different types:
Diffusion
Facilitated Diffusion
Osmosis

23. Diffusion
Molecules move from a region of high concentration to a region of lower concentration.
high to low is the easy way to go

24. Facilitated Diffusion
Movement of larger molecules across cell membranes through transport protein channels.
Glucose
molecules
High
Concentration
Cell
Membrane
Low
Concentration
Protein
channel

25. Osmosis 1.It is the diffusion of water molecules across the membrane.
2.Sometimes molecules are simply too big to move across the membrane. In these cases Water will move across the membrane so that a balanced concentration can be reached.
(This is called equilibrium)

26. What is Tonicity?
Tonicity is a measure of the water pressure inside of a cell as compared to the water pressure outside of the cell.
Tonicity is influenced only by substances that cannot cross the membrane.
Substances able to freely cross the membrane do not affect tonicity because they will always be in equal concentrations on both sides of the membrane.

27. Isotonic Solution
Plant Cell
The size of the cell remains the same!

28. Isotonic Animal Cell

29. Hypotonic Solution
Plant Cell
The size of the cell increases!

30. Hypotonic Animal Cell

31. Hypertonic Solution
Plant Cell
The Size of the cell decreases!

32. Hypertonic Animal Cell

33. Active Transport
The movement of materials from an area of lower concentration to an area of greater concentration.
It requires a special energy from the cell known as ATP energy.
Movment is against the concentration gradient.(Think of it as trying to swim upstream agaisnt the current!!!!)

34. Molecule being carried
Active Transport of molecules against a concentration gradient requires the use of transport proteins in the cell membrane and ATP energy from the cell.
Molecule to be carried
Low Concentration
Cell membrane
High Concentration
Energy
Molecule being carried
Low Concentration
Cell membrane
High Concentration