1. Vocab Word list 11. Passive Transport 12. Active Transport
Know all of these words for the test
Diffusion
Osmosis
Selectively permeable
Equilibrium
Solution
Facilitated Diffusion
Hypertonic
Hypotonic
Isotonic
Contractile Vacuole
11. Passive Transport
12. Active Transport
13. Endocytosis
14. Phagocytosis
15. Pinocytosis
16. Exocytosis
17. Protein Pump

2. Transport Across the Cell Membrane
Fluid Mosaic Model Video clip
Silent video- cell membrane and how it works

3. Cell Membrane Structure
Bi-layer of phospholipids with proteins imbedded
Philic heads = water loving
Phobic tails= water fearing
This helps the cell interact in its aqueous environment. 3

4. FUNCTIONS
1. Gatekeeper
2. Protects and controls the substances going in and out of the cell
3. Selectively permeable - Only certain substances can pass through the membrane.

5. Think …..How does this picture show selective permeability?

6. Think…..How does the gate act like a cell membrane?

7. Things they want to let in: Things they want to let out:
Things they DO NOT want to let in:
The cell tries to let in good things and keep out bad things. Often based on size…small things are allowed in and larger things are kept out or have to be pumped in.
sugar, oxygen, water
carbon dioxide, waste
viruses, bacteria

8. Question 1.
Which statement regarding the functioning of the cell membrane of all organisms is not correct?
The cell membrane forms a boundary that separates the cellular contents from the outside environment.
The cell membrane forms a barrier that keeps all substances that might harm the cell from entering the cell.
The cell membrane controls the movement of molecules into and out of the cell.
The cell membrane is capable of receiving and recognizing chemical signals.

9. Question 2.
In the given diagram of a single-celled organism, that arrows indicate various activities taking place.
Which systems perform these same activities in humans?
Respiratory, nervous and endocrine
Excretory, respiratory, and reproductive
Digestive, circulatory, and immune
Respiratory, excretory, and digestive

10. 4. Recognize and respond to signals by using cell receptors (receptor molecules)
Allows cell to communicate and maintain homeostasis
Are protein molecules on the surface of the membrane with a specific shape.
Advanced video Click on image

11. Protein (cell) Receptor
Cell receptors receive information from chemical messengers (i.e. hormone) by matching up with its shape signaling the target cell to respond and produce a desired product
Insulin
Protein (cell) Receptor
Cell
Membrane

12. Question 3. Cellular communication is illustrated in the diagram below
Information can be sent from
Cell A to Cell B because cell B is able to recognize signal 1
Cell B to Cell A because cell B is able to recognize signal 2
Cell B to Cell A because cell A is able to recognize signal 1
Cell A to Cell B because cell A is able to recognize signal 2

13. Question 4.
Which substance are found on cell surfaces and respond to nerve and hormone signals?
Vitamins and minerals
Subunits of DNA
Receptor molecules
Starches and simple sugars

14. Question 5.
Hormones and secretions of the nervous system are chemical messengers that
Store genetic information
Extract energy from nutrients
Coordinate system interactions
Carry out the circulation of materials

15. Question 6.
In multicelluar organisms, cells must be able to communicate with each other. Structures that enable most cells to communicate with each other are known as
Chloroplasts
Pathogenic agents
Receptor molecules
Antibiotics

16. TYPES OF TRANSPORT http://www.youtube.com/watch?v=kfy92hdaAH0
No energy required
Energy required

17. 1. Passive Transport Requires NO energy
Requires NO energy
Diffusion & Osmosis and Facilitated Diffusion – carrier proteins “help” molecules across the membrane

18. Diffusion
molecules move from an area of high concentration to an area of low concentration
Molecules tend to “spread out”
Requires NO energy
Substances that may diffuse:
Oxygen, carbon dioxide, glucose, amino acids, water
Click on image

19. Equilibrium
When molecules are evenly spread throughout a space

20. Osmosis
Diffusion of water molecules.

21. Cells in different osmotic solutions
Cells behave differently when placed in different solutions!
This is due to OSMOSIS!
Most cells are ~ 98% water!
Three types of osmotic pressure:
Isotonic
Hypotonic
Hypertonic
Watch How osmosis works:

22. Basic Rule for Determining types of Osmostic conditions…..
Salt “SUCKS"
If the area outside the cell has more salt – then water will be “pulled” out of the cell
Watch the animation

23. U - Tubes

24. Isotonic - "ISO" means the same

25. Let’s see….Isotonic Condition
Cell is placed in 98% water
Solution outside of cell has SAME water, same amount of other materials (i.e., salt)
Therefore, solution is equal strength (iso)
Water moves equally;
Equilibrium exists
98%
CELL
STAYS
THE SAME!
98%

26. Hypotonic (Hypo = less)
Water moves in the cell
Cell may burst, or organelles called “contractile vacuoles” remove excess water

27. Let’s see…Hypotonic Condition
Cell is placed in 100% water
Solution outside of cell has MORE water, less of other materials (i.e., salt)
Therefore, solution is below strength (hypo)
100%
Water ENTERS cell
98%
CELL
SWELLS!

28. HYPERTONIC – “Hyper = above”
Water moves out of cell
Cell will shrink (Plasmolysis) or die, plants wilt
Why is it dangerous to drink sea water?
Why does pouring salt on a slug kill it?

29. Let’s see… Hypertonic Condition
Cell is placed in 95% water
Solution outside of cell has LESS water, more of other materials (i.e., salt)
Therefore, solution is above strength (hyper)
Water LEAVES cell
95%
98%
CELL
SHRINKS!

30. Gummy Bear Osmosis Lab

31. Water relations and Cell shape in cells
Animal cell: RBC
Plant Cell
HYPERTONIC
HYPERTONIC
HYPOTONIC
HYPOTONIC

32. Egg Osmosis

33. Facilitated Diffusion
Facilitate- to guide or help.
Protein channels help guide some molecules through the cell membrane.
Watch animation
Let’s see!

34. 2. Active Transport
Watch video:
Movement of molecules from areas of low concentration to areas of high concentration.
Requires ATP (energy).
Against the concentration gradient

35. Active Transport Figure7-20 Active Transport Molecule to be carried
Low
Concentration
Cell
Membrane
High
Concentration
Molecule
being carried
Low
Concentration
Cell
Membrane
High
Concentration
Energy
Energy
Go to Section:

36. Examples of Active Transport :
1. Endocytosis- bring into the cell.
2. Exocytosis- move out of the cell.
endo=within exo=outside cyt=cell osis = process of

37. Endocytosis and Exocytosis

38. Phagocytosis
Cytoplasm extends out and engulfs material to be brought into the cell.
White blood cells and amoeba.
Watch animation:

39. Watch Summary video
Active & passive transport -