1. Bell Work:
Draw a phospholipid bilayer (double layer of phospholipids) and arrange the tails on the inside

2. Bell Work Pick up: Notes page on front table Have out:
Cell membrane color sheet in your notebook
Homework Assignment Notice:
Membrane color sheet = due today
Edpuzzle Membrane Transport video = due by tonight at midnight
Edpuzzle Osmosis video = due by Thursday night at midnight

3. Quiz in just a few minutes
Bell Work
Have out and be studying:
Your cell transport notes page AND your POGIL from yesterday
Quiz in just a few minutes

4. Phenomena

5. Membrane Structure and Cell Transport
Chapter 5

6. Objectives:
CLE Compare different models to explain the movement of materials into and out of the cell.
SPI Compare active and passive transport.
RLE Recognize the importance of homeostasis as a survival mechanism.

7. Choose with your shoulder partner:

8. Homeostasis Define homeostasis: Macro example: Micro example:
Maintaining a stable internal balance
We maintain a stable body temperature.
Cells use the cell membrane to regulate what comes in and out of the cell to keep steady levels of nutrients, water and other substances.

9. Cell Membrane - Function
All cells have a cell membrane
Functions:
Controls what enters and exits the cell (to maintain the internal balance called homeostasis)
Provides protection and support for the cell

10. Cell Membrane - Structure
Structure of cell membrane
Lipid Bilayer -2 layers of phospholipids
Phosphate head is polar (water loving)
Fatty acid tails non-polar (water fearing)
Proteins embedded in membrane

12. Semi – Permeable (Selectively Permeable)
allows certain molecules or substances to pass through it
Keeps other molecules out
The structure helps it be selective!

13. Frogs
Explain to your lizard what semi-permeable means

14. Demonstration Cornstarch
Plastic bag (represents a cell with a semi-permeable membrane)
Beaker w/ water and Lugols Iodine
Prediction:
Will Iodine be allowed to pass through the membrane? How will we know?
Will starch pass through the membrane? How will we know?

15. Cell Transport Passive Transport Active Transport Diffusion Osmosis
Facilitated Diffusion
Does NOT require energy, moves from HIGH concentrations to LOW concentrations
DOES require energy, moves from LOW concentrations to HIGH concentrations, moves LARGE molecules (glucose) via transport proteins
Moves small molecules, like CO2 & O2 gases, directly through the membrane
Movement of water across the membrane
Uses transport proteins to move large molecules through the membrane WITHOUT energy
3 Types of Solutions
Hypertonic
Isotonic
Hypotonic
Water moves out of the cell & it shrinks
Water moves into the cell & it swells
Water moves equally in and out of the cell; it stays the same size
Protein Pumps
Endocytosis
Exocytosis
Transport proteins that require energy to do work. Example: Sodium / Potassium Pumps are important in nerve responses.
Materials ENTER the cell through a vesicle formed by the membrane
Materials EXIT the cell through a vesicle formed by the Golgi Body
Controlled via the Cell Membrane

16. Cell Membrane Transport
Two main types of cell transport:
Passive:
Active:
high
low
Weeee!!!
the movement of substances across the cell membrane without energy.
the movement of substances across the cell membrane with the use of energy.
high
low
This will be hard work!!

17. Lizards:
Explain to your frogs the difference between passive and active transport

18. Types of Passive Transport (No energy) (High to Low)
Diffusion
Osmosis
Facilitated Diffusion
Movement of SOLUTES (small molecules)
Movement of WATER molecules
Diffusion of large or polar molecules using protein channels or pores

19. Concentration Concentration:
Two parts needed to determine concentration:
Solvent:
Solute:
The amount of a substance in a given volume
The substance with the greatest volume
What the solute is dissolved in.
The substance with the smaller volume
The substance(s) that are dissolved in the solvent.

20. Solute vs Solvent
Example: Salt water
Solvent?
Solute?
Water
Salt

21. Example: Food coloring in water
Solute and Solvent
Example: Food coloring in water

22. Concentration Gradient

23. Passive Transport = High to Low
Why will things move from high concentration to low concentration?
All molecules are moving.
As they bump into each other they move faster until there is even space between them.

24. Passive Transport Leads to Equilibrium
When the concentration of molecules is the same throughout the space the molecules occupy.

25. Frogs:
Explain why molecules want to move from areas of high concentration to low

26. How does this affect cells?
Diffusion:
Osmosis:
Remember: All passive transport moves from high to low concentration trying to create an equilibrium
Lungs: can send CO2 out of the red blood cells and get O2 in
Cells: can get O2 into them and send out CO2
When cells need more water to perform hydrolysis, can pull water in from the blood.
If cells need to remove water that built up after many sets of c
tondensation, they can send water out to blood

27. Facilitated Diffusion (Passive)
Definition:
Video - "Facilitated Diffusion”
Diffusion of molecules unable to get across membrane by going through the phospholipid layer
Require use of carrier protein channels
Examples: Glucose (too large), Na+ (has a charge)

28. Facilitated Diffusion (Passive)
Some molecules are too big to enter the cell without help

29. Demonstration Check:
Record the results of the corn starch in iodine experiment.
Did iodine enter the cell? How do you know?
Did starch exit the cell? How do you know?

30. Passive Transport Review:
Three types:
Diffusion:
Osmosis:
Facilitated diffusion:
Common Characteristics:
Don't use any energy
Move from high to low concentration
small solutes (O2 or CO2) moving across the membrane
movement of water across the membrane
larger solutes (glucose) moving across the membrane through channels or pores

31. Lizards:
Summarize the 3 types of passive transport to your frog

32. Exit Ticket
Differentiate between diffusion and facilitated diffusion?