1. BELL RINGER
What part of the cell controls the materials that enter and exit the cell? What type of biomolecule is this structure made out of?

2. Movement Through a Membrane Video

3. HOMEOSTASIS REACP VIDEO (3)
Answer the first 4 questions on your unit 6 notes while watching the short 3 min recap/review/intro video.

4. Cell Membrane
Function: Regulates what enters and leaves the cell and provides support.
Made of:
phospholipid: Support/Structure
Proteins: Act as channels and pumps
Carbohydrates: Act like ID cards.
Selectively Permeable: some substances can pass across and others cannot.

5. Phospholipid Bilayer Outside of cell Water Inside of cell Water
membrane
Proteins
Protein
channel
Lipid bilayer
Carbohydrate
chains
Inside of cell
Water

6. Phospholipid
Polar Head
Hydrophilic
Non polar Tail
Hydrophobic

7. Diffusion
Diffusion: movement of molecules from high to low concentration directly across the membrane
Simple Diffusion
Passive Transport: Does not require energy
Molecules move with the concentration gradient
Molecules continue until they reach equilibrium (equal concentrations on both sides of the membrane).

9. Concentration Gradient
Movement from high concentration to low concentration

10. Facilitated Diffusion
Facilitated Diffusion: protein channels help some LARGE molecules diffuse across the membrane.
Large molecules are unable to cross the cell membrane. Protein channels are specific for large molecules.
Only occurs if there is a concentration gradient.
Does not require energy.

11. Facilitated Diffusion
Glucose
molecules
High
Concentration
Cell
Membrane
Protein
channel
Low
Concentration

12. Video Recap

13. HIGH LOW

14. Concentration Gradient
High
Concentration
Molecules moving from high concentrations to low
Low
Concentration

15. Bell Ringer What is diffusion?
Diffusion is movement of molecules across a membrane.
What is a concentration gradient?
Concentration gradient is movement of molecules from high concentration to low concentration.
What are two ways that molecules can get into a cell?
Two ways that molecules can get into a cell are diffusion and facilitated transport.

16. POTATO LAB!! What will keep potatoes fresh and why?
Understand how cells maintain homeostasis through cell transport.

17. Bell Ringer How do small molecules move across the membrane?
In your potato lab what was causing the potatoes to lose “freshness”.
How are potato cells similar to human cells?

18. Osmosis VIDEO (10)
Osmosis: diffusion of water through a selectively permeable membrane from high to low concentration.
Isotonic: same amount of water and solute on both sides
Hypotonic: less solute side
Hypertonic: more solute side
Example of a solute in a solution would be SALT in saltwater. Salt is a SOLUTE remember solutes SUCK!

19. Osmosis Cell membrane Water molecules Higher Concentration of Water
Lower Concentration
of Water
Sugar molecules

20. SAME
SAME
Swell
Swell
Shrink
Shrink

22. Question: What kind of solution is salt water compared to a cell?
Hypertonic because it has a higher salt concentration compared to a cell.
Question: What happens to a cell if we put it in salt water?
Water will leave the cell by osmosis causing the cell to shrink.
Hypotonic Hypertonic Isotonic

23. Osmosis
The video clip explains you can also think of water as moving to a _______ concentration of solute molecules
Why can it also be viewed this way?
Solutes suck water towards them
Higher

24. Fish Hypertonic- Water moves out of the fish and fish shrinks SAVE ME!
Hypo

25. Brain swelling treatment- adding a hypertonic saline
Explain ….

26. Active Transport LOW TO HIGH
Active Transport: the movement of molecules against the concentration gradient (uphill).
Requires energy (ATP)
Often compared to a pump
Example: The Sodium (Na+) Potassium (K+) Pump in the cell membrane pumps sodium out of the cell and potassium into the cell.
AGAINST

27. Concentration Gradient
High
Concentration
Molecules moving from low concentrations to high
Energy
Low
Concentration

28. Active Transport
Molecule to
be carried
Low
Concentration
Cell
Membrane
High
Concentration
Molecule
being carried
Low
Concentration
Cell
Membrane
High
Concentration
ATP
Energy

30. Movement Direction:
Endocytosis: (enter) particles are taken into the cell
Exocytosis: (exit) particles are removed from the cell

31. Bell ringer How does water move across the membrane?
What is an isotonic solution?
What is a hypotonic solution?
What will happen if a blood cell is placed into a hypertonic solution?
Amoeba sisters video review

32. Bell Ringer Define Osmosis: Diffusion: Active transport:
Passive transport:
Semipermeable:
movement of water across a membrane towards the area of higher solute concentration.
Movement of molecules from high to low concentration
Movement of molecule from low to high concentration using energy
Movement of molecule from high to low concentration without using energy
Some molecules can pass through while others cannot

33. Bell Ringer Hydrophilic: Hydrophobic: Solute: Isotonic: Hypertonic:
Hypotonic:
Equilibrium:
Water loving, polar head of phospholipid
Water hating, non-polar tail of phospholipid
Substance that sucks water towards it in solution, Sugar or salt
Equal amount of solute and water
Side with more solute
Side with less solute
Amount of all molecules on both sides of membrane are equal

35. Bell Ringer: What are cell membranes made of?
What happens to a cell if it is placed in salt water?
What is the function of the ribosome?
Where does aerobic respiration take place in plant and animal cells?
Which organelle controls the cell?
What is the term for water moving through a membrane?
How does oxygen pass into or out of a cell?

36. Bell Ringer:
If a molecule is moving down the concentration gradient, is it going from high concentration to low concentration or low to high concentration?
Does diffusion require energy?
What will happen to a cell if you put it in a hypertonic solution?
Molecules continue to move down the gradient until they reach what?
Draw and label a cell membrane.

37. Bell Ringer: What are the 3 parts of Cell Theory?
Which organelle is the Control Center of the cell?
Which organelle controls the passage of materials in and out of the cell?
Which organelle is where proteins are made?
What are 2 organelles that are in plant cells and not animal cells?
What is the main difference between a prokaryotic and a eukaryotic cell?

38. Joke of the Day: