1. Unit 3 Movement Through The cell

2. Why is the cell membrane important?
Plasma Membrane/Cell Membrane
Why is the cell membrane important?
Selectively Permeable: A membrane that allows some substances to pass through while keeping others out.
The cell membrane is like a Fish net…lets water in and out, but keeps the fish in

3. Why is the cell membrane important?
Plasma Membrane/Cell Membrane
Why is the cell membrane important?
Cell Membrane: Flexible, selectively permeable boundary that helps control what enters and leaves the cell.

4. What are the 2 main parts of the cell membrane?
Plasma Membrane/Cell Membrane
What are the 2 main parts of the cell membrane?
1. Phospholipid bilayer: 2 layers of lipids (fat)

5. What are the 2 main parts of the cell membrane?
Plasma Membrane/Cell Membrane
What are the 2 main parts of the cell membrane?
2. Protein pump/channel: Proteins that help move large materials across the cell membrane

6. Homeostasis What is homeostasis?
Homeostasis: Regulation of an organism’s internal environment to maintain conditions needed for life.
Running increases body temperature
Panting decreases body temperature

7. Homeostasis What is homeostasis? If you sweat, you lose water….
If you drink water, and replace water levels…
You feel good…
You ARE in homeostasis!
If you sweat, you lose water….
You get dehydrated….
You are not in homeostasis!

8. Homeostasis What is homeostasis? If you have a fever….
You don’t feel good….
You are not in homeostasis!
If you don’t have a fever…
You feel good…
You ARE in homeostasis!

9. Insulin Shots lower sugar levels
Homeostasis
What is homeostasis?
Diabetics can’t regulate sugar levels
Insulin Shots lower sugar levels
If your sugar is too high….
The blood is like syrup…too thick…
Blood can’t flow…you don’t feel good….
You are not in homeostasis!
If your sugar level is normal…
Blood can flow…you feel good…
You ARE back in homeostasis!

10. A cell membrane is like a window screen because:
Clicker Question #1
A cell membrane is like a window screen because:
a. it provides support
b. it prevents water from entering
c. it controls what enters & leaves the cell
d. it prevents everything from leaving

11. b. Phospholipid bilayer c. Carbohydrate pumps d. Protein pumps
Clicker Question #2
These allow larger substances to move into and out of the cell membrane:
a. Lipids
b. Phospholipid bilayer
c. Carbohydrate pumps
d. Protein pumps

12. This is another name for the cell membrane:
Clicker Question #3
This is another name for the cell membrane:
a. Nucleus
b. Phospholipid bilayer
c. Homeostasis
d. Protein pump

13. What is a word that can be associated with “homeostasis”?
Clicker Question #4
What is a word that can be associated with “homeostasis”?
a. Balance
b. Unbalance
c. Fluctuate
d. Unstable

14. Concentration just means how salty the water is
Review….
Solute: Any substance (like salt) that is dissolved in
water is a solute.
Solution: The combination of a solute (salt) and
solvent (water).
Example: salt in water = saltwater
Concentration: Of a solution is the mass of solute in
a given volume of solution.
Concentration just means how salty the water is

15. Nature wants to be balanced!
Remember…
Nature wants to be balanced!
One of the most important functions of the cell membrane is to regulate the movement of molecules from one side of the membrane to the other.

16. Passive Transport
Passive Transport: The movement of molecules from an area of high concentration to an area of low concentration WITHOUT the use of energy.
There are 2 Types of Passive Transport
a. Diffusion
b. Facilitated Transport
The next several slides are about the transport of molecules across the cell membrane that does NOT require ENERGY

17. What are the types of movement through the membrane?
Diffusion is a type of movement of molecules through the cell membrane where the molecules move from an area of HIGHER concentration to an area of LESSER concentration.
Example: Like moving from the city to the country
Higher
Concentration
Lower
Concentration

18. What is Diffusion?
Diffusion causes many substances to move across a cell membrane but does NOT require the cell to use energy.
Diffusion tries to get the solute molecules to be equal on each side of the membrane.
When both sides of the membrane are equal in terms of solute, the cell is in equilibrium.
All cells try to attain equilibrium (BALANCE)!

19. Osmosis & Diffusion
The sound & video does not always match up…you don’t have to point this out!...I know.

20. What are the types of movement through the membrane?
If a substance is able to diffuse across a membrane, the membrane is permeable to that substance.
Example: A sponge is permeable.
Most cell membranes are selectively permeable which means that some substances can pass across easily and others cannot.

21. Lets look at a sugar-water solution.
What is osmosis?
Osmosis is another type of movement across a membrane.
Osmosis is the diffusion of water through a selectively permeable membrane.
Lets look at a sugar-water solution.
One side of the membrane has a concentrated sugar solution and on the other side is a dilute sugar solution.
What type of molecule is sugar?
What does “Macro” mean?
Can sugar easily move across the membrane?
Macromolecule
Large No

22. Water “Chases” the sugar!
What is osmosis?
Sugar cannot move freely across the membrane because it is too big.
The water moves from where there is more water to the area where there is more sugar.
So—in this situation, the water moves from an area of Low concentration of Solute to an area of High concentration of Solute.
Water “Chases” the sugar!

23. What are the 3 types of solutions?
There are 3 types of solutions.
1. Hypertonic
2. Hypotonic
3. Isotonic
Hypotonic
Isotonic
Hypertonic

24. Water is still moving in & out equally!
Isotonic
As you know a cell tries to reach equilibrium. This equal state is also known as an Isotonic solution.
Water is still moving in & out equally!

25. Water “Chases” the solute into the cell
Hypotonic
Example of a Hypotonic solution: Freshwater (no solute)
The cell will have more salt in it and less outside of it.
In a Hypotonic solution, water rushes into the cell causing the cell to expand and eventually burst.
Water “Chases” the solute into the cell
HIGH Concentration
Low Concentration

26. How to Remember!!!!
Hypo = EXPLODE

27. Water “Chases” the solute out of the cell
Hypertonic
Example of a Hypertonic solution: Saltwater
The cell will have less salt in it and MORE outside of it.
In a Hypertonic solution, water rushes out of the cell causing the cell to shrivel and shrink.
Water “Chases” the solute out of the cell

28. How to Remember!!!!
Hyper = shrink

29. Cells in Solutions 5% 5% 5% Hypo = Below Hyper = Above Hypo = Explode
Iso = Same
Hyper = Shrink
15%
.1%
15%
Salt
Salt
.1% 5%
15% 5% 5%
Salt 5%
15%

30. What is facilitated diffusion?
Facilitated Diffusion is a process in which the cell membrane uses the protein channels to allow/help bigger molecules such as ions, sugars, and salts to cross in either direction.
This is still diffusion! No energy is used to move these molecules. The protein channels just “help” the molecules across.
Solute
Cell Membrane
Protein Channel

31. Video 1. The membrane encloses the cell & keeps it _______ inside.
2. Molecules are always on the ______.
3. Molecules move _____ a concentration gradient.
4. Is energy added during passive transport?
5. When the solution is low, the cell will ________.

32. Video

33. Video Questions stable move down Swell & may burst NO Answers
1. The membrane encloses the cell & keeps it _______ inside.
2. Molecules are always on the ______.
3. Molecules move ________ a concentration gradient.
4. Is energy added during passive transport?
5. When the solution is low, the cell will ____________________.
move
down NO
Swell & may burst

34. Active Transport
NEEDS ENERGY!
To High
From Low

35. What type of cellular movement requires energy?
Sometimes, molecules move against the concentration gradient. This means that they are going from a lower area of solute to a higher area of solute. They are crazy!
For this, they need energy to move against the gradient/difference.
Example: Like walking up a hill.
You’ll need ENERGY!
ATP = Energy

36. What type of cellular movement requires energy?
Active Transport uses the protein channels to move these molecules against the gradient with the input of energy.
This is the only movement that requires energy!
This type of transport is often referred to as a pump.

37. Active transport…needs ENERGY!1 2 3
Low concentration of solute
HIGH concentration of solute 1 5 3 4 2

38. Video 1. Moving against the gradient requires _______.
2. Some materials move into & out of cells against their concentration gradient. It is called ________.
3. Active transport is sometimes called a ______.
4. Some large molecules must be absorbed into cells by a process called _________.
5. Think of exo- for ______.

39. Video…a little long….will not see all of it

40. Video Questions Energy Pump Exit
Answers
Energy
1. Moving against the gradient requires _______.
2. Some materials move into & out of cells against their concentration gradient. It is called ___________.
3. Active transport is sometimes called a ______.
4. Some large molecules must be absorbed into cells by a process called ____________.
5. Think of exo- for ______.
Active Transport
Pump
Endocytosis
Exit

41. What are 2 types of Active Transport?
There are 2 types of Active Transport
1. Endocytosis is the process of taking material into the cell by means of in-foldings, or pockets, of the cell membrane.
This pocket, breaks loose from the cell membrane and forms a type of vacuole within the cytoplasm.
Large molecules, like food and other cells can be taken up by endocytosis.

42. Endocytosis

43. 2. Phagocytosis is the process of large particles being taken into the cell by means of extensions of cytoplasm that go out and engulf the large particles.
This is a leukocyte (white blood cell) in
your blood that is shooting out extensions
to get the large particles that you see.

44. 2 Types of Active Transport
2. Exocytosis is the cell’s ability to remove large amounts of materials out of the cell.
During exocytosis, the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell.

45. The End