1. Chapter 8 – Cellular Transport

2. Plasma Membrane
Selectively permeable
Controls what passes through the membrane
Made of: phospholipids, proteins, and cholesterol.

3. Diffusion
Movement of molecules from a high concentration of molecules to a low concentration of molecules
Brownian movement: molecules are moving all the time-
(random movement)

4. Concentration Gradient
Difference in the concentration of molecules across a space
Molecules will move until the solute and solvent are mixed evenly

5. Dynamic Equilibrium
When the concentration of the molecules are equally distributed
There is no concentration gradient
There will still be movement of particles, but no net change

6. Osmosis
Diffusion of water molecules through a selectively permeable membrane (type of diffusion)
High concentration to…..
Low concentration

7. Osmosis: Diffusion of Water
Regulating the water flow through the plasma membrane is an important factor in maintaining homeostasis within a cell.

8. Section 8.1 Summary – pages 195 - 200
What controls osmosis?
Unequal distribution of particles, called a concentration gradient, is one factor that controls osmosis.
Before
Osmosis
After
Osmosis
Water molecule
Sugar molecule
Selectively permeable membrane
Section 8.1 Summary – pages

9. 3 type of solutions Isotonic Solution Hypertonic Solution
Hypotonic Solution

10. Section 8.1 Summary – pages 195 - 200
Cells in an isotonic solution
In an isotonic solution, the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell.
H2O
H2O
Water Molecule
Dissolved Molecule
Section 8.1 Summary – pages

11. This means:
The concentration of the water is the same inside the cell and outside the cell
Dynamic Equilibrium has been reached

12. Cells in an isotonic solution
In an isotonic solution, water molecules move into and out of the cell at the same rate, and cells retain their normal shape.
H2O
H2O
Water Molecule
Dissolved Molecule

13. Section 8.1 Summary – pages 195 - 200
Cells in an isotonic solution
A plant cell has its normal shape and pressure in an isotonic solution.
Section 8.1 Summary – pages

14. Cells in a hypertonic solution
In a hypertonic solution, there is a higher concentration of dissolved substances (solute) in the solution than the concentration inside the cell

15. The water concentration is lower outside the cell than inside the cell
This means…….
The water concentration is lower outside the cell than inside the cell

16. Section 8.1 Summary – pages 195 - 200
Cells in a hypertonic solution
In a hypertonic solution, water leaves a cell by osmosis, causing the cell to shrink.
H2O
H2O
Water Molecule
Dissolved Molecule
Section 8.1 Summary – pages

17. Cells in a hypertonic solution
Plant cells lose pressure as the plasma membrane shrinks away from the cell wall.

18. Cells in a hypotonic solution
In a hypotonic solution, there is a lower concentration of dissolved substances (solute) in the solution than inside the cell

19. Water concentration is higher outside the cell than inside the cell
This means…..
Water concentration is higher outside the cell than inside the cell

20. Cells in a hypotonic solution
In a hypotonic solution, water enters a cell by osmosis, causing the cell to swell.
H2O
H2O
Water Molecule
Dissolved Molecule

21. Section 8.1 Summary – pages 195 - 200
Cells in a hypotonic solution
Plant cells swell beyond their normal size as pressure increases.
Section 8.1 Summary – pages

22. Blood cell
Plant cell

23. Review Hypotonic solution-hippo/hypo Water enters his mouth- looks
like he is going to explode

24. Review
Hyper kids rushing out of class after 2 hours in 104 degree classroom
Hyper-Hypertonic- water leaves the cell

25. Types of Transport
Passive Transport
Active Transport

26. Passive Transport Movement of particles across membranes by diffusion
- the cell uses NO energy to move the
particles
- particles move ALONG the
concentration gradient

27. Passive Transport High Concentration to Low Concentration Diffusion
Facilitated Diffusion
Osmosis
High Concentration to Low Concentration

28. Facilitated Diffusion
Type of passive transport that uses transport proteins
Doesn’t use energy

29. Active Transport Transport that requires energy
Transport of materials AGAINST the concentration gradient
High Concentration
Low Concentration

30. Active Transport
Endocytosis
Exocytosis

31. Endocytosis
Phagocytosis- cell engulfs particle with pseudopodia (cell eating)
Pinocytosis-cell gulps/drinks extracellular fluid (cell drinking)

32. Section 8.1 Summary – pages 195 - 200
Transport of Large Particles
Endocytosis is a process by which a cell surrounds and takes in material from its environment.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Section 8.1 Summary – pages

33. Section 8.1 Summary – pages 195 - 200
Transport of Large Particles
The material is engulfed and enclosed by a portion of the cell’s plasma membrane.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Section 8.1 Summary – pages

34. Section 8.1 Summary – pages 195 - 200
Transport of Large Particles
The resulting vacuole with its contents moves to the inside of the cell.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Section 8.1 Summary – pages

35. Section 8.1 Summary – pages 195 - 200
Transport of Large Particles
Exocytosis is the expulsion or secretion of materials from a cell.
Nucleus
Wastes
Digestion
Exocytosis
Endocytosis
Section 8.1 Summary – pages

36. Transport of Large Particles
Endocytosis and exocytosis both move masses of material and both require energy.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis

37. Question 1 A. active transport
The diffusion of water across a selectively permeable membrane is called __________.
Water molecule
Selectively permeable membrane
Sugar molecule
A. active transport
B. endocytosis
Section 1 Check

38. Question 1
The diffusion of water across a selectively permeable membrane is called __________.
Water molecule
Selectively permeable membrane
Sugar molecule
C. exocytosis
D. osmosis
Section 1 Check

39. The answer is D, osmosis. Regulating the water flow through the plasma membrane is an important factor in maintaining homeostasis within the cell.
Before osmosis
After osmosis
Water molecule
Selectively permeable membrane
Sugar molecule
Section 1 Check

40. Question 2
What is the expected result of having an animal cell in a hypertonic solution?
A. The cell shrivels up.
B. The plasma membrane shrinks away from
the cell wall.
C. The cell swells up.
D. The cell retains its normal shape.
Section 1 Check

41. The answer is A. In a hypertonic solution, cells experience osmosis of water out of the cell. Animal cells shrivel because of decreased pressure in the cells.
H2O
H2O
Water molecule
Sugar molecule
Section 1 Check

42. Question 3
A grocer mists the celery display with water to keep it looking fresh. What type of solution is the celery now in?
A. isotonic
B. hypotonic
C. hypertonic
D. exotonic
Section 1 Check

43. The answer is B. Plant cells contain a rigid cell wall and do not burst even in a hypotonic solution.
Section 1 Check

44. Concentration gradient
Question 4
Transport of materials across the plasma membrane that does not require energy from the cell but does use transport proteins is called __________.
Channel proteins
A. osmosis
B. simple diffusion
Concentration gradient
Plasma membrane
Section 1 Check

45. Concentration gradient
Question 4
Transport of materials across the plasma membrane that does not require energy from the cell but does use transport proteins is called __________.
Channel proteins
C. facilitated diffusion
Concentration gradient
Plasma membrane
D. active transport
Section 1 Check

46. Concentration gradient
The answer is C. Facilitated diffusion is a type of passive transport and requires no energy from the cell.
Channel proteins
Concentration gradient
Plasma membrane
Section 1 Check

47. End of Chapter 8 Show