1. CELL TRANSPORT
Objectives
Identify the main functions of the cell membrane
Describe what happens during diffusion
Explain the processes of osmosis, facilitated diffusion, and active transport.

2. Membrane Structure
1. Cell membranes are composed of a double- layered sheet called a phospholipid bilayer.

4. 2. Membrane Proteins
Proteins run through the lipid bilayer and form channels and pumps to move material across the cell membrane.

5. 3. Carbohydrate Molecules
They form chains that are attached to the outer surfaces of these proteins.
Many carbohydrates act like chemical identification cards, allowing cells to identify one another.

6. What does a Cell Membrane DO?
The cell membrane regulates what enters and leaves the cell and also provides protection and support.
The cell takes in food, water and ions and eliminates wastes through its membrane.
Some molecules, like water moves freely through the membrane, other molecules must be carried/pumped through channels.

7. (High concentration to Low concentration)
Passive Transport – does NOT use energy to move substances across a cell membrane.
the movement of molecules and ions with the concentration gradient.
(High concentration to Low concentration)

8. How do things get in and out of cells?
Diffusion is the process by which substances spread through a liquid or gas.
Substances move from regions of high concentration to regions of low concentration
NO energy required

9. Substances such as non-charged molecules, alcohol, water, and small lipids easily diffuse across the lipid bilayer.

10. Concentration Gradient
A difference in number of molecules (or ions) of a substance between two adjacent regions.

11. Equilibrium
After the substances move from high to low concentration,then the concentration of the substance on both sides of the membrane will be the same (equal).
Even after equilibrium is reached, individual molecules continue to move rapidly across the membrane in both directions.

12. How do things get in and out of cells?
Osmosis – the diffusion of water through a selectively permeable membrane. (molecules move from high to low concentrations)
Since water molecules are small, they can slip through the gaps between phospholipids in the cell membrane.
As a result, water molecules constantly move back and forth through the cell membrane.

13. How do things get in and out of cells?
Permeable- if a substance is able to diffuse across a membrane
Impermeable- if things cannot pass across the membrane
Selectively Permeable –some substances can pass across, others cannot.

14. Example-Osmosis
Example shows a membrane that is permeable to water but is not permeable to sugar.
On one side of membrane is a sugar solution, other side is pure water.
As a result, there is a net movement of water into the sugar solution. This is due to diffusion (movement from high concentration to regions of low concentration).

15. How do things get in and out of cells?
Facilitated Diffusion- uses carrier proteins to shuttle molecules across the lipid bilayer. (high to low conc.)
This movement of a substance across a membrane occurs without the input of the cell’s energy.
 ex: transports large glucose molecules from the blood into body cells.

16. PASSIVE TRANSPORT

17. Why do water molecules move with osmosis?
Osmoregulation- the control of water movement across the cell membrane.
Water “follows” solute.
Solute- a substance dissolved in solvent
Tonic- term used to refer to solvent
Hypertonic- more solute in solvent outside of cell
Hypotonic- less solute in solvent outside of the cell
Isotonic- equal amount of solute outside of cell and inside of cell.
Solute is usually charged and does not move through membrane

18. Why do water molecules move with osmosis?
Hypertonic solution
Solute concentration outside the cell is HIGHER than solute concentration inside the cell.
Water is moving OUTSIDE the cell to follow solute
Cell shrinks
plasmolysis

19. Why do water molecules move with osmosis?
Hypotonic solution
Solute concentration outside the cell is LOWER than solute concentration inside the cell.
Water is moving INSIDE the cell to follow solute
Animal cell swells and will possibly burst
Cytolysis
Plant cell swells until cell walls restrict further swelling
Turgor pressure

20. Why do water molecules move with osmosis?
Isotonic solution
Solute concentration is the same inside and outside the cell.
Water moves equally into and out of the cell.
Normal Cell

21. (Low to High concentration)
3. Active Transport – uses energy to move substances across a cell membrane.
the movement of molecules and ions against the concentration gradient.
(Low to High concentration)
Active Transport:

22. ACTIVE TRANSPORT

23. Example of Active Transport
Plant nutrients (solutes) are more concentrated inside the roots than in the surrounding soil. (this is good!)
Without active transport, these nutrients would diffuse out of the roots.

24. Examples of Active Transport
Sodium-potassium pump- concentration gradients of sodium and potassium allow for cellular communication.

25. Bulk Movement (huge molecules)
Transporting very large molecules such as polysaccharides or large proteins across the membrane.
Materials all move across the cell membrane packaged in membrane-bound sacs called vesicles. The vesicle merges with the cell membrane.

26. Endocytosis During endocytosis materials are brought INTO the cell.
a portion of the cell membrane surrounds desirable macromolecules that are outside the cell. The cell pinches off and the new vesicle moves into the cell.
Example: when white blood cells engulf foreign particles like bacteria and viruses.

27. Types of Endocytosis Pinocytosis- fluid transported into cell
Phagocytosis- food particles transported into cell

28. Exocytosis During exocytosis materials EXIT the cell
wastes and cell products are packaged by the Golgi Apparatus in sacs called vesicles. They then fuse with the cell membrane and the materials in the vesicles are secreted out of cell.
Ex: tear production
In Da Club- best review video 

29. Cellular Transport Membrane Structure consists of
1. Cell membranes are composed of a double- layered sheet called a ___
__________________________

30. 2. Membrane Proteins
Proteins run through the lipid bilayer and form ___________ and ___________ to move material across the cell membrane.

31. 3. Carbohydrate Molecules
They form chains that are attached to the outer surfaces of these proteins.
Many carbohydrates act like chemical ___________ cards, allowing cells to identify one another.

32. What does a Cell Membrane DO?
The cell membrane ___________ what enters and leaves the cell and also provides ___________ and ___________ .
The cell takes in food, water and ions and eliminates ___________ through its membrane.
Some molecules, like water moves freely through the membrane, other molecules must be carried/pumped through channels.

33. (High concentration to Low concentration)
Passive Transport – does ______ use energy to move substances across a cell membrane.
the movement of molecules and ions with the concentration gradient.
(High concentration to Low concentration)

34. How do things get in and out of cells?
Diffusion is the process by which substances __________ through a liquid or gas.
Substances move from regions of high concentration to regions of low concentration
NO energy required

35. Substances such as non-charged molecules, alcohol, water, and small lipids easily ___________ across the lipid
bilayer.

36. Concentration Gradient
A ___________ in number of molecules (or ions) of a substance between two adjacent regions.

37. Equilibrium
After the substances move from high to low concentration,then the concentration of the substance on both sides of the membrane will be the same (___________ ).
Even after equilibrium is reached, individual molecules continue to move rapidly across the membrane in ___________ directions.

38. How do things get in and out of cells?
Osmosis – the ___________ of water through a selectively permeable membrane. (molecules move from high to low concentrations)
Since ___________ molecules are ___________ , they can slip through the gaps between phospholipids in the cell membrane.
As a result, water molecules constantly move back and forth through the cell membrane.

39. How do things get in and out of cells?
Permeable- if a substance is able to diffuse across a membrane
Impermeable- if things ___________ pass across the membrane
Selectively Permeable –some ___________ can pass across, others cannot.

40. Example-Osmosis
Example shows a membrane that is permeable to water but is not permeable to ___________ .
On one side of membrane is a sugar solution, other side is pure water.
As a result, there is a ______ movement of water into the sugar solution. This is due to diffusion (movement from high concentration to regions of low concentration).

41. How do things get in and out of cells?
Facilitated Diffusion- uses carrier ___________ to shuttle molecules across the lipid bilayer. (high to low conc.)
This movement of a substance across a membrane occurs without the input of the cell’s energy.
 ex: transports large ___________ molecules from the blood into body cells.

42. Why do water molecules move with osmosis?
Osmoregulation- the ___________ of water movement across the cell membrane.
Water “___________ ” solute.
Solute- a substance dissolved in solvent
Tonic- term used to refer to solvent
Hypertonic- __________ solute in solvent outside of cell
Hypotonic- _______ solute in solvent outside of the cell
Isotonic- ___________ amount of solute outside of cell and inside of cell.
Solute is usually charged and therefore does not move through membrane

43. Why do water molecules move with osmosis?
Hypertonic solution
Solute concentration outside the cell is ___________ than solute concentration inside the cell.
Water is moving OUTSIDE the cell to follow solute
Cell ___________
plasmolysis

44. Why do water molecules move with osmosis?
Hypotonic solution
Solute concentration outside the cell is ___________ than solute concentration inside the cell.
Water is moving INSIDE the cell to follow solute
Animal cell ___________ and will possibly burst
Cytolysis
Plant cell swells until cell walls restrict further swelling
Turgor pressure

45. Why do water molecules move with osmosis?
Isotonic solution
Solute concentration is the ___________ inside and outside the cell.
Water moves equally into and out of the cell.
Normal Cell

46. (Low to High concentration)
3. Active Transport – uses ___________ to move substances across a cell membrane.
the movement of molecules and ions against the concentration gradient.
(Low to High concentration)

47. Example of Active Transport
Plant nutrients (solutes) are more concentrated inside the roots than in the surrounding soil. (this is good!)
Without active transport, these nutrients would diffuse out of the roots.

48. Examples of Active Transport
Sodium-potassium pump- concentration gradients of sodium and potassium allow for cellular communication.

49. Bulk Movement (huge molecules)
Transporting very ___________ molecules such as polysaccharides or large proteins across the membrane.
Materials all move across the cell membrane packaged in membrane-bound sacs called ___________ . The vesicle merges with the cell membrane.

50. Endocytosis
During endocytosis materials are brought ___________ the cell.
a portion of the cell membrane surrounds desirable macromolecules that are outside the cell. The cell pinches off and the new vesicle moves into the cell.
Example: when white blood cells ___________ foreign particles like bacteria and viruses.

51. Types of Endocytosis Pinocytosis- ___________ transported into cell
Phagocytosis- ___________ particles transported into cell

52. Exocytosis During exocytosis materials ___________ the cell
wastes and cell products are packaged by the Golgi Apparatus in sacs called vesicles. They then fuse with the cell membrane and the materials in the vesicles are secreted out of cell.
Ex: tear production