1. Movement in and out of a cell
Plasma Membrane
Movement in and out of a cell

2. Plasma Membrane
A flexible boundary between the cell and it’s environment
JOB: allow steady supply of nutrients to come into the cell no matter what the external conditions are
Too much of any nutrient or other substance can be harmful

3. Plasma Membrane (PM)
Process of maintaining balance in a cell’s environment is homeostasis
Selective permeability allows some molecules to pass through while keeping other out
Ex: screen on a window

4. PM: Structure
Lipids are large biomolecules composed of glycerol and 3 fatty acids
If a phosphate replaces one of the fatty acids, a phospholipid is formed
PM is made up of a phospholipid bilayer (2 layers of phospholipids back-to-back

5. PM: Structure
2 fatty acid chains are non-polar and form the tail of the phospholipid
The head contains the phosphate group and is polar

6. Continued Water is a key component of life
Polar head allows PM to interact with watery environment (H2O is a polar molecule) (Hydrophyllic) water loving
Non-polar tails avoid water (Hydrophobic) water fearing
Phospholipid molecules make a sandwich with tails in, heads out.

7. PM: Fluid Mosaic Model PM is not static (it doesn’t stay still)
Phospholipids move within the membrane like water molecules move with currents in a lake
Proteins also move through phospholipids like boats
Proteins create “mosaic” or pattern on membrane surface

8. PM: Other Components
Cholesterol: helps stabilize phospholipids by preventing tails from sticking together
Transport proteins: Span entire membrane
Regulate which molecules enter and leave cell
Proteins on OUTER surface help cells identify chemical signals and each other
Proteins on INNER surface help attach PM to cells internal support structure  flexibility

9. PM: Other Components

10. Show me What You Know
The structure most responsible for maintaining cell homeostasis is the ___.
Cytoplasm
Mitochondrion
Cell Wall
Plasma Membrane

11. Show me What You Know
The structure most responsible for maintaining cell homeostasis is the ___.
Cytoplasm
Mitochondrion
Cell Wall
Plasma Membrane

12. Show Me What You Know
Movement of particles from an area of higher concentration to one of lower concentration is ______________?

13. Show Me What You Know
Movement of particles from an area of higher concentration to one of lower concentration is ______________?
Diffusion

14. Show Me What You Know
Which of the following structures is the most complex?
Cell
Organ System
Organ
Tissue

15. Show Me What You Know
Which of the following structures is the most complex?
Cell
Organ System
Organ
Tissue

16. Activity Write your summary of notes
On the left hand side of your notebook, draw and label a phospholipid bilayer. Use p of your text. Don’t forget to add color.

17. Plasma Membrane
Day Two

18. Cell Transport 2 types of cell transport:
Passive Transport: Movement of particles across a membrane requiring NO energy
High concentration  Low concentration
Active Transport:

19. Passive Transport: Osmosis
Osmosis: diffusion of H2O across a selectively permeable membrane.
Ex. If membrane that only allows water to pass through, water will diffuse to side where H2O concentration is lower and will continue until equal concentration is reached on both sides

20. Passive Transport: Osmosis
Isotonic Solution: Concentration is the same both inside and outside the cell
Hypotonic Solution: concentration is lower outside than inside the cell
Hypertonic Solution: concentration is higher outside than inside the cell

21. Passive Transport: Osmosis

22. Passive Transport: Diffusion
Diffusion: net movement of particles from higher concentration to lower.
Results from random movement of particles running into one another
Very slow process because it relies on random motion

23. Continued 3 key factors:
Concentration: Increase in concentration will increase the rate of diffusion
Temperature: Increase in temperature will increase rate of diffusion
Pressure: Increase in pressure will increase rate of diffusion
Dynamic Equilibrium: continuous movement with no overall concentration change

24. Passive Transport: Diffusion

25. Active Transport
Active Transport: Movement of materials through a membrane against a concentration gradient (requires energy)

26. Active Transport: Carrier Transport Proteins
Carrier Proteins:
Bind with particle of the substance to be transported
Lock and Key!!
With the right fit, chemical energy allows shape of carrier protein to change releasing particle on other side
Much like the action of a door

27. Active Transport: Carrier Proteins

28. Active Transport: Endocytosis
Endocytosis occurs when the cell surrounds and takes in large material from it’s environment
Does not pass through membrane
Engulfed and enclosed by part of the PM
Membrane breaks away creating a vacuole with the material inside
Phagocytosis: cell brings in a solid
Pinocytosis: cell brings in liquid

29. Active Transport: Exocytosis
Exocytosis occurs when the cell expels or secretes large particles from the cell
Ex. wastes, hormones

30. Show Me What You Know
Water moves into a cell placed in a(n) __________ solution.
Osmotic
Hypertonic
Hypotonic
Isotonic

31. Show Me What You Know
Water moves into a cell placed in a(n) __________ solution.
Osmotic
Hypertonic
Hypotonic
Isotonic

32. Show Me What You Know
Water moves out of a cell if the cell is placed in a(n) ___________ solution.
Hypertonic
Isotonic
Hyptonic
passive

33. Show Me What You Know
Water moves out of a cell if the cell is placed in a(n) ___________ solution.
Hypertonic
Isotonic
Hyptonic
passive

34. Show Me What You Know
A cell moves particles from a region of lesser concentration to a region of greater concentration by ____________.
Facilitated diffusion
Passive transport
Osmosis
Active Transport

35. Show Me What You Know
A cell moves particles from a region of lesser concentration to a region of greater concentration by ____________.
Facilitated diffusion
Passive transport
Osmosis
Active Transport

36. Activity Write a summary for your notes
Create a foldable to be glued into the activity page of your notebook. Use p. 195 of your text to create the foldable. Don’t forget to use at least 4 colors