1. Bellringer-December 5, 2014 (Label the letters)
Extracellular Fluid
Cytoplasm

2. December 5, 2014 What types of molecules passes easily?
What types of molecules does not pass easily and needs assistance?

3. Answers a-glycoprotein B-glycolipid
C-Oligosaccharide chains (attached to glycoprotein)
D-nonpolar tails (fatty acid tails) (hydrophobic tails)
E-Phosopholipid bilayer
F-Polar heads (hydrophilic heads) (phosphate head)
G-Peripheral protein
H-cholesterol
I-Integral Protein
J-Cytoskeleton

4. Cell Movement: PassiveTransport
Honors Biology
Ms. Kim

5. Membrane structure LEADS TO selective permeability
A cell must exchange materials with its surroundings
a process controlled by the selectively permeable plasma membrane

6. Cell Transport Means moving things INTO and OUT of the cell
Cells need to take in
Food
Get rid of waste products (excretion)
Give out such useful substances as hormones and enzymes (secretion).

7. Permeability and Cell Transport
Hydrophobic (non polar) molecules
Are lipid soluble (can dissolve)
can pass through membrane easily
Ex: Hydrocarbons, CO2, O2
Hydrophilic (Polar) molecules
Are NOT lipid soluble (can’t dissolve)
Lipid INsoluble
Do not cross membrane easily
Ex: Na+, Cl- , Glucose/ other sugars
NOTE: CHARGED molecules need “help” to cross membrane
NOTE: LARGE molecules, POLAR molecules need “help”

9. Types of Cellular Transport
high
low
Weee!
Passive Transport
cells do NOT use energy
Diffusion
Facilitated Diffusion
Osmosis
Active Transport
cells DO use energy
Protein Pumps
Endocytosis
Exocytosis
high
low
This is going to be hard!

10. 1) Diffusion Diffusion:
Movement of molecules from a high concentration to a lower concentration
Does not use energy
Can occur in non-living systems (ex: dye)
Concentration:
Number of molecules of a substance in a given volume
Concentration gradient:
Difference in concentration of a substance from one location to another

11. Types of Passive Transport
Diffusion is the tendency for a population of molecules (of ANY substance) to spread out evenly into available space
A “net” movement
Ex: Perfume, a fart , tea, food coloring in water (see demo)

12. DIFFUSION In absence of other forces…
Molecules move (diffuse) from area of HIGH [ ] to an area of lower [ ]
A.k.a. Molecules move DOWN its OWN concentration gradient
No chemical work (ATP energy) is used diffusion is spontaneous!

14. Substances diffuse down their OWN concentration gradient
Figure 7.11 B
(b)
Net diffusion
Equilibrium

15. copyright cmassengale
The Plasma Membrane
4/20/2017
Diffusion of Liquids
copyright cmassengale
G. Podgorski, Biol. 1010

16. Factors Affecting Diffusion
1. Temperature
Higher temperature  more kinetic energy  molecules move faster
2. Pressure
Higher pressure  molecules move faster
ExampleTea: Higher temperature and more pressure (twirling/stirring) it around) makes diffusion happen faster.

17. 2) Facilitated Diffusion
Molecules move down (not against) a concentration gradient with the aid of special proteins (channel or carrier proteins)
Speeds up the process
Proteins CAN change SHAPE
Does NOT use energy (NO ATP NEEDED) = type of passive transport
Moves things from high to low concentrations
Moves POLAR molecules  can NOT easily pass through the membrane on it’s own.
Example: ions, smaller polar molecules (ex: sugar)

18. Channel proteins -Provide “tunnels”
Channel Proteins animations
Channel proteins -Provide “tunnels”
Figure 7.15
EXTRACELLULAR
FLUID
Channel protein
Solute
CYTOPLASM
A channel protein (purple) has a channel through which
water molecules or a specific solute can pass.
(a)

19. Carrier proteins -Undergo a subtle change in shape “carry” solute across the membrane

20. 3. Osmosis Osmosis: – diffusion of water across a membrane
Water moves across a semi-permeable membrane from an area of high water concentration to an area of low water concentration
If water can cross a membrane, but the solute cannot, then…
The water moves towards the side with MORE solute to balance the concentrations

21. Effects of Osmosis on Water Balance
The movement of water (water diffusion) across a semipermeable membrane
Involves the movement of FREE water molecules down a water [ ] gradient
High solute low “free” water [ ] or….
Low solute  high free water [ ]

22. Osmosis is affected by the concentration gradient of dissolved substances (solutes)
Osmosis animation

24. O S M I

25. Diffusion of H2O Across A Membrane
The Plasma Membrane
4/20/2017
Diffusion of H2O Across A Membrane
High H2O potential Low solute concentration
Low H2O potential High solute concentration
copyright cmassengale
G. Podgorski, Biol. 1010

26. Osmoregulation Osmoregulation – control of water balance
Turgor pressure – pressure inside a cell
Tonicity – tendency of a cell to lose or gain water based on the solution it is in
3 Types of solutions:
Isotonic
Hypotonic
Hypertonic

27. 3 Different Types of Solutions Recall: SOLUTION = a uniform mixture of 2 or more substances ** compare solutions OUTSIDE cell to inside cell
1. ISOTONIC-Solution has same concentration of dissolved particles as the cell (same amount of solute outside and inside the cell)
Water moves into and out of cell at equal rates and cell size remains constant
Cell does not change shape
There will be NO net movement of water

28. ISOTONIC SOLUTION
Result: Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium)

29. 2. If a solution is hypertonic
Solution has a higher concentration of dissolved particles than the cell (more solute outside of the cell than it is inside the cell)
Water flows OUT of the cell
The cell shrivels up and turgor pressure decreases
“hyper” means more
(high [solute])
Ex: when salinity increases in lake, fish can die!
NaCl
The water will move out of the fish towards the area with MORE solutes (ocean) to balance the concentrations! Poor fish…

30. HYPERTONIC SOLUTION
Result: Water moves from inside the cell into the solution: Cell shrinks (Plasmolysis)!

31. 3. If a solution is hypotonic
Solution has a lower concentration of dissolved particles than the cell (less solute outside of the cell than it is inside the cell)
Water flows INTO the cell
The cell swells/gets big!
Ex. Happens with distilled water
Animals:
Cytolysis (when a cell BURSTS!)
“hypo” means “less”
(low [solute])
Think: Hypo- sounds like hippo…hippos are big & round; cells in hypotonic solutions get big & round
Also, think “hypo” is “low” meaning “low” solutes SURROUNDING cell
“Hypo” is
LOW!!!

32. HYP0TONIC SOLUTION
Result: Water moves from the solution to inside the cell): Cell Swells and bursts open (cytolysis)!

33. Cell in ___________ Solution
The Plasma Membrane
4/20/2017
Cell in ___________ Solution
10% NaCL 90% H2O
ENVIRONMENT
CELL
NO NET MOVEMENT
10% NaCL
90% H2O
What is the direction of water movement?
Dynamic equilibrium
The cell is at ____________________.
G. Podgorski, Biol. 1010

34. Cell in ____________ Solution
The Plasma Membrane
4/20/2017
Cell in ____________ Solution
10% NaCL 90% H2O
ENVIRONMENT
CELL
20% NaCL
80% H2O
What is the direction of water movement?
copyright cmassengale
G. Podgorski, Biol. 1010

35. Cell in ___________ Solution
The Plasma Membrane
4/20/2017
Cell in ___________ Solution
15% NaCL 85% H2O
ENVIRONMENT
CELL
5% NaCL
95% H2O
What is the direction of water movement?
copyright cmassengale
G. Podgorski, Biol. 1010

36. Osmosis Animations for isotonic, hypertonic, and hypotonic solutions

40. Real life examples

41. Water Balance of Cells with Walls
Cell walls
Help maintain water balance
Cell walls are in:
Plants
Prokaryotes
Fungi
Some protists

42. Plant Cells & Solutions
Isotonic (Flaccid)
Plant cells at isotonic solutions are flaccid (can also be in hypertonic solution)
Cells are limp
Hypotonic (Turgid)
Plant cells prefer hypotonic solutions because the cell wall provides more support and plant cells are less likely to lyse (burst)
Turgor pressure increases (vacuole fills with water)
It is very firm
A healthy state in most plants
Plasmolysis Video -
Hypertonic (Plasmolysis)
Plants wilt, undergo plasmolysis
The cytoplasm and plasma membrane begin to pull away from the cell wall
Causes cell with walls to wilt & can be lethal.

43. Water balance in cells with walls
Plant cell. Plant cells are turgid (firm) and generally healthiest in a hypotonic environment, where the uptake of water is eventually balanced by the elastic wall pushing back on the cell.
(b)
H2O
Turgid (normal)
Flaccid
Plasmolyzed
Figure 7.13

44. Types of Cellular Transport#1
Passive Transport
DOES NOT require chemical energy (ATP) #2
Active Transport
DOES require chemical energy (ATP)

45. Exit Slip-December 5, 2014
Draw 3 cells in the following solutions AND draw water direction the water is moving (draw dots to represent the SOLUTE):
Hypertonic solution
Hypotonic solution
Isotonic solution