1. Cell Membranes & transport of molecules through it
KL biology

2. Functions of cell Membranes
1. Protect cell 2. Control incoming and outgoing substances 3. Maintain ion concentrations of various substances (Calcium, Sodium, etc.) 4. Selectively permeable- allows some molecules in, others are kept out

3. Prefixes/Suffixes Phospholipid bilayer Hydro- water
Hydrophobic tail (lipid)
Hydrophilic head (phosphate)
Prefixes/Suffixes
Hydro- water
Philic- being attracted
Phobic- fear of

4. Functions of the membrane

5. Solutions Solute- substance that’s dissolved (ex. salt or sugar)
Solutions are made of a solute and a solvent
Solute- substance that’s dissolved (ex. salt or sugar)
Solvent- liquid the solute is dissolved in (ex. water)

6. Solutions

7. Vocabulary
Hypertonic Solution- higher concentration of solute (more molecules)
Isotonic Solution- solutions have same concentration of solute
Hypotonic Solution- lower concentration of solute (less molecules)

8. Isotonic Solution
Isotonic=Same amount of solute inside the cell as is in the solution its in
having equal osmotic pressure as the comparison solution.
Same amount of water flows into as flows out of the cell

9. Hypotonic Solution
Hypotonic= greater concentration of solute inside the cell, than outside the cell
Cell has a higher osmotic pressure (internally) than a comparison solution
turgor pressure- force exerted on the membrane/wall
High turgor pressure can cause cytolysis-which is the bursting of cell membranes

10. Hypertonic Solution
Hypertonic= a greater concentration of solute outside the cell, than inside the cell.
Cell has a lower osmotic pressure (internally) than a comparison solution
Low turgor pressure causes plasmolysis, which is “cell shrinking”.
causes plants to wilt

11. Membrane Transport (Getting molecules Across a cell membrane)
1. Diffusion 2. Osmosis 3. Facilitated Diffusion 4. Active Transport

12. Diffusion
Movement of any type of molecule from high to low concentration
Passive Transport- No energy needed
So diffusion is a from of passive transport

13. Diffusion

14. Membrane Transport (Getting molecules Across a cell membrane)
1. Diffusion 2. Osmosis 3. Facilitated Diffusion 4. Active Transport

15. Osmosis- water moving through a cell membrane

16. Membrane Transport (Getting molecules Across a cell membrane)
1. Diffusion 2. Osmosis 3. Facilitated Diffusion 4. Active Transport

17. Facilitated Diffusion
Use proteins to carry molecules across the membrane
Like a piggy-back ride

18. Membrane Transport (Getting molecules Across a cell membrane)
1. Diffusion 2. Osmosis 3. Facilitated Diffusion 4. Active Transport

19. Active Transport
Requires energy(ATP) to transport molecules through the membrane
Moving molecules against a concentration gradient
Requires the use of “carrier Proteins”
Piggy-Back Ride + energy (ATP)

20. Types of transport

21. Osmosis- movement of water
Remember…
Osmosis- movement of water
Diffusion, Facilitated Diffusion and Active Transport- movement of molecules

22. Osmosis labs
Vegetable osmoregulation lab
Osmoregulation in elodea

23. Vegetable Osmoregulation Investigation
Title:
Vegetable Osmoregulation Investigation
Problem:
How are vegetable samples affected by hypertonic solutions? How are vegetable samples affected by hypotonic solutions?
Hypothesis (Prediction): If IV then DV because…
Experimental Design
Independent Variable (IV):
Levels of IV:
Dependent Variable (DV):
How will the DV be measured and/or observed?
Controlled Variables (2+):

24. Experimental Control Group:
How will you set up the beaker with only experimental controls? Which label will it have?
Experimental Group:
How will you set up the beaker that will answer the investigative question?