1. Cell Transport
Chapter 7.3

2. Importance of regulating transport in and out

3. Cell Membrane
______________________of molecules in and out to keep the inside of the cell relatively constant (What’s that called?)

4. Cell Membrane
Regulates movement of molecules in and out to keep the inside of the cell relatively constant (What’s that called?)

5. Passive Transport
Diffusion – particles moving from an area of high concentration to low concentration
Takes place by __________ _______and spreading out of molecules in gas or liquid
Eg dye diffusing through a bowl of water (without being stirred)

6. Passive Transport
Diffusion – particles moving from an area of high concentration to low concentration
Takes place by random collisions and spreading out of molecules in gas or liquid
Eg dye diffusing through a bowl of water (without being stirred)

7. Down the concentration gradient

8. Diffusion across a permeable membrane
Permeable to a substance = _____________ _____________________________________
Eg – moving through a bowl of water with a sieve in it – the dye moves in and out of the sieve freely

9. Diffusion across a permeable membrane
Permeable to a substance = that substance can move across it freely
Eg – moving through a bowl of water with a sieve in it – the dye moves in and out of the sieve freely

10. Equilibrium
Equilibrium = __________________________ _____________________________________
There is still movement of the molecules in both directions across the membrane, but in equal numbers

11. Equilibrium
Equilibrium = when there is an equal concentration on both sides of the membrane
There is still movement of the molecules in both directions across the membrane, but in equal numbers

12. True or false: When equilibrium is reached, the molecules stop moving across the membrane

13. Facilitated Diffusion
Movement of molecules across the membrane ______________than would have been expected
Molecules that are large or have a + or – charge or are polar – should not pass through the lipid easily
Happens because proteins imbedded in the membrane act as channels or carriers
Each protein is specific for one kind of molecule to pass through
The movement is still down the concentration gradient, and still does not require energy, so is still a form of passive transport

14. Facilitated Diffusion
Movement of molecules across the membrane much faster than would have been expected
Molecules that are large or have a + or – charge or are polar – should not pass through the lipid easily
Happens because proteins imbedded in the membrane act as channels or carriers
Each protein is specific for one kind of molecule to pass through
The movement is still down the concentration gradient, and still does not require energy, so is still a form of passive transport

16. Semi-permeable membrane
Selectively permeable membrane
Lets through some things but not other things
Due to
Size
Charge

17. Osmosis Facilitated Diffusion of Water
Osmosis is diffusion of water through a selectively permeable membrane
Still moving from an area of higher to lower concentration, but looking at concentration of water rather than the solute

18. What is osmosis?

19. Osmosis moves water to where there is more solute
Equilibrium will be reached when there is an equal concentration of solute on both sides of the membrane (even if the water has to push against the pressure of gravity)

20. Concentrations Isotonic – _________ strength (on both sides)
Hypertonic – ________ strength
Hypotonic – __________ strength
Tonicity always refers to __________________

21. Concentrations Isotonic – same strength (on both sides)
Hypertonic – higher strength
Hypotonic – lower strength
Tonicity always refers to the solution rather than the cell

22. Hypertonic Hypotonic Isotonic

23. Effect of Osmosis on Cells

24. Osmotic Pressure
Movement of water into or out of cells produces osmotic pressure
A cell in hypertonic fluid will _______ from water being forced out
A cell in hypotonic fluid will ________ from water being forced in
Plant cells have rigid walls that do not let them shrink or swell

25. Osmotic Pressure
Movement of water into or out of cells produces osmotic pressure
A cell in hypertonic fluid will shrink from water being forced out
A cell in hypotonic fluid will swell from water being forced in
Plant cells have rigid walls that do not let them shrink or swell

26. Active Transport
Movement of molecules up (against) the concentration gradient
From ____________________concentrated area
Requires ________________ from the cell

27. Active Transport
Movement of molecules up (against) the concentration gradient
From less to more concentrated area
Requires energy from the cell

28. Molecular Transport
Accomplished by protein pumps – proteins _____ __________that change shape to carry the molecule across

29. Active Transport
Accomplished by protein pumps – proteins in the membrane that change shape to carry the molecule across

30. Which is passive and which is active transport?
What are the two differences?
Left passive, right active
With or against concentration gradient; use of ATP (cellular energy)

31. Is diffusion active or passive transport?

32. If a cell is in an isotonic solution, what happens to it?
Draw a diagram

33. If a cell is in an hypertonic solution, what happens to it?
Draw a diagram

34. If a cell is in an hypotonic solution, what happens to it?
Draw a diagram