Cell Transport Study Guide

1. Which forms of transport do NOT require energy?

• Diffusion• Osmosis• Facilitated Diffusion

*All of these are passive!

2. Which forms do require energy?

• Endocytosis• Exocytosis• Sodium-Potassium Pump

*All of these are active!

3. At the end of the diffusion process, the concentration of substances on

each side is _____________.

• Equal

4. Draw an illustration of diffusion.

• On right side of board.

• Sugar molecules start out lumped together and gradually move until they are evenly spread out.

5. Define diffusion.

• Movement of molecules from an area of high concentration to an area of low concentration.

6. Red blood cells have a salt concentration of 0.9%

• In a solution of 1.2% salt, they will shrink because water moves out of the cell.

• In a 0.9% saline solution, they will remain the same because the two are equal.

• In pure water, they will swell because water will move into the cell.

7. Define osmosis.

• Diffusion of water molecules.

8. In the diagram, which direction will the substances move?

• From left to right (high conc. to low conc.)

10. A cell will swell when it is placed in a __________ solution.

• hypotonic

11. A cell will shrink when placed in a _____________ solution.

• hypertonic

12. A cell will remain the same when placed in an ___________ solution.

• isotonic

13. What is the difference between active and passive transport?

• Active requires energy and moves molecules against their concentration gradient.

• Passive does not require energy and moves molecules down their concentration gradient.

14. Proteins that act like selective passageways in the cell membrane

are known as ___________.

• Channel proteins

15. What kind of molecules can pass through the cell membrane unaided?

• Small, nonpolar

16. During the egg demo, the egg gains mass and became swollen. What is the

explanation for this?

• It was placed in a hypotonic solution and water moved into the egg.

17. What is the energy source for active transport?

• ATP

18. Molecules that are too large to be moved through the membrane can be transported into the cell by _______.

• Endocytosis

19. Ridding the cell of materials by discharging the materials in vesicles is

called ______________.

Exocytosis

20. Describe the Sodium-Potassium pump. What type of transport is it?

• A protein in the cell membrane that moves Na and K ions against their concentration gradient. It requires ATP, so it is active transport.

21. Describe the lipid bilayer.

• Drawing on board!• It is a double layer of phospholipids arranged

tail to tail, making up the cell membrane.

22. Define concentration gradient.

• A difference in concentrations.

23. What is equilibrium?

• Balance

A cell membrane is ______ permeable because it allows for the passage of some substances but not others.

• Semi or selectively