PowerPoint Notes

These notes should be copied into your spiral notebooks. Being absent means you copy them at home. This assignment may be used in a spiral notebook check. You are responsible for studying this information for you Chapter 2 Test (part two) for Dec. 15th.


1.What size molecules can pass through a membrane by a process called passive transport?

   Small molecules pass through a membrane by a process called passive transport

  2.What is a semipermeable membrane? 

 A  membrane that allows only certain substances into or out of a cell

3.What is the advantage of passive transport?

The cell does not have to use energy to  get materials it needs.
1.Which type of movement through a cell membrane requires the cell to use energy?
Active transport uses the cell’s energy.
2. How does the movement of molecules from one concentration to another differ between active transport and passive transport?
During active transport, a substance moves from an area of lower concentration to an area of higher concentration. This is the opposite of passive transport.
3. When does a cell need to use active transport?

Needs to use active transport to take in nutrients that have a lower concentration outside the cell or to get rid of wastes that have a lower concentration inside the cell.


1. What caused the concentration of dye to change in the beakers?

The dye moved through the membrane from the higher concentration side to the lower concentration side.

2. What do you think would happen if the dye had been added to both sides of the membrane?

The water and dye would move in both directions through the membrane until there were equal concentrations on both sides.