1. Passive Transport Guiding Questions Answers
What size molecules can pass through a membrane by a process called passive transport?
What is a semipermeable membrane?
What is the advantage of passive transport?
Why is facilitated diffusion
a type of passive
transport?
Small molecules pass through a membrane by a process called passive transport
A membrane that allows only certain substances into or out of a cell
The cell does not have to use energy to get materials it needs.
Facilitated diffusion moves
substances through a cell’s
membrane without using
energy.

2. Diffusion Guiding Questions Answers
What caused the concentration of dye to change in the beakers?
What do you think would happen if dye had been added to both sides of the membrane?
The dye moved through the membrane from the higher concentration side to the lower concentration side.
The water and dye would move in both directions through the membrane until there were equal concentrations on both sides.

3. Osmosis The diffusion of water across a cellular membrane.
Cell membranes allow water to pass through them until equilibrium is reached.
3. In plants, water stored in the
central vacuole will allow
water to diffuse out if the
concentration of water in the
air is higher than that it in the
plant. This is why eventually
because they lose water.
What is Osmosis?
2. How does osmosis work?
3. What is an example of osmosis?

4. Active Transport Guiding Questions Answers
Active transport uses the cell’s energy.
2. 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. 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.
Which type of movement through a cell membrane requires the cell to use energy?
How does the movement of molecules from one concentration to another different between active transport and passive transport?
When does a cell need to use active transport?