Facilitated Diffusion

Question 1

What are protein channels?

Answer 1

Ions / water soluble molecules move across membranes down a concentration gradient. They pass through water filled channel proteins, each only transport one type of ion. The channel will open in the presence of the ion but will otherwise be closed.

Question 2

What are protein carriers?

Answer 2

Glucose binds to a specific carrier, the carrier changes its shape. They glucose is transferred to the other side of the membrane. They physically change shape.

Question 3

Facilitated diffusion =

Answer 3

High to low

Question 4

What is facilitated diffusion?

Answer 4

Channel and carrier proteins allow movement of polar/charged substances across a plasma membrane by passive transport as they can’t interact with non polar fatty acid chains. Some substances e.g. ions, glucose, amino acids can’t pass through. They are helped by proteins which act as channels or carriers.

Question 5

Does it require energy?

Answer 5

I’d doesn’t require ATP, it has kinetic energy down the concentration gradient.

Question 6

Summary of facilitated diffusion?

Answer 6

An example of a molecule transported by it is large polar molecules such as glucose. It occurs down a concentration gradient and it both directions and it requires proteins but not ATP.