Faciliated Diffusion and Co-transport

Question 1

Facilitated Diffusion

Answer 1

This is the diffusion of polar molecules through the carrier and channel proteins of the plasma membrane.

• Is passive - no ATP/energy is required
• Occurs down a concentration gradient

Question 2

Channel Proteins

Answer 2

Lined with polar groups (charged) so only hydrophilic substances across

Question 3

Carrier Proteins

Answer 3

Open and close by changing shape to allow larger polar molecules eg sugar and amino acids across

Question 4

Graph showing facilitated diffusion

Answer 4

The line will increase till it reaches a point where it will plateau. This is due to the amount of channels for diffusion to take place in being fixed

Question 5

Co-transport

Answer 5

Co-transport is a type of facilitated diffusion by which two substances are simultaneously transported across a membrane by a carrier protein
Occurs in ileum (small intestine) and kidney nephron