Transport across membranes

Question 1

How can molecules more across membranes?

Answer 1

• Diffusion/Facilitate Diffusion
• Osmosis
• Active transport
• Bulk Transport

Question 2

What is selective permeability?

Answer 2

• It is when certain molecules can move across relatively easily whilst others may need a little help or not be able to cross it at all.
• By providing a carrier or channel proteins for wanted molecules/ions only.

Question 3

What methods determine whether a molecules can cross a membrane?

Answer 3

• It size
• Whether it is charged or polar
• Whether it needs to move down or against a concentration gradient