Membrane Transport

Membrane permability:

Passing through the lipid bilayer

• gases, non-polar covalent bonds cross most efficiently

• the larger in size, more polar covalent bonds, and charges there is the more harder it is to cross the membrane

  • these molecules would require a membrane protein to efficiently cross

How to determine what type of transport:

1. Consider the concentration gradient

   a. movement towards equilibrium concentration = passive transport

   • no energy input required

   b. mvoement away equilibrium concentration = active transport

   • requires energy source (ATP) and transport protein.

Passive Transport (favorable)

• passive transport occurs by diffusion

Active transport (unfavorable)

• ATP comes in and breaks down into ADP+P, which the phosphate attaches itself to the protein (changing it’s shape) opening/allowing the molecule to pass through