11. Permeability theory

What does the membrane do?

Act as a barrier

How permeable is the cell membrane?

Cell membrane is selectively permeable to water and some solutes

What can go through the cell membrane more easily than others?

Lipid soluble (non polar) can move through more easily than water soluble (polar)

How do small uncharged non polar molecules pass?

Freely pass through membrane by simple diffusion

What can pass through the cell membrane by simple diffusion?

Small uncharged non polar molecules (e.g. oxygen and carbon dioxide)

What kind of soluble molecules can pass through the cell membrane? Example?

Lipid soluble molecules like glycerol can pass through

What does the hydrophobic core of membranes stop being transported?

Ions and polar molecules

What stop ions and polar molecules not passing through?

Hydrophobic core of membranes

What cannot diffuse across the non polar centre of phospholipid bilayer?

Charged particles (ions) and large charged molecules (glucose) -> insoluble in lipid

What can charged particles (ions) and large charged molecules (glucose) not do?

Cannot diffuse across non polar centre of phospholipid bilayer

What allow charged particles (ions) and large charged molecules (glucose) to pass?

Intrinsic proteins -> channels and carriers allow facilitated diffusion

What do pumps do?

Carry out active transport