amphipathic molecule

[cellbiostudent]

What I know about amphipathic molecules are that they have both hydrophobic regions and hydrophilic regions. But why is it that in a aqueous solution the bilayer it is hydrophilic and monolayer is hrdrophobic?

[mith]

I'd assume you'd have to look at the structures formed in water.

[cellbiostudent]

the example that I am looking at the mono layer forms a sphere and the bilayer forms a vesicle that contains water.

[MrMistery]

because in a bilayer you have all the hydrophilic heads at the exterior and the hydrophobic tails together on the inside. In a monolayer, you have the hydrophilic heads on one side and the hydrophobic tails on the other, so one of the sides has to be hydrophobic.