A LITTLE LIGHTBULB MOMENT
Cell biology and membranes
Amphipathic phospholipids
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Soap-dish molecules love both water and oil
The idea behind the cue
Phospholipids are amphipathic: hydrophilic heads interact with water, while hydrophobic tails avoid it. In water they spontaneously form bilayers, micelles, or vesicles depending on geometry. This self-assembly underlies membrane formation.
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Short & simple
Soap-dish molecules love both water and oil
Acronym
HHB — Hungry Hippos Bounce.
Story
A soap bubble party fills a sink. Each guest has a watery face and greasy shoes, so they line up with faces out and shoes tucked in. The result is a neat double row.
Connect the pieces
- H (Hungry) → Hydrophilic: The head groups like water and face the watery surroundings.
- H (Hippos) → Hydrophobic: The tails avoid water and hide away from it.
- B (Bounce) → Bilayer: In water, phospholipids self-assemble into bilayers, micelles, or vesicles depending on shape.
- Hungry · Hydrophilic: The head groups like water and face the watery surroundings.
- Hippos · Hydrophobic: The tails avoid water and hide away from it.
- Bounce · Bilayer: In water, phospholipids self-assemble into bilayers, micelles, or vesicles depending on shape.
Know the limits
Best applies in aqueous environments; membrane behavior also depends on cholesterol and temperature.
Further reading · OpenStax science textbooks ↗Check your understanding
Why do phospholipids form bilayers in water?
A. Their tails are attracted to water
B. Their heads are hydrophilic and tails are hydrophobic
C. They are held together by covalent bonds to water
D. They require membrane proteins to arrange themselves
Reveal explanation
Their heads are hydrophilic and tails are hydrophobic
Amphipathic phospholipids self-assemble because hydrophilic heads interact with water and hydrophobic tails avoid it.