Practice question · Multiple choice
Why do phospholipids form a bilayer spontaneously when placed in water?
Hints
- Consider what each end of the molecule does in contact with water.
- A hydrophilic head and hydrophobic tails cannot both be satisfied unless the tails hide from water.
Show the answer
C. They are amphipathic, so water excludes the tails while accepting the heads
Why
A phospholipid has a water-loving head and water-fearing tails, so the only arrangement satisfying both is a sheet with tails buried inside. Water does the organising by exclusion, no machinery is needed, which is why membranes could arise before any protein existed to build them.
Practise What Is Life? The Chemistry of Living Things
The app has 4 more questions on this lesson, and keeps your place in the course. Biology I is free to start.
More questions on What Is Life? The Chemistry of Living Things
- A protein chain is assembled from 150 amino acids joined into one continuous strand. How many water molecules…
- Match each level of protein structure to what holds it together.
- Sort each statement by whether it describes condensation or hydrolysis.
- Arrange these levels of biological organisation from smallest to largest.
- Denaturation destroys a protein's biological function while leaving its primary covalent backbone intact.…
- Which statements about enzymes are correct?