Join thousands of students who trust us to help them ace their exams!Watch the first video
Multiple Choice
Why do phospholipids form bilayers when mixed with water?
A
Because they are completely hydrophilic and dissolve in water.
B
Because they are completely hydrophobic and repel water.
C
Because their hydrophilic tails repel water and their hydrophobic heads attract water.
D
Because their hydrophobic tails repel water and their hydrophilic heads attract water.
Verified step by step guidance
1
Phospholipids are amphipathic molecules, meaning they have both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts.
The structure of a phospholipid includes a hydrophilic 'head' containing a phosphate group and two hydrophobic 'tails' made of fatty acid chains.
When phospholipids are mixed with water, the hydrophilic heads are attracted to the water molecules, while the hydrophobic tails avoid water.
To minimize the exposure of the hydrophobic tails to water, phospholipids arrange themselves into a bilayer, with the hydrophobic tails facing inward, shielded from water, and the hydrophilic heads facing outward, interacting with the water.
This bilayer formation is energetically favorable and forms the basic structure of cell membranes, providing a stable barrier between the cell's interior and its external environment.