Which molecules are the main constituents of cell membranes?

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Multiple Choice

Which molecules are the main constituents of cell membranes?

Phospholipids form the main structure of cell membranes because they are amphipathic molecules that spontaneously assemble into a bilayer in water. The hydrophilic heads face the aqueous environments on the inside and outside of the cell, while the hydrophobic tails hide away in the interior. This arrangement creates a stable, semi‑permeable barrier that defines the membrane’s basic structure. Other components like proteins, cholesterol, and carbohydrate groups are important for function and regulation, but they do not make up the majority of the membrane’s material. Carbohydrates are mainly on the outer surface, attached to lipids or proteins, and nucleic acids reside inside the cell or nucleus rather than in the membrane.

Phospholipids form the main structure of cell membranes because they are amphipathic molecules that spontaneously assemble into a bilayer in water. The hydrophilic heads face the aqueous environments on the inside and outside of the cell, while the hydrophobic tails hide away in the interior. This arrangement creates a stable, semi‑permeable barrier that defines the membrane’s basic structure. Other components like proteins, cholesterol, and carbohydrate groups are important for function and regulation, but they do not make up the majority of the membrane’s material. Carbohydrates are mainly on the outer surface, attached to lipids or proteins, and nucleic acids reside inside the cell or nucleus rather than in the membrane.

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